Raised loft boarding uses loft legs to lift storage boards above your insulation. Find out how it works, why it matters and what should be checked before any boards go down.
Raised loft boarding is the go-to method for creating storage space in a loft that already has a good depth of insulation. Rather than squashing the insulation, the boards sit on supports above it. It sounds simple, and in many lofts it is, but a few checks beforehand make the difference between a solid, lasting floor and one that causes problems down the line.
What is raised loft boarding?
Raised boarding uses purpose-made supports, usually called loft legs, loft stilts or loft risers, which are screwed to the tops of the ceiling joists. Boards are then fixed to the top of these supports, creating a storage deck that sits above the insulation rather than on it. Most systems are made from rigid plastic, and some can be cut or stacked to suit different insulation depths.
The aim is to keep the insulation at full depth underneath, while leaving a small air gap between the top of the insulation and the underside of the boards.
Why it matters
- It protects your insulation. Loft insulation works by trapping air. Compress it and it performs less well. The Energy Saving Trust guidance on roof and loft insulation notes that raising the floor slightly allows you to add insulation across the joists before fitting boards.
- It helps with condensation. That same guidance advises leaving a small gap for ventilation between insulation and boards to help prevent condensation.
- It gives a flatter floor. Joists aren't always perfectly level. Supports can help even out small differences.
For the bigger picture on keeping insulation working, see our guide to boarding over loft insulation without squashing it.
What to check before fitting
Joist condition and spacing
Every support is only as good as the timber it's fixed to. Joists should be checked for rot, woodworm, splits, sagging or old notches cut by previous trades. Spacing matters too, as boards need support at sensible intervals so they don't flex between joists.
Roof structure and load
Raised boarding is for storage, and the ceiling joists below it were usually designed mainly to hold up the ceiling and resist the roof spreading, not to carry heavy loads. Trussed rafter roofs in particular have slim timbers that should never be cut, notched or altered. Spread weight sensibly, keep heavy items close to supporting walls and avoid boarding more than you need. If you're unsure what your roof can take, a structural engineer can advise.
Ventilation
A cold loft needs air moving through it, typically from vents at the eaves. Insulation and boards must not block those openings. If the loft already shows signs of condensation, such as damp patches, mould on timbers or water droplets on the underside of the roof, the cause should be found before boarding.
Electrical cables
Cables running across the joists can get trapped beneath supports or boards, or buried deep in insulation where they can't release heat as designed. It may be necessary for an electrician to reroute or clip cables so they're clear and accessible. Never screw down a board without checking what's underneath.
Downlights
Recessed downlights in the ceiling below can produce heat that rises into the loft. Depending on the fitting, insulation or boards may need to be kept clear, or a suitable cover used. Check the light fittings and manufacturer's guidance, and ask an electrician if you're unsure.
Headroom and access
Raising the floor reduces headroom, so check you'll still have a comfortable space to kneel or crouch. Good access matters too: a safe fitted loft ladder and a decent-sized hatch make boarding far more practical.
Raised boarding vs boards on joists
| Feature | Raised boarding | Boards fixed to joists |
|---|---|---|
| Insulation depth | Can stay at full depth | Limited to joist depth unless compressed |
| Ventilation gap | Built in above insulation | Often none |
| Headroom | Slightly reduced | Maximum |
| Best suited to | Lofts with deep insulation | Lofts with little or no insulation over the joists |
Common mistakes to avoid
- Cutting insulation back: trimming or removing insulation so supports sit flat undoes much of the benefit of raising the boards.
- Boarding right to the eaves: pushing boards and insulation hard into the edges can block the airflow a cold loft relies on.
- Covering the water tank area: leaving a boarded walkway to the tank is useful, but insulation shouldn't be laid underneath the tank itself.
- Forgetting future access: consider fitting a removable board over junction boxes or anything that may need checking later, so you don't have to lift the whole floor.
Does raised boarding need Building Regulations approval?
Boarding for storage is not the same as creating a habitable room, and simple storage boarding is not normally treated as a conversion. However, circumstances vary, especially if structural changes are involved. If in doubt, check with your local Building Control. Our article on loft storage vs loft conversion explains where the line usually falls.
Thinking about raised boarding?
We fit raised boarding in homes around Stourbridge and the wider West Midlands. Have a look at our loft boarding service, or call 07506 746177 for a chat about your loft.
Frequently asked questions
What are loft legs?
Loft legs, also called loft stilts or risers, are supports screwed to the top of ceiling joists. They raise storage boards above the insulation so it can stay at full depth, with a small air gap underneath the boards to help reduce the risk of condensation.
Can raised loft boarding be fitted in a trussed rafter roof?
Often, yes, as long as the trusses are left completely intact and the area is used for light storage. Trussed rafters should never be cut or notched. If you're unsure what the roof can safely carry, ask a structural engineer or the truss manufacturer.
Will raised boarding reduce my headroom?
Yes, slightly, because the floor sits higher than the joists. How much depends on your insulation depth and the supports used. It's worth checking you'll still have enough room to move around comfortably before deciding how high to raise the boards.
