"It's impossible to replace the roof yourself, right?" I often hear these things.However, the tatehira roof (tatehirabuki) is a simple structure that connects metal plates together with each other, making it a perfect match for DIY.Moreover, the material is rust-resistant galvanized steel sheet (e.g., NISK Color Pro), which reduces long-term maintenance costs.In this article, we will explain everything from specific quantities calculations to safety measures, necessary tools, installation steps, engineering checkpoints, and cost estimates with the goal of "reading this page alone."

So, here you go.

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What is Ridge-Hiroki?

• Construction Method Overview
  • A Straight Drainage System Is Made By Placing A Metal Plate (0.35-0.5 Mm Thick) In The Longitudinal Direction, And Each Sheet Is Ribs (Gobytes) Are Set Up To Allow Rainwater To Flow.
  • Without Using Screws Or Goby Fastening Machines At The Joints, The Sides Of The Panels Are "Fitted" With One Touch, Making The Installation Speedy Installation.
• merit
  1. It Is Lightweight (Around 3.5 Kg/M²) And Has A Small Load Burden On Wooden Beams And Rafters.
  2. The Joints Are Only Vertically; Zero Horizontal Joints.It Is Also Resistant To Side-Beats And Rain During Typhoons.
  3. Long Lifespan Of Galva Steel Sheets (25-Year Perforated Warranty And 15-Year Coating Warranty (Nisku Color Pro)).になったんです。 English: The First Thing You Can DoNippon Steel Niscs
• Disadvantages
  • If The Slope Is Gentle (Below 1/100), There Is A Risk That Rain Will Flow Backwards.The Minimum Slope Is 1/30.
  • Because It Is A Metal, Sound Insulation And Heat Insulation Must Be Taken On The Base (Sound Insulation Sheet + High-Performance Glass Wool, Etc.).

In Other Words, There Are Basically Fewer Disadvantages Than Other Roofing Materials, Making It Easy To Install And It Can Be Said To Be A Diy Installation Method!

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Other representative metal roofing methods and selection criteria

Construction method	Features	Case Facing	Comparison With Standing Roof
Thatched Roof (Tier Roof)	The Joints And Design Shading Are Strong Horizontally.	Gradient 2/10 Or More, Design-Oriented	Construction Difficulty Is A Little High
Folded Roof	Machine Bends Thick Plates Over 0.6 Mm To Make Them Strong	Factory And Stores, Etc. Are Over 9M In A Span	It'S Heavy And Not Suitable For Homes
Tile Stick	Traditional Metal Roof Covering The Vertical Stone	Maintaining The Design Of Old Japanese Houses And Townhouses	Rippei'S Water Stopper Is Higher Than The Water Stopper Of The Goby Section.
Clay Tiles/Slate	High Heat Storage And Design	Except For Heavy Beams And Cold Regions	Metal Plates Are Advantageous For Earthquake Resistance Loads.

How To Choose

• "Existing Roof Structure": The Healthy Roof Plywood And Rafters Are Used, And The Lower The Load, The Better The Vertical Roof.
• "Slope": A Gentle Slope From 1/30 To 1/5 Can Be Raised Or Folded Plates, And Horizontal Roofing Is Ok If It Is 2/10 Or More.
• "Design": For Straight Modern, For Ridge-Like Style, For Step-Shading, For Horizontal Roofing, For Tiles, For Japanese Style.

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Required tools and materials checklist (general 2F 7 m x 5 m gable roof example)

Category	Product Name	Specifications And Approximate Quantities	Supplement
Main Materials	Lid-Plane Panel (Nisku Pro)	Length 7M X Width 333Mm X 22 Sheets	Width Function 333 Mm, Required Width 7 M → 22 Sheets (Rest + 2 Sheets)
Under Roofing Material	Modified Asphalt Roofing	1 M X 20 M Rolls X 2	Heat Resistant To 110°C Or Higher Recommended
Work	36 X 14 Pieces Of Arabesques And 10 Pieces Of Sheet Metal	1 Bottle = 1.82 M	At The Eaves + Actual Measurements ÷1.82
Cap	Retrofitting Small	Number Of Goby = Number Of Panels	Tip Waterproof
Snow Stop	Eterna 200 Type	15 In One Row	Areas Under 0.5M Of Snowfall
Bis	Stainless Steel Φ4.2×45 Mm	500 Bottles	22 Rafter Pitches Per Piece
Tool	Impact, Angle Wave Cutting Scissors, Deposits, Chalk, Goby Stove	–	No Goby Clamping Machine Required

What you need

Cleavage board

Arabesque 36 / Arabesque 45

What Is Arabesque

"Arabesque" Is A Type Of RoofSheet Metal Parts Attached To The Eaves (End Of The Wife'S Side)This Is An Important Part Used To Prevent Rainwater From Entering And To Keep Roofing Materials Neat.To Find The Required Number, Follow The Steps Below!

