How to Board a Loft: Step-by-Step DIY Guide (2025)
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Boarding your loft is one of the best home improvement projects you can do. It's relatively straightforward, takes just a day or two, and the result is a clean, accessible storage space that can transform how you use your home.
This guide takes you through the entire process from start to finish — including the one thing most guides get wrong: how to board your loft without compressing your insulation.
What You'll Need
| Item | Purpose |
|---|---|
| Loft stilts | Raises boards above insulation level |
| OSB loft boards | The boarding surface |
| 4.0 x 30mm screws | Fixing boards to stilts |
| Cordless drill/screwdriver | Driving screws |
| Tape measure | Measuring joist spacing and board positions |
| Pencil | Marking cut lines |
| Hand saw or jigsaw | Cutting boards to size |
| Knee pads | Comfort while working |
| Dust mask and gloves | Safety |
| Loft light | Illuminating your work area |
Before You Start: The Insulation Problem
This is the most important thing to understand before you begin. Most UK homes have — or should have — 270mm of loft insulation. If you lay boards directly on your joists, you will compress this insulation, reducing its effectiveness and increasing your energy bills.
The solution is raised loft boarding. Loft stilts clip onto your joists and raise the boarding platform to 175mm above joist level, preserving the full depth of your insulation beneath. This is the correct way to board a loft, and it's what we recommend for all projects.
Step 1: Plan Your Layout
Before you start installing anything, spend 15 minutes planning your layout. Measure the area you want to board and sketch it out on paper. Consider:
- Where the loft hatch is — you'll want easy access from the hatch to the main storage area
- Any obstacles such as water tanks, pipes, or roof timbers
- The direction of your joists — stilts clip onto the joists, so you need to know which way they run
- How many stilts and boards you'll need (use our guide at FAQs or email us)
Step 2: Check Your Joists
Before adding any load to your loft, check that your joists are in good condition. Look for signs of rot, woodworm, or damage. If any joists look suspect, consult a structural engineer before proceeding.
Also check the spacing between joists. Standard UK joist spacing is 400mm or 600mm centre-to-centre. Our loft stilts are designed to work with both spacings.
Step 3: Install the Loft Stilts
Loft stilts are designed to be simple to install. Here's how:
- Position the stilt over the joist so the joist fits into the channel at the base of the stilt
- Press down firmly until the stilt clips onto the joist — you should hear a click
- Repeat along the length of the joist, spacing stilts approximately 600mm apart
- Work your way across the loft, installing stilts on each joist in your boarding area
No screws or fixings are needed to attach the stilts to the joists — they clip on securely and can be removed if needed.
Step 4: Lay the Boards
With the stilts in place, you can start laying the boards. OSB loft boards are 1220 x 300mm — a size specifically designed to fit through standard UK loft hatches.
- Start from one corner of your boarding area and work outwards
- Place each board on top of the stilts, ensuring it spans at least two stilts
- Fix each board to the stilts using 4.0 x 30mm screws — use 2 screws per stilt contact point
- Where boards need to be cut to fit around obstacles, use a hand saw or jigsaw
- Boards can be butted up tightly against each other for a seamless surface
Step 5: Finish and Tidy Up
Once all the boards are laid and fixed, do a final check:
- Walk across the boards to check they feel solid and don't flex or creak
- Check that all screws are fully driven and no heads are proud of the surface
- Sweep up any sawdust or debris
- Consider adding a loft ladder if you don't already have one — it makes access much easier
How Many Stilts and Boards Do I Need?
As a rough guide:
| Loft Area | Stilts Required | Boards Required |
|---|---|---|
| ~4 m² | Box of 32 | Pack of 12 |
| ~7 m² | Box of 64 | Pack of 18 x 2 |
| ~11 m² | Box of 96 | Pack of 18 x 3 |
| ~15 m² | Box of 128 | Pack of 18 x 4 |
Not sure? Email us at info@thediyer.co.uk with your loft dimensions and we'll calculate exactly what you need.