Hello everyone, this is DIY Renova.

Are there any people who want to try self-renovation, or who are thinking, "It's about time to understand the structure around the pillars of your home before you start working on it..."When you start thinking, "I'll reinforce and replace the pillars yourself!", you'll probably find yourself full of questions like, "What types of pillars are there in the first place?" and "Which loads support how much load?"

In this article, we will explain the pillars of Japanese wooden houses (estimating a maximum of two-story buildings) with a combination of "types of pillars," "their use," and "quantitative engineering perspective," so that even beginners can understand.Furthermore, we will also provide detailed instructions and points to note so that you can easily lead to actions like, "Okay, let's give it a try!" just by reading it as is.

This article contains over 6,000 characters, but please rest assured that it has been compiled as clearly as possible.If you read to the end, you can understand why pillars are important, where there are pillars, how they support them, what dimensions and materials are there, and how they are supported, and how to proceed with the work procedure.If you are interested in DIY renovations, please take a look.

Basic knowledge you should know before working with pillars in DIY renovations

1. If you want to move pillars (reinforcement and replacement), understand the "structure of the entire building."

Even if you think, "I'm worried about the pillars of the house, so I'll replace them for now!", the pillars are an important component that supports the entire house.In Japanese wooden houses (conventional construction methods), pillars, beams, girders, foundations, and braces are intricately combined to support the building.Even if you just replace one pillar, if you don't take into consideration the connection with the surrounding beams and walls, you may end up with excessive loads on other parts or, conversely, insufficient reinforcement.

• Simply put, DIYing involving pillars is the act of "partially remodeling the structure of a building."
• This is an incomparable risky task to a typical interior renovation (such as replacing cloths or replacing flooring).

Therefore, in this article, we will thoroughly explain the meaning of handling pillars, the minimum engineering knowledge, and the actual procedure.It is most important to take the initiative carefully, so be sure to take safety into consideration before proceeding.

2. Keep in mind that "twisting the structure = the possibility of violating the Building Standards Act"

Under Japanese law, a confirmation application may be required when renovating or expanding or renovating a building that involves altering the "structure" of a building.Be especially careful when removing walls or removing multiple pillars, which have a major impact on the stability of the structure.

• Even if you have a home up to two stories, in some cases you may have to consult with the government or a professional architect.
• Even if it is not a major renovation, remember that if you are repairing or renovating parts that affect the structure, you will need to apply for some confirmation.

The DIY work introduced in this article is essential to "must be responsible" and "if you don't know, consult a professional."Especially if you have any major issues, such as "wanting to pull out the through pillars," consult with an expert before taking action.

Understand the basic structure and role of pillars

1. The relationship between columns and beams

In wooden houses, horizontal materials such as beams and girders are combined with the pillars to support the floor, ceiling, and roof.It is an image of the columns being loaded in the vertical direction, and the beams and girders stitch them together horizontally.

• The pillars are the unsung forces that support the entire house "vertical".
• Beams and girders are yokozuna-like beings that support the "lateral direction."

Of course, the building is not made up of just pillars.The combination of braces and wall materials also resists horizontal forces such as earthquakes and wind.However, the most important point is "how solid the pillars are."

2. Imagine the load supported by a single pillar

In a two-story building, the pillars on the first floor support the load for two floors.What level of load is it?To give a rough idea, consider the following:

• "Load load" that weighs on furniture and people: Expected to be approximately 180-200 kg per square meter.
• "Fixed load" for floors, ceilings, finishing materials, etc.: Expected to be approximately 50-90 kg per square meter.

For example, if the floor area on the first floor is 40 square meters and the second floor is also 40 square meters, the total weight will be quite large.In addition to this, the weight of the roof and other parts is added, and horizontal force is applied during an earthquake or typhoon.It will probably convey "how important is one pillar."

Types of pillars: through pillars, pipe pillars, corner pillars, etc.

In traditional Japanese construction methods, there are two main pillar shapes: "through columns" and "tube columns", each of which has a different role.

1. Through pillar

This pillar "peels through the floor on the first floor to the roof (or shed beams) on the second floor."

• Features: The so-called "structural key" that is subject to the main load of the entire building.
• Use: Used in four corners of the house or in important positions.It also resists shaking during earthquakes and typhoons.

It is commonly called a "corner pillar," and when it is located near the middle, it is often called a "through pillar."This is an important pillar that literally runs up and down a two-storey building, so it is a huge risk to take it off or cut it by DIY.

2. Pipe column

The pillars are "installed on each floor" and, in the case of a two-storey building, separate pillars for the first floor and pillars for the second floor.

• Features: The load is slightly smaller than that of a through pillar.
• Uses: There are many, including partitions and inside walls.

In old Japanese houses, one thick through-stack pillar was used as the "basement," while many tube pillars were lined up in the other parts.Even in modern traditional construction methods, the structure is made up of the combination of the main through columns and the auxiliary tube columns.

3. Corner pillar

The pillars in the four corners of the house are particularly called "corner pillars."Many are through pillars, and are very structurally important.In particular, thicker sizes are often used because they are prone to stress such as twisting during earthquakes.