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Steps to count the required number of arabesques

① Measure The Length Of The Roof Eaves

First, The RoofThe Length Of The "Eave" And "Keraba" Of The Outer CircumferenceMeasure.

• Elephant (Nagashi): Side With A Gutter
• Keraba (Wife'S Side): The Diagonal Edge Of The Roof

Example:

• Eve: 7M In Front And Back (X2) = 14M
• Karaba: 5M On The Left And Right (X2) = 10M Total: 24M

② Check The Length Of The Arabesque

According To The Product Page, One 1820Mm (=1.82M).

In Other Words,Approximately 1.8M Per BottleCan Be Covered.

③ Total Length ÷ 1.82M = Number Of Required Pieces (Rounded Up)

In The Example Above, Calculate:

24M ÷ 1.82M ≒ 13.18 Pieces → 14 Pieces Required

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Petite Advice

• Considering Joints, Cut Losses, And Stacking Fees,Order 1-2 Bottles With Plenty Of Time To SpareIt'S Safe.
• At The EavesSometimes Arabesques Of Different Shapes Are UsedSo, Check The Specifications Before Ordering!

Small

References And Sources

https://machiyane-mito.com/works/20230727_hokota-tatehirabuki-fukikae_izumi.html

https://nono-s.com/case/11

Ki-Rithei 333/25

https://www.guild-design.com/tag/立て平葺き

What Part Is This?

• Official Name Simple Line (Kango Thatched Roof) "Oguchi".It Is Also Called A "Eave Cap" Or "Sambana" By Manufacturers And Craftsmen.* "Earth" Is The Roof Term "Cut/Edge" And Refers To The Cut Surface Of Sheet Metal Material.Ishikawa Shoten

Where On The Roof?

• Position A Standing Roof At The Eaves (The Bottom Where The Rain Is Flowing Down), Close The Tip Of The Rising Goby (Rib) It'S A Part.
• Role
  1. Block The Goby'S Cavity Prevents Rainwater, Snow, Insects And Fallen Leaves From Entering
  2. Protects The Tip From Wind Pressure,Prevents Flipping And Floating
  3. Hide The Edges Finishes The Look Neat(Makeup Cap)
  4. There Are Also Types That Have Drain Holes And Drain Moisture That Has Accumulated Inside.Roof Repair Master

Is It Necessary?– Conclusion:"Recommended" But Essentially Essential

Case	Needless To Say That The Ending Edge Is Necessary	Reasons And Supplements
Standard Vertical Roof (Eaves Can Be Seen As They Are)	Almost Essential	It Is Waterproof, Insect Repellent, And Wind Damage Prevention.It Is Often Included In Manufacturer Warranty Terms.
The EavesCompletely Covered With A Casque Or GutterSpecial Delivery	It Is Optional But Needs To Be Considered	If The Edges Are Designed Not To Be Exposed To The Outside Air, Some Craftsmen Just Omit And Fold The Goby And Do So.
Diy, Just Fold It Back And Caulking	It'S Not Impossible	However, It Is Safer To Wear A Ready-Made Cap As It Reduces Its Appearance And Durability.

point

• Two Gobys Per Roof Panel ⇒ Caps Are At 1 Eaves X Number Of Goby Preparation.
• The Retrofit Type Is Inserted After The Panel Is Roofed Up And Fixed With Blind Rivets Or Small Screws.Sekino Kosan
• The Color Does Not Stand Out If You Choose A Color Similar To The Roofing Material (Such As Brown, Black, Silver, Etc.).

Summary

• What?A "Rear-Mounted Edge (Eave Cap)" That Covers The Edge Of The Vertical Roof Of The Goby.
• Where?Goby Tip At The Eaves.
• Is It Necessary?From The Perspective Of Waterproofing, Wind Resistance And Design, There Is No Way To Wear It.It'S Almost Essential, Especially When The Product Is Recommended By The Manufacturer.

