Hello everyone, this is DIY Renova.
When you are undergoing full renovations or skeleton renovations, you may find yourself stumbling around, "when should I ask for pipes and wiring?", "how far is the range that can be done with DIY?", and "what order should I do less and less redo it?"

In this article, we will explain the following: "water, gas, electricity, and internet (light)" based on the premise of a detached wooden house.Request timingandMaterials to prepare,andSchedules from requesting a quote to completion of constructionWe have organized this in a concrete way so that even first-time users don't get confused.

If you're wondering "How much renovation or remodeling can I actually do on my own home?" or "Where should I even start?", please visit this page. If you're looking to learn more about specific renovation processes or construction details, don't miss this page as well!

The parts emphasized in "" are important points that are likely to cause problems on-site. This is written based on the premise of Japanese laws and the operation of local governments, so please check the latest rules for the relevant local governments in the final review.

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Estimated conditions and how to use this article

• Target: Japanese wooden detached houses (up to 2 floors), fully renovated and large-scale renovations of existing homes
• Involvement of clients: While mainly DIY, we ask for "parts that should be requested by professionals" for legal and safety reasons.
• Goal: Process control that minimizes redo and optimizes construction time and costs

This article consists of the following: "Broadscape → Quick Reference Table → Details of each type of work → Template materials → Checklist → Frequently Asked Questions → Summary." We can use it in practical use even if we browse only the necessary parts.

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Overall picture: Three waves: “preceding,” “parallel,” and “pre-finishing”

The infrastructure of renovations is divided into three major waves across time.

1. Preliminary phase (immediately after demolition to underfloor/foundation repair period)
   We will proceed with designing advance water and gas pipes, outdoor retraction, and determining meter positions.
   The "time when the floor is open" is prime time.
2. Parallel phase (structural repair - insulation and airtight - front of board)
   We concentrate on airtight treatment of the main lines and branches of electricity, weak electricity (LAN, TV, sensor) pipes, and through portions.
   The golden rule is to route all cables and piping before installing insulation and drywall.
3. Pre-finishing phase (board completed to before crossing)
   We will summarize the procedures for installing fiber optic lines, installing equipment in general, various tests and inspections, and opening, receiving power, and gas flow.
   "End everything before wallpaper and painting" there is no turning back.

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Quick reference table for request timing (estimated skeleton renovations for detached houses)

Production type	When should the landlord first contact you?	Main periods of actual construction	Important points for finishing	Estimated lead time
Water (water supply, hot water supply, drainage)	Immediately after the demolition plan was decided	Underfloor open/In between foundation repairs	Inspection port and header position, pipe heat retention	2-4 weeks
Gas (city gas/LP)	Immediately after the demolition plan was decided	Underfloor open + parallel with exterior construction	Meter position/exhaust top separation	3-6 weeks (longer due to road usage)
Electricity (main line, branching, weak electricity)	If you can see the floor plan confirmed and furniture arrangement plan	Insulation/front of board	Distribution board capacity, circuit division, airtightness of through-port	2-4 weeks
Fiber fiber line (Internet)	Once the location of the exterior walls and indoor information panel is decided	Board completed ~ Before the cross	Piping reuse/new installation, secure ONU installation location	1-3 weeks

"Lead time" is an estimate from on-site survey reservations to construction start. The busy period (end of the fiscal year, around the long holidays, and the New Year holidays) will be even longer. Be especially lenient for gas involving road occupation and mains investigations.

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Laws and regulations that must be followed in Japan and scope of DIY possible (common assumptions)

• Water supply: There is a "designated water supply equipment construction company" system,Designated contractors for meter-related and water supply equipment constructionThe basics are. As handling of the secondary side differs depending on the local government, advance confirmation is required.
• Gas: city gasRegistered business operatorsis installed. Even if you connect to the secondary side, safety checks and leak tests are required.
• Electricity: Wiring work for general-purpose electrical workElectrician qualification is required in principle. Except for inserting and connecting equipment, we will ask a professional to install and extend the wiring inside the wall.
• Communication: Fiber fiber fusion and connector processingThe construction manager etc.. You can DIY your home's LAN, but you will need to adhere to the basics such as fire resistance, airtightness, and bending radius.