For more information, please seeThis articleIt's summarized in!

Column cross section dimensions and load calculations seen from an engineering perspective

From here on, we'll go a little further and provide you with quantitative information about the pillars of wooden houses.Even though it's DIY, it's still dangerous to ignore an engineering perspective.

1. Column cross section dimensions

Cross-sectional dimensions of wood that are commonly used in conventional construction methods include "105mm square (so-called 3.5 inch square)" and "120mm square (4 inch square).".Although it varies depending on the region and era, the following are relatively common sizes:

• 105mm x 105mm (3.5 inches x 3.5 inches)
• 120mm x 120mm (4 inches x 4 inches)
• There are cases where 90mm x 90mm pieces are used (although there may be some concerns due to the strength).

When installing or replacing a pillar for DIY renovations, at least 105mm square is often used.It is not uncommon for two-storey homes to use "120mm square" as the main pillars.

2. Wood Strength: Compressive Stress and Allowable Stress

Wood (especially coniferous trees such as cedar and cypress) has various indicators, including compressive strength, bending strength, and tensile strength.Of these, the most important thing for pillars is the "compressive strength."This is an indicator that indicates whether the force is applied from the bottom to the top, and whether it can be supported without collapse.

• For example, cedar wood (water content about 15%) has a compressive strength of approximately 30-40N/mm^2.However, this is breaking strength.
• In actual design, the "permissible compressive stress" varies depending on various standards, wood rank, and dry conditions, such as "7-9N/mm^2" based on the safety factor.

When you ask "what should we use this number for?", you can roughly calculate the "permissible load (N)" by multiplying the cross-sectional area "A(mm^2)" by the allowable stress "σ(N/mm^2)".

3. Simple load calculation image

For example, assume the following case:

• Ingredients: Cedar
• Allowable compressive stress: 8N/mm^2 (assumed)
• Column cross section: 105mm x 105mm → Cross section area is "11025mm^2 (105 x 105)"
• Allowable load supported by one pillar (assuming safety): 11025mm^2 × 8N/mm^2 = 88200N ≒ 8820kgf

*1kgf ≈ 9.8N, so it is a simple conversion.The approximately 8,820kgf can support approximately 8.8 tons.This is a very simple calculation example that takes into account the vertical load only.Of course, in reality, you need to consider the number of beam confluences, joint reinforcement, and aging, so this does not mean that up to 8.8 tons are OK!It is designed by multiplying the theoretical value + safety factor.

However, when doing DIY, it is very important to have an image of, "How much will the estimated weight that can be supported change if the pillar size changes?"

material

How to choose a pillar and what to be careful about

When you think about "preparing a new pillar," many people may be wondering what standards and standards to actually choose the wood.Here we will introduce some key points for beginners, such as JAS standards (Japanese Agricultural and Forestry Standards), how to read grades, whether or not there are knots, and how to use "processed wood" such as plywood and laminated wood.When trying DIY, please refer to the following to see what kind of wood you should buy to be safer.

1. Check the JAS standard

When purchasing wood, you may also see things that are marked "Structural sawn with the JAS mark" or "JAS standard products" at home improvement stores.This is a mark given to wood that has passed the national standards (Japanese Agricultural and Forestry Standards) and guarantees a certain level of quality and strength.

1. If labels such as "Structural Lumber (KD)" or "Structural Lumber (E○○)" are proof that strength and moisture content are controlled.
2. The JAS mark ensures "strength above a certain standard" and "reliable quality."

If you are using it as a pillar for DIY, choose a "product that follows the JAS standard as a structural material" and you will have fewer mistakes.The price will go up a little, but it is not a waste given the safety and reliability of the product.

2. Be careful of the number of chords and appearance

The exterior of the wood may include "knots," "cracks," or "twist."The nodes themselves are not necessarily bad, but the more large nodes there tend to be a lower intensity.Pay particular attention to the following points:

1. Whether there are "too large knots" or "loose knots": Materials with missing knots and holes tend to be worried about their strength.
2. No cracks or twists: It is not possible to use it if there are only a few shallow cracks on the surface, but be careful of deep cracks.
3. Warp and bend: When purchasing from a home improvement store, it is recommended to lie on the pillars side to see if they are straight.

Although it may not be a problem in terms of appearance, if the contents contain too much moisture, they may cause cracking or warping to occur later.As written as "dry material (KD material)", if you choose one with a low moisture content and is controlled, it will be less likely to deform and is easy to use for DIY beginners.

3. How do you use laminated wood or plywood products?

3.1 Laminated material

"Gluorum" is a piece of wood made by bonding multiple wooden boards in parallel to form a single piece of wood.It is characterized by its uniform strength and quality, and is less likely to knot and warp like natural wood.Structural laminated wood, certified by JAS standards, has high performance as columns and can also be used as beams.

• Advantages: There is little distorted (warping and cracking) and there is little unevenness in quality.Easy to process fittings and hardware.
• Disadvantages: If you place importance on the texture of natural wood, preferences vary.The price is a bit high.