Even If You Are Diy, Installation Is Easy As You Simply Insert It And Screw It In.It'S Safe To Remember To Arrange It Along With The Roofing Material!

(Option)Snow Stop Fittings Eterna

People Living In Snowy Regions Will Need A Snow-Cable Eterna Metal Fitting.

Engineering Points

• The "Screw Pull-Out Strength" Is Approximately 1.2 Kn Per Unit (N Value Equivalent When Stainless Steel Drill Screw Φ4.2 Is Fixed To A 24 Mm Thick Field Base Plate + Body Edge).Even With Wind Pressure Of 0.5 Kn/M², The Pitch Is 300 Mm, Resulting In A Safety Factor Of 2 Or Higher.
• Bending Rigidity Ei With A Galva Thickness Of 0.4 Mm≒6.8 X 10⁻⁶ Kn·M²/M.Many Reports Of Actual Measurements Have Been Reported, With Field Spacing Of Less Than 450 Mm, Which Means That The Deflection Of The Walking Distance Is 1/250 Or Less.

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Pre-Planning Before Diy

Step A: Ensuring Safety Equipment

1. Scaffolding: In Accordance With The Occupational Safety And Health Regulations, Single Pipes And Mesh Sheets Are Required For Heights Of Over 2M.
2. Full Harness: Under The Revised Act (2019), It Is Mandatory To Wear It If You Work More Than 2M.
3. Weather: Wind Speeds Above 10 M/S Are Cancelled, And Temperatures Above 35°C Are Prevented From Heat Stroke.

Step B: Structure Check

• Check Rafter Size: 105 X 45 Or Higher Is Recommended.
• Rafter Pitch: Standard Length Of 303 Mm Or 455 Mm.Replace Rot And Ant Damage.
• Removal Of Existing Roof Materials: Old Slate Containing Asbestos Is Arranged To Be Collected In Accordance With The Industrial Waste Act.

Step C: Quantity Calculation And Material Ordering

1. Actual Measurement Of Effective Roof Width X Depth (Sketching Is Required).
2. Calculated The Outer Circumference Length Including Arabesque, Cladding, And Ridge Wrap.
3. Any Fractions That Cannot Be Divisible By 1.82 M Always Have A Round-Up + 1 Allowance.
4. Direct Shipment From The Manufacturer Is Over 4M Long And Treated As A Large Shipping Service = Additional Shipping Fees.Choose Between Two-Part Fittings Or Unique Vehicle Arrangements.

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Stand-Alone Thatched Roof Construction Flow (7Th Day Model)

Step 0 Preparation (Day 1)

• Remove Existing Roofs And Remove Scrap Materials.
• Increased The Field Base Plate (12Mm Coniferous Plywood With N50 Nails @ 150 Mm).
• Roofing: 150 Mm Stacked From The Eaves, Staples @ 200 Mm.

Step 1: Installation Of Arabesques And Keraba (Day 2)

1. Arabesque 36 Is Fixed To The Eaves With Stainless Steel Screws @150 Mm.
2. The Sheet Metal Is Then Fitted With A Spacer (12 Mm) So That It Is Flush With The Top Of The Ground.
3. The Joints Are Stacked With Sealing + 25 Mm.

Step 2: Main Panel Installation (3Rd To 5Th Day)

• "Large" Is The Standard If You Choose To Set It Up.The Choke Line Runs Through The Center Of The Width Of The Work.
• The First Sheet Is Set Up And Bending The Side, Then Secured With Screws.
• From The Second One Onwards, Press The "Kangu" Section From Above To Lock The Next To Each Other, And Close The Goby By Hand.
• Screws: 4 Rows X Pitch 300 Mm Per Panel At Rafters.
• Expansion And Contraction Measures: The Long Hole Washer Only On The Eaves Ensures A Sliding Movement Of ±5 Mm (Galvan Elongation At A Temperature Difference Of 60°C = 7 M X 12 X 10⁻⁶ X 60°C ≒5 Mm).

Step 3: Small Caps And Snow Stoppers (Day 6)

• Insert A Rear End Into The Goby End And Hold It In Two Points With Rivets Φ3.2 X 8 Mm.
• In Areas With Snowy Areas, The Second Level From The Top Is Used To Hold The Eterna Snow Stopper And Auxiliary Screws.Allowable Sliding Load 1 Kn/Pc.