"What you can do with DIY" can be used to fix the fixture, root leveling, installation of inspection ports, LAN wiring, and wires for protective tubes.Auxiliary workIt is safe to keep it in.

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Plumbing: Set a "route and inspection port" while the underfloor is open

Criteria for determining the timing of requests

• We start consultations as soon as we see the underfloor and foundation repair process.
• Kitchen/washroom/bathroom/laundry/toiletWhen the final position is 80% fixedDrawing.
• If you use the header method,Header position and inspection portDecide first.

Materials to prepare in advance

• Plan view (A3 recommended): Equipment position, wall core dimensions, floor height
• Specifications Notes: Piping material (e.g. cross-linked polyethylene), heat retention thickness, airtight method for penetrating floors (e.g. foamed urethane + airtight tape)
• Photo: Meter box, retraction route, current status under the floor
• Desired construction period: Week to ask for on-site survey and date to start construction

DIY can/can't do it

• Can be: Leveling out the pipe route, installing inspection ports, installing protective sleeves, positioning the fixture side
• Difficult: Meter related, main construction of underfloor plumbing, pressure tests, and local government inspection arrangements

Quote Request Template

株式会社〇〇設備 御中

My name is ○○, and I'm currently working as a fully renovated detached house. Regarding water supply, hot water supply, and drainage renewal work,
Can you please provide a site survey and estimate under the following conditions?

・Building: 2nd floor wooden floor, approximately 93 m2 (built in 1980)
・Construction area: meter secondary side update, header type, 5 pieces of equipment (kitchen, bathroom, washbasin, laundry, toilet)
・Specifications: Cross-linked polyethylene pipe 13A/20A, heat retention thickness 20mm approximate
・図面／写真：PDF添付
・Preferred: Currently in the week of ◯, construction begins after ◯,

Please provide an estimated cost and construction period. Thank you very much for your cooperation.

The day's schedule and inspection

• A subfloor inspection port is secured near "just above the header" (easy to maintain in the future).
• The penetration part is treated as a set of "fire-resistant and airtight" (air leakage = risk of condensation).
• Pressure tests are conducted by a contractor. The owner isExplanation of exam time and passing criteriaI will record it.
• In winter, in preparation for freezing, avoiding external exposure of pipes and continuous insulation is attached to terminal tape.

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Gas work: Early confirmation of the meter position and exhaust top separation

Criteria for determining the timing of requests

• Once the demolition plan is finalized,Meter position, water heater position, and exhaust top separationI'll see first whether it can be protected.
• city ​​gasMain pipe location and road useThe overall construction period depends on whether or not there is a

Materials to prepare in advance

• Layout/elevation: meter location, water heater height, separation from windows and ventilation holes
• Notes on whether or not there is a main pipe: Mains status on the front road (if you don't know, check it by field survey)
• Estimated heat of equipment used: water heaters, stoves, (future) heating equipment, etc.

DIY can/can't do it

• Possible: Examination of equipment location, reinforcement of base and supporting hardware, preparation of penetration position
• Difficult: Outdoor retractable pipes, meter-related, airtight testing, gas flow procedures

Quote Request Template

XX Gas Co., Ltd. Construction staff

We request a quote for city gas retraction and indoor plumbing work in connection with detached house renovations.

・Site: ○○ City (2nd floor of wooden building)
・Retractable length: Expected to approximately 15m (site boundary → meter)
・Equipment: 24-inch water heater, built-in stove
・Drawing: Arrangement and elevation view included (PDF)
・Preferred: Please also provide an estimate period if the current situation and road occupying is required in the week of ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯, ◯,

Thank you for your confirmation.

Things to note when hiking outdoors

• If road occupation involves application and permissionOver a monthtoo. The schedule is designed with plenty of room to spare.
• The pipeline has been selected to have a depth and route that is unlikely to intersect with other lifelines, taking into account future exterior construction plans.
• Meters and water heaters are "separated" from the windows and air intakes. We also take into consideration the effects of noise and exhaust rooms.