When replacing or installing new pillars for DIY purposes, if you want to prioritize "reliable strength" and "stability" rather than appearance, try plywood as a candidate.

3 LVL (single veneer laminate)

"LVL (Laminated Veneer Lumber)" is a product made by laminating thinly sliced ​​solid veneers (like veneers) in the same direction as the fibers, and then bonding them.It is generally used as a "reinforcement for beams and girders," and although it is similar to plywood, it is highly strong.

• Advantages: High strength and stable quality.A wide range of sizes available.Very few warping and cracking.
• Disadvantages: The exterior is industrial and the natural feel of the wood grain is weak.The cut surface looks like plywood.

LVL is often used to reinforce beams and foundations, but there are also types that can be used as pillars.However, it may be a little less workable for DIY use (it may be hard and difficult to cut), and may not be suitable for those who are particular about the appearance and texture.If you can think of it as "strength is important and appearance is secondary," it's worth considering.

In principle, we do not recommend using plywood laminated material (with core material) as pillars.

"Simple laminated materials" made from stacked plywood may not be recognized as genuine structural materials.Some products simply have veneered on the surface, so it is safer to avoid using these as pillars.It might be fine if you just use it as a temporary support when jacking up or use it as a minor auxiliary pillar, but be careful as it is often dangerous to use it as a permanent pillar.

Use according to your purpose

In DIY, the roles you need in pillar materials differ depending on the scene.Think about it according to your purpose as follows:

1. "Use on main structural columns (through columns and pipe columns at key points)"
   • It is safe to say that "JAS standard products made from solid wood (such as cedar and cypress)" or "structural laminated wood" is the best.
   • Choose one with fewer knots and water content.
2. "Use it with reinforced columns or partitioned tube columns."
   • If it is strong enough, solid wood with few knots or laminated wood will be sufficient.
   • It is important to accurately process the reinforced hardware and fittings at the joints with the beams.
3. "Temporary support and temporary pillars"
   • It's okay to use inexpensive SPF material or plywood laminated material from a home improvement store.However, long-term use is not permitted.
   • Don't forget to "set it firmly with your hardware" as long as you'll remove it when you've finished using it.

If you're wondering which one to choose, you'll probably start by consulting with a home improvement store or a wood specialty store, and then telling them, "I want structural grade pillar material," they will often guide you to the appropriate one.

Consider the appearance of the

If the pillars are exposed (such as a pillar standing in the middle of a room), you'd also want to emphasize the appearance and feel of the body.In some cases, there are products called "decorative pillars" that are finished so that the knots and wood grain look beautiful.

• The "solid cypress decorative pillars" have beautiful fragrance and wood grain, enhancing the interior.
• The cosmetic materials that make use of "red cedar meat" are also popular.The flakes can be enjoyed as a taste to a moderate degree.

However, decorative pillars tend to be expensive, and even if the surface is clean, they may have a low strength rank for wood, so make sure they meet both the "standards as structural materials" and "beautiful appearance."

If you are particular about the manufacturer or production area

The characteristics vary depending on the origin of the wood.Some people may want to use domestically produced wood (such as cedar and cypress), while others may prefer structural laminated wood produced overseas.If you are particular about the brand or production area, please consider the following points:

• Manufacturers that publish "water content" and "Young's coefficient (E value)" are highly reliable.
• Using locally produced wood can sometimes result in lower transportation costs.

There's no need to be too particular about the production area on a DIY scale, but if you want to use domestic cypress or local cedar wood, we recommend contacting your local sawmill or construction company.There may be an unexpected bargain.

A summary of points to keep in mind when purchasing

1. Is it recognized as a JAS standard product or structural material?
   • Check the display in store.If you're unsure, tell the store clerk that you want structural pillars.
2. Size of the nodes and whether there are no missing nodes
   • Visually check for large holes or cracks.
3. Water content and dryness
   • KD material (artificially dried material) is less likely to get discouraged and is easier to handle even when using DIY.
4. Appearance preference
   • Should I use it as a decorative pillar or hide it?Consider the balance with the amount.
5. Plywood and simple laminated materials are for temporary use only
   • It is not recommended as a main pillar.Only use it temporarily, such as "jack-up."
6. Processability
   • Solid wood is relatively easy to process, but the knots make it difficult for the blade to pass through.Plywood and LVLs have many hard parts, and the power of the tool may be required.
7. I'll buy a lot just to be sure
   • DIYers are likely to cause a loss of cutting or cracking, so it's safe to reserve an extra spare or have one or two extra spares.

If you're thinking, "I'm going to buy a pillar DIY from now on!", use the points above to see, touch, and take your time choosing your products at home improvement stores or wood stores.If you do your research in advance, you can consult with the store clerk specifically, such as "I'm looking for a JAS standard product for structural use" or "I'd prefer KD material with fewer knots," which should significantly reduce the risk of failure.

This is a summary of how to choose a pillar and what to be careful about.Get the pillars you have envisioned and try a DIY renovation that is safe and satisfying.