Step 4: Building Wrapping And Final Finishing (Day 7)

• Kasagi Nobori 45 X 30 Body Edges Are Installed Continuously On The Core.
• Blind Rivets Are 200 Mm Each With Ridge Wrapping Sheet Metal (Working 300 Mm) Covering Each Of 50 Mm On The Left And Right.
• Total Sealing Implantation: Modified Silicon, With A Thickness Of 4 Mm Or More And U-Shaped.
• After Completion, A Watering Test Was Conducted For 15 Minutes From The Eaves To Confirm That There Was No Leakage.

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Engineering Checklist (Self-Inspection After Construction)

item	Specified Values	Measurement Method	Passing Criteria
Roof Slope	Over 1/30	Laser Leveling Or Leveling	≧2°
Number Of Screws	≧22 Pieces/Sheet	Visually	0 Missing
Goby-Cancellation Rate	100%	Vibration And Light Hit Test	No Misalignment Or Play
Roofing Layer	≧150 Mm	Visually	No Protrusion
Sheet Metal End Clearance	5 Mm±2	Deposit	Within Thermal Expansion Tolerance
Gutter Mounting Slope	1/300	Water Thread	No Reverse Slope

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Budget Simulation (7 M X 5 M Gable, Equivalent To 70 M2 Of Total Floor)

Expenses	Unit Price	Quantity	Subtotal
Rigid Panel 0.4 Mm	¥1,650/M	35 M	¥57,750
A Set Of Roles	–	–	¥38,000
Roofing	¥6,500/Volume	Two	¥13,000
Bis Rivet	–	–	¥8,000
Scaffolding (7Th)	¥700/M2	150 M2	¥105,000
Tool Rental	Impact Etc.	Set Of	¥12,000
Total	–	–	Approximately 230,000 Yen

*Specialist Competitor Estimates (Kanto 2025 Average) Are 550,000 To 700,000 Yen Under The Same Conditions.You Can Save Approximately 50% By Self-Construction.

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Common Failures And Countermeasures

Symptoms	Cause	countermeasure
The Goby Floats	Field Distortion On The Structure Side	Add Intermediate Fixing With Gasket Screws
The Rain Sound Is Loud	Lack Of Insulation	Glass Wool 24K + 5Mm Sound Insulation Sheet Added To The Ceiling
Condensation Water Circulates Behind The Arabesque	Unprocessed Keraba And Arabesque Interlock	Waterproof Tape + Resealing
Surface Temperature In Summer 75℃	Low Reflective Color	Highly Reflective Coating (Sri50 Or Higher) Top Coat

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Legal And Insurance Points

• Japanese Wooden HousesHeight 13M, Eave Height 9M Or LessThere Is No Need To Apply For Confirmation (Excluding Expansions), But If You Want To Change The Structural Strength Or The Main Structural Parts In Terms Of Fire Prevention, A Confirmation Application Is Required.
• When Setting Up A Footing, It Is Highly Recommended To Take Out "Fall/Falling Disaster Insurance."The Compensation Is Around 1,200 Yen Per Day, And Is 10 Million Yen.
• Galvanized Steel Sheets Fall Under The Building Standards Act "Notice No. 1474 - Non-Combustible Materials" And Have Also Passed Roof Fire Regulations For Article 22 Areas.

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Summary

In One Week, A Roof With A Total Floor Of 70 M2 Is Ready To Go Like New - And It Costs Approximately 230,000 Yen, Including Materials Costs.Even Amateurs Can Fully Realize The Stair-Riding Roofing Process As Long As You Follow The Process.Even If You'Ve Never Gripped A Tool, There Are No Points To Be Confused If You Can Simply Delete The Four-Step Flow And Checklist In Order.Please Take The First Step.

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Reference Links And Videos

• Official Catalogue Of Nippon Steel Steel Sheet "Nisku Color Pro" (Paint Film Guarantee, Physical Properties)
• Building Materials Station Rakuten Store "Simple Line Type 2" (Actual Price)Rakuten Market

This Article Is Based On Product Specifications And Laws Published As Of April 2025.Please Be Sure To Check The Official Manufacturer And Local Government Documents For The Latest Information.