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Electrical work: Thermal insulation and the "correct timing" is unique in front of the board

Criteria for determining the timing of requests

• In addition to the floor plan,Location and furniture arrangement of large appliancesIf you can see it, start the consultation.
• First determine the main capacity (e.g. 60A to 100A) and the number of circuits for the distribution board.Dedicated circuitAllocate (induction, air conditioner, EV, etc.).

Materials to prepare in advance

• Load calculation note: Number of 200V equipment, over 1500W equipment, and room for future expansion
• Outlet layout: Height (generally around 250mm above the floor), equipment use
• Lighting Plan: Downlight Rail Switch Circuit
• Weak power plan: LAN (Cat6A recommended), TV, door phones, sensors

DIY can/can't do it

• Can be done: LAN wiring, information panels and rack preparation, equipment installation base, and installation of PF pipes for wired connections
• Difficult: New and extension of distribution boards, indoor wiring, breaker work, grounding work

Quote Request Template

XX Denko Co., Ltd. Gochu

Please provide a current estimate and estimate for electrical equipment construction.

・Main contract: Single-phase 3-wire 60A → 100A desired
・Distribution board: 24+2 circuits (with ELCB)
・Special circuits: IH200V, air conditioner 200V x 3, EV200V, microwave, washer and dryer, etc.
・Weak Electric: LAN Cat6A (3 wired rooms), 2 TV systems
・Drawing: PDF attached (including furniture arrangement and lighting proposal)
・Preferred: ◯◯◯◯◯◯◯◯◯◯◯◯◯◯◯◯◯◯◯

Please provide an estimate and a process outlook.

Key points on the site

• All circuits are wired in front of the board,Airtight treatment of penetration partsCompleted at the same time.
• Minimize the exposure length and the metal edgesBushing/protectionBe sure to do it.
• The circuits are divided into "kitchen," "water-based," "air-conditioning," and "information," and the labels inside the panel are clearly defined.
• It's easier to expand by leaving one or two empty pipes (PF25 and 28) for future use.

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Internet (light): Determine the position of the exterior wall penetration and information panel first

Criteria for determining the timing of requests

• Exterior wall specifications (siding/painting) andPenetration positionApply once you have decided where to install the ONU in your home (information panel or inside a storage room).
• If you already have TV plumbingdiversionAlso consider (line transfer and cleaning if necessary).

Materials to prepare in advance

• Photo of the exterior wall: A clearance from the gutters, eaves and sashes
• Home photo: Shelf and information board with ONU and hubs
• Piping notes: presence or absence of existing CD pipes/PF pipes, number of bends, sense of distance

A word note when applying (in the online application section)

• "The exterior walls can be penetrated by ceramic siding. The ONU inside the house is installed on the first floor storage area. We would like to reuse existing TV pipes for outdoor wiring."

Key points on the site

• Outdoor wiringClosed raintop priority. Drip loops on the rising parts, and careful sealing on the penetration parts.
• ONU, hub, router, backup power supplyCan be placed togetherShelves and information boards.
• To avoid blind spots from Wi-Fi in the home, use LAN wired devices.Mesh APThe plan is effective.

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Tips for integration of processes: "Finish in one go" with the same holes and grooves

1. Shared trench (outdoor)
   While following the rules for distance and depth for water and gas, if you divide the layers with the same excavation, you can reduce construction periods and costs. The location was decided at a "on-site meeting" with related companies present.
2. Penetration plan (indoor)
   electricity and light electricitySeparate pipesis the principle. The purpose is to avoid noise and to separate safety. The idea of ​​leaving empty pipes for the future is effective.
3. Testing, opening and receiving power will be made on the same day
   If you open the water supply, apply for power reception, and confirm the gas flow on the same day, you will only have to be present once, reducing the cost of revisiting.