Is laminating wood really just a "temporary" use?Learn about its capabilities as a structural tool

Although it is called laminated wood, it actually comes in a wide variety of ways, from "laminated wood for furniture" to "high-strength laminated wood for structural use (gluam)."Many DIY users believe that "laminated wood is weak, so it can only be used as temporary pillars when jacking up," but for structural use, laminated wood has clearly passed the JAS standard, and is actually less varied in quality than solid wood, and has a higher strength and reliability.Here we will explain in detail whether laminated wood can be used as a "pilot" rather than as a "temporary" structure, as well as the basis and points to be careful about.

Big differences depending on the type of laminated wood

Laminated materials for furniture and interior

Many of the shelves made of "pine plywood" and "larch plywood" that are often found at home improvement stores are made for furniture and interior use, and in many cases they have not been tested or certified for structural use.The same goes for what is called "lamin material" or "DIY laminated boards."

• Thickness and adhesive layer specifications do not assume that they are "loaded"
• No JAS mark (structural certification)

These are the characteristics.These are convenient for "use flat" on tables, shelves, and wall constructions, but they can be dangerous to use them on pillars that support the loads of the house.It is safer to use these "non-structural laminated wood" as temporary support materials and support materials for jack-ups.

Structural laminated wood (Groulum)

In contrast, there are "structural laminated wood" manufactured for use in areas that "support a house" such as beams, columns, and load-bearing walls in buildings.This has the following characteristics:

1. Passed strength tests and quality control in the JAS standard (Japanese Agricultural and Forestry Standards).
   • The E○○ (Young's coefficient) and allowable stress are clearly shown, and there is less variation in quality than solid wood.
2. Standards for adhesives and lamination methods to withstand "structural applications"
   • Maintains a high standard of strength and durability.
3. A lineup of relatively large cross-sectional sizes
   • It ranges from so-called "square wood sizes" such as 105 x 105 mm and 120 x 120 mm to large cross sections of 300 x 120 mm or more for beam applications.

In fact, these "structural laminated wood" are often used proudly as pillars and beams in the main building, and are not a problem in terms of strength.Many large-scale commercial and public facilities, and homes other than the 2x4 construction method are built using "conventional shaft construction method + structural laminated wood."

Reason for the image that "laminated wood is weak"

1. Confusing it with furniture laminated boards
   • When you look at the laminated boards and lamination materials in the DIY corner, you will likely find it weak, and you will be misunderstood that if this is laminated wood, it will be weak.
2. There was a problem with the early laminated wood.
   • When laminated wood first began to become popular in Japan, adhesive technology and quality control were not yet as well established, and there were cases where peeling and defects occurred, which has left some people hanging over this image.
   • Currently, these problems have been reduced extremely due to advances in JAS certification and adhesion technology.
3. The wood grain looks more artificial than "real solid wood" and lacks confidence
   • It is clear that the appearance is layered, so you may feel psychologically weak.
   • However, since it is actually made through proper adhesion and crimping processes, the risk of sudden large knots and cavities inside is rather low, and the advantage is that the strength is maintained constant.

Things to note when using laminated wood as a "pillar of the main building"

Structural laminated wood can be used as main pillars, but be sure to check the following points:

1. Is there a JAS mark (structural laminated wood) mark?
   • It is most important to note whether there is a clear statement such as "JAS structural use" or "structural laminated wood (E○○)."
   • It is also effective to directly check at a retailer (such as a wood specialty store or a major home improvement store) and ask, "Can this be used for structural purposes?"
2. Choose the right cross-section size
   • For two-storey homes, the main through-pole use around 120mm square.
   • There are cases where auxiliary tube columns are "105mm square" is sufficient, but this is determined based on the construction standards law and structural calculations.
3. Joint joints and hardware reinforcement
   • In the case of laminated wood, the same method as conventional construction methods is to secure strength using "stitching and mortises + hardware" to join the beams and foundations.
   • Although laminating wood is hard and difficult to process during installation, if you use the appropriate power tools and saw blades, you can process the work without any problems.
4. Preservation and termite treatment
   • Choose antiseptic and termite-resistant products depending on where the pillar is used (where termites are likely to come in, such as near the floor).
   • If surface finishing is required, you can also choose structural laminated wood that has been "painted" in advance.
5. Comparison of cost aspects
   • Laminated wood may be higher than solid wood of the same strength grade, or vice versa.Prices vary depending on the production area, shipping volume, and distribution route, so please compare and consider it.

Summary: Laminated wood is completely different for "non-structural" and "structural"

• "Non-structured laminated wood" for furniture, etc.
  • Suitable for use with low loads, such as shelves and desk tops.
  • It can be used as temporary support materials such as jack-ups, but it is not recommended to use it on pillars that support large loads over the long term.
• "Structural laminated wood" that meets JAS standards
  • High strength, high quality laminated wood, which is also used for through columns and beams in homes.
  • There is less variation than solid wood, and stable strength can be expected.
  • The fitting processing and hardware make it suitable for conventional construction without any problems.

