Loft Stilts Sizing Guide: How Many Do I Need for My Loft?
Planning a raised loft boarding project requires calculating exactly how many Loft Stilts and OSB boards you need. Buying too few will halt your project midway, while buying too many wastes money.
This comprehensive sizing guide explains the spacing rules, the calculations, and provides quick-reference tables for common loft sizes to ensure you get exactly the right amount of materials for your space.
The Golden Rule of Spacing
Loft Stilts must be installed directly onto your existing ceiling joists. To provide a safe, structurally sound platform that won't sag, the stilts must be spaced correctly to support the edges and the center of your loft boards.
- Standard UK Joist Spacing: Most modern UK homes have ceiling joists spaced at either 400mm or 600mm apart (measured from the center of one joist to the center of the next).
- Board Size: Standard loft boards (OSB3 or chipboard) are typically 1220mm x 320mm (or 300mm).
Because the boards must join on top of a stilt for support, the number of stilts you need depends heavily on your joist spacing.
Quick Reference: Stilt Density
As a general rule of thumb, you can estimate the number of stilts required based on the square meterage of the area you wish to board:
| Joist Spacing | Stilts Required Per Square Metre (m²) |
|---|---|
| 400mm (Standard) | Approx. 8 to 9 stilts per m² |
| 600mm (Wider) | Approx. 6 to 7 stilts per m² |
Pack Size Guide by Storage Area
To make ordering simple, we sell Loft Stilts in pre-calculated pack sizes. Here is what each pack covers based on standard 400mm joist spacing:
| Pack Size | Coverage Area (400mm joists) | Best For |
|---|---|---|
| Box of 64 Stilts | Up to 7.24 m² | Small lofts, above-hatch storage patches |
| Box of 96 Stilts (Most Popular) | Up to 11.3 m² | Medium lofts, standard 3-bed semi-detached |
| Pack of 128 Stilts | Up to 14.28 m² | Large lofts, extensive storage needs |
| Pack of 256 Stilts | Up to 28.56 m² | Full-footprint boarding, large detached homes |
| Trade Pallet (480 Stilts) | Up to 55.0 m² | Trade professionals, multiple installations |
Don't Forget the Screws!
Each Loft Stilt requires 4 screws (two to secure the stilt to the ceiling joist, and two to secure the OSB board to the top of the stilt). Therefore, you need 4 times as many screws as you have stilts.
- For 64 stilts = 256 screws
- For 96 stilts = 384 screws
- For 128 stilts = 512 screws
We recommend our purpose-made 4.0 x 30mm wood screws, which are the perfect length to bite securely without piercing too deep into the joists.
Use Our Free Calculator
If you know the exact dimensions of the area you want to board, take the guesswork out of it entirely. Use our free Loft Stilts Coverage Calculator to get an instant, exact material list.