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Checkpoints for estimation comparison (template table)

Perspective	Company A	Company B	remarks
Construction scope (including/not included)			Examples: fill-in-the-blank repairs, scaffolding, industrial waste
Material Specifications			Pipe type, cable standard, heat retention thickness
Rework (guarantee)			◯ years after construction, equipment will be treated differently, etc.
Construction period			Construction begins ◯ days, inspection and examination dates
Conditions for additional costs			Alternative for underground obstacles and impenetrability
Payment terms			Ratio of starting funds, interim and complete funds

Negotiations to reduce "overseas expenses"Car parking arrangements and materials delivery cooperationIt would be realistic to propose support from the client.

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How to write request email/chat (common template)

Subject: ○○ City ○○ Renovation of detached house 〇〇 construction Request for quotation (Request for actual work: ◯ month ◯ week)

△△△ Co., Ltd. (Mr. △△)

nice to meet you. My name is ○○ and I am currently renovating a second floor wooden building in ○○, ○○ city.
Please contact us for an on-site survey and quotation based on the following conditions.

[Building] Built in 1958, wooden 2nd floor, total floor space approx. xx㎡
[Scope of construction] (Water/Gas/Electricity/Light)
[Drawings/Photos] PDF attached (plan, elevation, current situation)
[Preferred time] Current construction in ◯ month ◯ week, construction to start after ◯ month ◯ day
[Points to note] There is an opening under the floor / External wall is not finished / Request for construction at the same time as other construction, etc.

We apologize for the inconvenience, but we would appreciate it if you could reply with an estimate of the cost and the outlook for the process.
Thank you very much for your support.

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Checklist that can be used on-site (printing recommended)

common

• Bring drawings and process sheets in A3 size
• Consolidated contact points (representative contractor or client)
• Neighborhood greetings and sharing work hours
• Pre-order fire-resistant and airtight materials for the through portions

Water

• Determining header position and inspection port
• Continuity of heat retention in the freeze risk section
• A photo of the pressure test attendance and record

gas

• Explicitly state the meter position and check the separation
• Exhaust top direction and height
• Notes on whether roads are occupied and period

Electricity

• Final confirmation of distribution board capacity and circuit table
• Controlling separate pipes and bending times for weak electric power
• Save labels and systematic diagrams in the panel

light

• Water resistant treatment at the outer wall penetration position
• ONU, hub and power supply layout
• Confirmation of line transfer when reusing existing pipes

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Failures and workarounds

• "I stuck the board first and the line route was gone."
  →In advanceAll circuit wiring → Airtight treatment → Photo storageTo finish it until.
• "There is not enough space for the water heater exhaust, so the location and model are changed."
  →The windows, ventilation holes, and boundaries are dimensioned using elevation views and remeasurements are made on site.
• "The area around the meter and information board is unmaintainable."
  →Forward/left and rightservice spaceEnsure that the inspection port is placed close by.
• "The LAN is bent too much and I can't get any speed."
  →The LAN has a large bending radius, and the staple fixing isSlowly. Cat6A recommended.

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Estimated cost (width/reference)

• Water (renewals at home, 5 pieces of equipment): 200,000 to 600,000 yen
• Gas (house + 1 unit of equipment, excluding draw): 100,000 to 400,000 yen (large variation depending on road occupying and mains)
• Electricity (distribution board update + circuit addition + weak electricity): 200,000 to 800,000 yen
• Light (new retractable and small home wiring): 10,000 to 50,000 yen (may be 0 yen due to business campaign)

Not only "initial cost"Future expansion/maintenance costsComparing the "lifecycle costs" including the above will reduce your regrets.

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Tips for client payment and recommended purchase checklist

The client's payment is effective in "optimizing equipment prices."Not covered by construction warrantyorInstallation incompatible due to differences in model numberPlease note that this is likely to occur. Below are some examples of what is suitable for payment.

