Weatherboard Calculator
Enter board type, dimensions, and overlap - effective cover is calculated automatically
Full face width of the board
0 for shiplap, T&G, and square edge
Standard: 3.6 m, 4.2 m, 4.8 m, 6.0 m
- enter width and overlap
Fixings per board = wall width - stud spacing
1 per stud for featheredge; 2 for T&G face-fixed
10% for straightforward runs; 15% for complex shapes, many cuts, or diagonal boarding
Wall Sections
Job Costing (optional)
~10 m² per litre for end-grain primer
UK Market PricesFills in the material cost fields with current UK market prices. You can review and edit each price before applying.
Results
Net Cladding Area
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m² (less openings)
Boards to Order
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inc. waste
Linear Metres
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boards ordered
Fixings
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nails / screws
Wall Breakdown
| Wall | Gross Area | Openings | Net Area | Boards | Fixings |
|---|
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Frequently Asked Questions
How much weatherboard cladding do I need per square metre?
Coverage depends on the board width and fixing gauge (exposed face). A 150 mm board at 125 mm gauge = 8 linear metres per m² of wall. Add 10% waste for end cuts and openings. Choose board lengths (3.6 m, 4.2 m, 4.8 m) to minimise joins on your longest wall runs.
What is the difference between weatherboard and featheredge cladding?
Weatherboard: general term for horizontal overlapping timber or fibre cement cladding. Featheredge: tapered solid timber board, thicker at one edge - traditional UK profile. Shiplap: rebated edges that interlock without overlap. Fibre cement (e.g. HardiePlank): timber look with greater durability, no rot risk, lower maintenance.
Do I need a breather membrane behind weatherboard cladding?
Yes - a breather membrane (VPM) should be installed behind all external cladding. It allows water vapour to escape from inside while blocking wind-driven rain from reaching the wall structure. It also acts as a secondary weatherproofing line if water penetrates the boards. Required under Approved Document C.
How do I fix weatherboard to a timber frame wall?
Fix to 25 x 38 mm or 38 x 50 mm battens creating a ventilated cavity. Use stainless steel ring-shank nails or screws to prevent corrosion staining. Start at the bottom with a starter strip. Overlap each board by minimum 25-30 mm. Fix with a single nail/screw per batten to allow seasonal movement.
What maintenance does timber weatherboard cladding need?
Stained or oiled timber: inspect and retreat every 3-5 years. Painted timber: repaint every 5-8 years. Retreat before cracks appear - once moisture gets in, rot follows. Replace any boards showing rot promptly. Factory pre-treated boards offer better initial protection than site-treated ones.
What waste allowance should I use for weatherboard cladding?
Simple rectangular wall, few openings: 10%. Walls with many windows, doors, or corners: 15%. Use the longest available board lengths to minimise end joints. Buy all boards from the same batch to ensure consistent colour and treatment.