In conclusion, whether or not laminated wood can be used as the "pillar of the main unit" that supports the home itself in DIY depends on the product you choose.If you obtain laminated wood that has firmly passed the structural standards, you can use it with confidence as a high-strength and stable material.On the other hand, inexpensive "furniture laminated boards" and "laminated materials" are not proof of being structural materials, so it is dangerous to use them on pillars that are subject to load.It is important not to collect the ``laminated wood = weak'' all at once, but to select it well according to the purpose, standard and grade.

If you're unsure about using it for DIY purposes, ask a home improvement store or a wood specialty store to see specific questions such as "I'm looking for JAS laminated wood for structural use" or "I want to use it on pillars so what is the strength grade?"Some store clerks may show you specialized materials.This way, you can use laminated timber with confidence, not as a "temporary material" for jack-ups, but as a "permanent material" that firmly supports your home.

Finishing

Presence of termite-resistant agents and other aspects

When choosing wood, it is safe to consider durability and hygiene, not only its strength and appearance, but also whether it is "termite-proofed" treatment.Termites damage in particular is one of the major risks in wooden houses in Japan.Please check the following points:

1. Presence of termite-resistant agents or embalming treatments

1. Pressure injection treatment (ACQ, etc.)
   • This is a method of placing the material in a chemical tank and pressurizing it to allow termite-proof and preservatives to penetrate deeply.It is often used in areas close to the foundation or outside, but it is also sometimes used on pillars.The advantage is that the chemical solution is deeper and more durable.
   • One disadvantage is that it is more heavy than regular solid wood, and may leave a unique color and odor on the surface.
2. Surface coating treatment
   • Although it is not as bad as pressurized, it is a method of applying termite-proof and preservatives to the surface of the wood.Even if you are DIYing, you can apply preservative paints and termite-proofing agents sold at home improvement stores.
   • However, since it is difficult to penetrate well into the interior, the long-term effect tends to be lower than that of pressurized material, so repainting is required regularly.
3. No treatment (no drug use)
   • Some people want to avoid chemical treatment as much as possible, taking into consideration the environment and health.In that case, you can also choose "a tree species that are said to be relatively resistant to termites, such as cypress and cypress (seaweed)."
   • However, since it is not perfect, it is important to take thorough measures to ensure that the foundations, foundations, ventilation and water intrusion routes are taken.

If you are replacing a pillar for DIY, or replacing a pillar near the floor or a pillar near the plumbing area, which is prone to termite damage, it is very worth considering termite-proofed wood.On the other hand, if you are concerned about the smell and chemical ingredients of the chemicals in the visible parts of the room, you can also choose untreated domestically produced materials plus regular maintenance.

2. Selecting wood that suits your location and environment

1. Close to the ground or water
   • There is a high risk of rot, so pressurized materials and structural laminated materials containing termite-resistant agents are safe.
   • Take measures to prevent moisture-proofing sheets, ventilation, and water intrusion routes around the foundation.
2. For interior decorative pillars and partitions
   • If you are looking for good looks, untreated decorative pillars and cypress wood with few knots are popular.
   • If you are going to treat your termites, it's safe to choose a product that has little smell and is designed with the effects on your health.
3. The pillars of veranda and wood decks exposed to the outside air
   • As there is a high risk of rainwater entering, it is better to prioritize pressurized materials or materials that have been treated with antiseptic termites to last longer.
   • The key is to ensure that you do not neglect maintenance, such as regularly overcoating preservative paint.

3 Considering cost and lifecycle

• Pressurized materials and structural materials that have been treated with termites have a higher initial cost than regular untreated materials.
• However, since the risk of early replacement due to termite damage and rot is reduced, there is a high possibility that the total cost will be reduced in the long run.
• Conversely, if you want to keep the initial cost down, you can also use "untreated domestic cedar and regularly apply preservatives and termite-resistant agents."It takes time and effort, but it is easy to prevent serious damage.

What about white wood?

White wood is a commercial name that is mainly used as a coniferous tree such as European spruce (Picea abies)**, and is often distributed in Japan as two-by wood for 2x4 and SPF wood.

• merit
  1. Low price
     Compared to domestically produced wood such as cedar and cypress, or structural laminated wood, it is often available at a relatively reasonable price.
  2. Easy to process
     The soft material makes it easy to cut and drill holes.Some people find it easy to handle even when using DIY.
  3. Lots of circulation
     It is one of the materials that is easy to find at home improvement stores.
• Disadvantages and points to note
  1. Low durability and corrosion resistance
     White wood is compared to cedar, cypress, or European red pine.It is not very resistant to rot or termites.Special care is required in humid places such as outdoors or near under the floor.
  2. Preservative and termite-resistant treatment is essential
     If you use white wood as a pillar, you do not use a proper pressure injection treatment or surface coating of termite-resistant agents.Risk of termite damage and decaywill increase.Even if the 2x4 method is used, if used on the base or bottom structure without embalming, it will often be damaged early.
  3. You need to check "structural" certification
     Home improvement storeSome SPF materials (Spruce-Pine-Fir) and other products are not JAS certified as architectural structural materials.If used in the main building as a pillar of conventional construction methodsIf so,Is there a sign of "Structural White Wood"?It is important to check the following and understand in advance what level of strength you have.
• Conclusion: If you want to use white wood as a pillar, check the location, embalm treatment, and JAS standards carefully.
  • DIY 2x4 wall underneathFor use in other ways, there is not a big problem as long as the indoor space is dry.
  • However, it is not recommended to use it as a main pillar (through pillar or corner pillar) in conventional construction methods, given the risk of decay and insect damage.If you really want to use it,Anti-termite and embalmed structural gradeYou must select and thoroughly implement appropriate construction and maintenance.
  • If you jump just at the low initial cost,Later maintenance costs and replacement risksIt may be high, so we recommend that you consider the overall balance carefully before choosing.