• LAN cable (Cat6A or higher, indoor use/required length + allowance)
• Information board/19 inch mini rack/shelf board
• PF tube (25/28), wire wire, cable tag
• Bathroom and washbasin stop valves and cosmetic covers (confirm dimensions compatibility)
• Door phone parent unit/sub monitor (confirm wiring terminal specifications)
• LAN cable Cat6A 100m roll (for indoor use)
• PF tube 28 (10m)
• Conduit wire 20m
• Cable tags and distribution board label set

*Please check the stock and price of each shop before installing the actual link.

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Seasonal factors and small tricks to schedule

• Winter: Freezing/snowfall, early sundown →Thermal installation and work timeReserve the amount
• Rainy season: Outdoor perforation and painting postponed →Light and external wiring are pushed forward.
• Obon, New Year's holidays, end of the year: shortage of craftsmen →Reserve 1-2 months in advanceBased on the basics

On-site surveys are often sent early if you are on weekdays morning (slightly transported by contractors).

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Legal and Safety Notes (Amateur-friendly)

• Water supply: The "designated contractor" system is a system that protects safe water (prevents backflow and leakage using inappropriate materials and connections).
• Gas: To avoid explosions and carbon monoxide accidents, all processes are managed from construction to inspection (exhaust and ventilation are required).
• Electricity: Since the human body is sensitive to electricity, wiring and grounding are carried out using systematic standards (protected with breakers and leakage circuit breakers).
• Communication: The light is made from fine glass fibers, and the cutting edges can cause damage to the eyes and skin, so the installation is done by experts.

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FAQ

Q. Which company should I get a quote?

A. To compare three points: "price", "construction method", and "communication".At least 2 companies. If you are in a hurry, please limit it to one company with a proven track record.Specifications are clarified by the hostIt is also effective to prevent shaking.

Q. What are the tips for shortening the construction period?

A. At the "Current Meeting"Shared trench and penetration simultaneouslyagreed. If the process meshes, it can be shortened all at once.

Q. How do you avoid disputes with the client's payment?

A. During the estimation stage, share the "Product List (model number, quantity, delivery date)" and agree to the "replacement and cost burden in the event of non-conformance."

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Summary (Please remember this before going home)

• “Water and gas come in contact with under the floor and exterior structures.Advance phaseI'll decide."
• "Electricity and weak electricity are insulated and in front of the boardThe only correct timing”
• "Light is the front and back of the board, the exterior wall penetration and the information panel.Location is confirmed first”
• "The idea of ​​completing the same hole and groove in one go" will instantly optimize construction periods and costs.

First prepare the processes and drawings, and ask a professional to ask you wherever you want to ask. DIY is limited to the range that can guarantee safety and quality. This basics alone can avoid 80% of the troubles. I hope that your renovations will go safely and comfortably.

If you're wondering "How much renovation or remodeling can I actually do on my own home?" or "Where should I even start?", please visit this page. If you're looking to learn more about specific renovation processes or construction details, don't miss this page as well!

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Appendix: Example Gantt Chart (Images of the standard process for 12 weeks)

week	Key tasks	The client's movements
1–2	Dismantling	Drawing confirmation and current request from each company
3–4	Basic and Structural Repair	Water and gas advance pipes and meter position confirmed
5–6	Underfloor plumbing and outdoor retraction	FIX: Electricity Circuit Table and Weak Electric Plan
7–8	Insulation and airtight	Electrical wire and penetration airtight completed, photo saved
9	Gypsum board	Optical piping wiring and information board preparation
10	Before finishing	Light retraction, fixture installation, water pressure, insulation, leak test
11–12	Finishing	Check before delivery, powering, and gas opening

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References and videos (titles omitted)

• Ministry of Land, Infrastructure, Transport and Tourism Housing Renovation Guidelines
• Water supply and sewerage bureau of each local government “Water supply equipment construction designated contractor system” materials
• Ministry of Economy, Trade and Industry and Electrical Safety-related Organizations "Fundamentals on General Electrical Works"
• City gas companies: "Guide to Gas Equipment Construction" and "Considerations on Standards for Separation of Outdoor Equipment"
• Home appliance construction YouTube: Basic explanation videos of piping and wiring at the site (header method, expansion of distribution boards, how to make information boards, etc.)