4 Environmental and health considerations

Chemicals used for termite-proofing and embalming treatments may contain ingredients that may cause allergies or health hazards.However, many commercially available products are regulated with regard to the amount of formaldehyde emission, and are sold that meet the safety standards set by law.If you are concerned, check the following points:

1. Product F☆☆☆☆ (Four Star) display
   • It is the lowest level of formaldehyde emission.You can determine to some extent the impact on the room by whether or not this is displayed.
2. Thorough ventilation and maintenance during installation
   • When applying termite-resistant and preservatives, be sure to ventilate sufficiently and wear protective gear to prevent the skin and eyes from getting any chemicals on your skin.
   • Even after installation, open the windows for a while and replace the air inside the room to improve safety.
3. Natural termite and preservatives
   • There are also an increasing number of products that use boric acid-based and natural ingredients.The price is a bit high, but the advantage is that it is easy to incorporate even for people who don't like chemicals.

5 Final decision points

1. "Where should I use it for DIY?"
   • The location, humidity, and whether there is termite damage, are determined and the level of termite treatment is determined.
2. "Would you like to make it last longer, even if it costs money?"
   • Pressurized injection materials and powerful termite-proof and preservatives will increase your long-term peace of mind.
3. "How much resistance to smells and chemical components?"
   • Even though it has been treated with termite, some products are not very resistant to odor.If you are interested, we recommend checking out the in-store sample.
4. "How much are you prepared to carry out regular maintenance?"
   • Even untreated materials can be kept long enough by checking and applying them to the leash.

As mentioned above, the choice of termite-proof and embalming depends on "safety," "cost," "where to use," and "lifestyle (regular maintenance available)."When replacing or reinforcing pillars using DIY, you can protect your precious home in the long term by not underestimating the risks of termites and other things, and by properly disposing them and choosing materials.

If you keep these points in mind, you will be able to choose wood that is more secure, taking into account whether or not there is a termite-proofing agent, difference in durability, and the impact on costs and health.Because it's DIY, take your time choosing materials and aim to create a home that you won't regret.

How to dry pillars and how to deal with cracks

"The better the dryness of wood, the stronger it becomes," and "If the moisture content is high, it will likely deform more rapidly later." Have you ever heard of these stories?In fact, the "drying method" for pillars is extremely important, and even in DIY, the ease of work and finish can be greatly changed depending on the type of pillar you choose.Here, we have summarized the differences between natural drying (air drying) and artificial drying (such as KD material), as well as the "back splitting processing" that intentionally breaks the cracking process for even amateurs.

1 Natural drying (air drying)

Naturally dryis a method of storing wood outdoors or in a well-ventilated warehouse for a long time, and naturally removes moisture.This is a common technique in traditional sawmills, and it is said that taking your time will make it easier for the moisture inside the wood to evenly escape.However, you need to be aware of the following points:

1. Long drying period
   • Depending on the species and cross-sectional area, it may take 1-2 years, or sometimes longer.
2. Uneven drying and cracking are likely to occur
   • As it is affected by the rainy season and seasonal changes, the entire area is not easily dry out evenly.
   • If the surface drys first, natural cracks may occur due to the difference in shrinkage from the inside.
3. The moisture content is not quantitatively controlled
   • As the temperature and humidity vary depending on the outside air temperature, you can only find an estimate of how dry the wood is when you purchase it.

If you are looking to obtain natural drying materials by DIY, it is best to check the "dry years", "storage environment", and "current moisture content" at a sawmill or timber shop.Using wood that is not dry enough as a pillar can cause major warping and cracking after installation, and there is a risk of the fitting being distorted.

2 Artificial drying (Kiln Dried Wood)

• *Artificial drying (KD material)** is a method of placing wood in a special "drying kiln" and forcibly drying while controlling temperature, humidity, air volume, etc.This artificial dry material is the mainstream of today's residential structural materials.The main features are as follows:

1. Achieves stable moisture content in a short period of time
   • Because it is managed in a constant temperature and humidity environment, drying progresses relatively evenly to the inside of the wood.
   • It is common to ship the product after dropping the moisture content to a 15-20% level.
2. Reduces the risk of cracking and warping
   • Is it possible that the sudden drying will increase cracking?It is often thought that this is the case, but recently the drying process has become more sophisticated, and with proper temperature control, it is being made into a product in a state that is less likely to cause major cracks or warping.
3. The quality is stable
   • According to JAS standards, strength and dryness are inspected, and only those that meet quality standards are distributed.
4. Prices tend to be a little higher
   • It costs more equipment and hassle than natural drying, so it may seem a little expensive when viewed at a DIY level.

However, if you want to "process the finish" or "minimise the distortion after work", KD material has the advantage that it will reduce the hassle and prevent problems as a result.

3 What is spinning?

Have you ever seen a column or beam made from wood with a deliberately crack-like notch on the back?This is a technique called "sparking"**.

1. The purpose of the spine
   • To control natural cracking when wood drys out, differences in shrinkage occur between the center and the surface.
   • By inducing cracks in a certain location in advance, it prevents warping and unintended cracking in the wood, and stabilizes the shape.
2. The appearance and strength of the spine
   • At first glance, you may think, "It's not strong because it's cracked," but in fact there are very few major structural issues.
   • Controlled cracks have the advantage of being more predictable and maintaining uniformity than "cracks that don't know when or where they will occur" that occurs after drying.
   • However, the cracks are not completely controlled, and small cracks may occur other than the spine, but it is common for the most part to have fewer problems than those without spine.
3. Things to note when handling DIY spinning materials
   • It is necessary to make efforts to apply it to areas that take appearance into consideration, such as facing the back split surface inward.
   • Consider maintenance such as preservatives and putty treatments as necessary to prevent dirt and moisture from accumulating in the cracked areas.

4 Differences in strength and finish depending on drying method

5 Tips for determining the dryness of pillars in DIY

1. Check the label and description of the drying material
   • Check to see if there are labels such as "KD material" or "dried material" at home improvement stores.Ask the store clerk and they will let you know the availability.
2. Visually check for cracks and warping on the surface
   • Avoid items that have already had large cracks or twists.If you use it forcibly, it will lead to construction problems later.
3. The weight and feel of the touch
   • Of the many woods lined up, extremely heavy items are likely to have a lot of moisture (undried).If you hold multiple bottles and choose a lighter one while comparing them, it will often cause relatively dryness.
4. Understand why there is a spine
   • The back splitter is a product that controls deformation by "deliberately cracking it."If you are using it for DIY purposes, try to adjust the direction you are installing it to make the appearance more stylish.
5. Buy a spare number
   • With DIY, cracks may occur during installation or storage, or machining errors may occur.It's safe to reserve one or two more bottles with plenty of room to spare.

6 Summary: Drying and cracking are important points when choosing a pillar

• Naturally dried material (AD material)
  • This is attractive for those who value the texture of wood using a traditional method.If the material is dried over time, it will not be a problem in terms of strength, but there is a high risk of uneven drying, cracking, and warping.
• Artificial dry material (KD material)
  • It is the mainstream in modern construction houses.It is controlled to a certain moisture content, and there is relatively little deformation problem after installation.Prices go up a little, but they are easy to recommend for DIYers.
• Back split processing
  • A technology that controls natural cracking from the beginning and minimizes distortion.The cracks themselves are not the weakness, but rather the advantage of avoiding large cracks after the house is completed.

When replacing or installing new pillars for DIY, it is very important to consider the materials based on dry conditions and whether or not they have been split.If unexpected cracks or warping occurs after installation, repairs are extremely time-consuming and costly.Just by keeping a close eye on things like "drying methods," "water content," and "splitting," your success rate should be significantly increased.Please try comparing the wood at the store and checking the manufacturer's information to find a piece that you are satisfied with.

Actual DIY work procedure: Reinforcement, replacement, and expansion of pillars

From here, we will introduce some of the most important steps and tips for when you feel like you want to put your hands on a pillar!Please read this while comparing it to the situation in your home.

1. Formulation and measurement

The first step is to understand the current dimensions, materials, and location of the pillar.Check the drawings if there is one, and if there is one, turn part of the wall to check the actual condition of the pillars.

• What is the pillar size?(105mm square? 120mm square?)
• How damaged is it?What about corrosion and termite damage?
• What is the joint between the beam and girder?Is it reinforced with hardware?

Also, it is accurate to use a laser leveler, lowering swing, or level to ensure that the horizontal and vertical position is firmly fixed.

2. Respond to load (temporary support)

When replacing or reinforcing a pillar, it is necessary to take the "load temporarily received by the pillar" elsewhere during work.This is called "temporary support" or "jack support."If you remove the pillars without doing this, there is a risk that the building will temporarily sink, so be sure to do so.

• Poles are set up under the beams and girders near the pillars using architectural jacks and temporary support.
• Apply force up and down little by little to transfer the load on the existing pillar to the support.

It's dangerous for DIY beginners to do this in a rough manner, so please do it carefully.Even a small sinking can damage the interior, so take it carefully and slowly.

3. Removal and repair of existing pillars

Once the temporary support is complete, the existing pillars will be removed and repaired.However, when removing large amounts of data, problems with "structural calculations" or "confirmation applications" may arise, so please consider ways to reinforce the pillars as much as possible without removing them.

• If the damage to the termites is severe, it is recommended to replace it.
• If replacement is difficult, there are options to "enlarge the bulk" or "reinforce the hardware to the joints with the beams and girder."

4. New pillar installation and fixation

When installing or replacing a pillar, please note the following points:

1. Dimensions: Measure the ceiling height and floor level and accurately cut the required length.Even if the error is 1mm, fine adjustments can become difficult later.
2. Processing of joints and fittings: With traditional construction methods, the fittings (tennises and missing parts) with beams and foundations are accurately processed.For DIY purposes, you can simplify processing by using reinforced hardware.
3. Selection of joint metals: There are currently many types of hardware available on the market to reinforce the braces and joints between columns and beams.Use different pillar-based hardware and stud hardware.
4. Jack down: Slowly return the beam raised with the temporary support to its original position, while transferring the load to the new pillar.It's important to take your time and not rush this.

Replacement case: Repairing partial pillar corrosion

For example, if the bottom part is "only 30cm corroded", you can also cut only the corroded part and add new parts.In this case, ensure strength by machining the joints and reinforcing the hardware.

Frequently asked questions: What to do in such a situation?

Q1. "The pillar is slightly tilted... Can you fix it by DIY?"

If the tilt is small, it is possible to reinforce the distance between the beam and the beam with a "plate hardware + short reinforcement column" to slightly correct the tilt.However, if the cause of the tilt is ground subsidence or corrosion of the foundation, fundamental measures are required.It may be beyond the scope of DIY, so consult an expert.

Q2. "I want to remove the walls that are not slidable and create a large space."

It is important to determine whether it is a "just a wall" that is not brilliant, or a "actually a wall of stress resistance."Drawings and current status surveys will require that you check whether the wall is a load-bearing wall and other reinforcements to ensure earthquake resistance (for example, new braces or structural plywood are attached).

Q3. "I want to add one pillar to reinforce it"

It's a simple reinforcement, but you should think about whether it's really necessary.Increases the load will change the balance, and in some cases, the burden will be put on other pillars.If you are going to do this, you will also need to check whether the existing beams and foundations are sufficient.If you are unsure, consult an architect or something.

Q4. "I want to repair a pillar on the second floor, but I don't know what it is related to the through pillar on the first floor."

The procedure will vary depending on whether it is a pipe column on the second floor or a through column that extends from the first floor.Start by opening the wall or entering the attic to understand where the pillars actually extend from and from what point they are.If you cut the pillar on the second floor without any hesitation, it will affect the first floor as well.

Summary

In Japanese wooden houses (up to two stories), "pillars" are the skeleton of the house.In particular, "through pillars" are important to support the loads of one or two floors, so caution is essential when handling them in DIY.Even if the names are changed, such as "tube pillars" or "corner pillars," each person plays a role in supporting the entire house.

Furthermore, even if it's DIY, work related to "structure" always comes with building standards laws and safety issues.In particular, be sure to keep the following points in mind.

1. "Understanding the structure of the entire house" is the top priority.Check the drawings and open the wall to find out which pillars are where.
2. We will have as many "an engineering quantitative perspective as possible."It focuses on basics such as the cross-sectional area of ​​the pillar, the allowable stress of wood, and the load receiving flow.
3. During work, the load is changed using a "temporary support."Use a jack to transfer loads in stages, replacing and reinforcing the pillars.
4. Appropriately "reinforcement of fittings and hardware" at the replacement and reinforcement areas.Even if you are using a DIY connection, you can increase your peace of mind by using a dedicated hardware for joining.
5. If the structure is affected significantly, consult an expert.Be especially careful when removing the load-bearing walls and reinforcement with large scale.

It may seem difficult at first glance, but if you keep track of the basics, you can expand the range you can do with self-renovation.However, please be sure to "safety first" and "compliance with legal procedures.""Reliably researching areas you don't understand" and "If you think it's impossible, ask a professional" seems like a detour, but in the end it's the path to keeping costs the most.Let's take on DIY smartly to protect your precious home!

References and Videos

• "Structure of Wooden Houses" Japan Housing and Wood Technology Center
• "Manual for Wooden Pole Framework Construction Methods" Japan Two-By Four Architectural Association (the names are similar, but there are cases where traditional construction methods are also handled)
• "An example video of earthquake-resistant reinforcement using conventional construction methods" YouTube channel/Various creators related to renovations and DIY (with respect: The wisdom of DIY enthusiasts is really helpful)

If you are unsure about the details or practice, please consult an expert (carpenter, architect, renovation company, etc.).DIY is a lot of fun, but the safety of yourself and your family is more important than anything else.I sincerely hope that your DIY renovations will work out!

In the first place, how much can I do to renovate my home?Where should I start?In other words,Herefrom.If you would like to know more about the specific renovation process and construction,HerePlease also take a look at the page!

About the pillarArticles about this structureThere are also.