Loft boarding
Raised loft boarding in London
Storage space that does not cost you your insulation. We board on battens or loft legs so the full depth of wool survives underneath, and you get a flat, safe deck on top.
- Raised on battens or loft legs — never laid flat on insulation
- Tongue-and-groove moisture-resistant loft panels
- Screwed, not nailed, so panels can be lifted later
- Eaves left clear so the roof keeps ventilating
- Fitted alongside insulation in a single visit
The problem raised boarding solves
Most people want two things from a loft: for it to keep the heat in, and for it to hold their belongings. Left to themselves, those two requirements fight. Insulation works by depth. Storage works by having something flat to stand on. And a standard ceiling joist is around 100mm deep, while the recommended insulation depth is 270mm.
Screw boards directly to the joists and the physics is unforgiving: you compress 270mm into 100mm, and compressed mineral wool loses most of its thermal value because the still air it relies on has been squeezed out. Homeowners do this constantly, in good faith, and it quietly cancels a large part of the insulation they just bought.
Raised boarding fixes it. Battens or purpose-made loft legs lift the deck clear, the insulation stays at full uncompressed depth underneath, and you get a proper floor above. It costs more than laying boards flat. It is also the only version that leaves you with both things you wanted.
Battens or loft legs?
Both work; which we use depends on the roof. Timber battens fixed to the joists give a very solid deck and suit lofts with regular, sound joists and reasonable headroom. Proprietary loft legs are quicker, lighter and clip directly to the joist, which suits trussed roofs and situations where we want to keep the added load as low as possible. We decide on survey and the choice is on your quote.
How much should you board?
Less than you think. The instinct is to board everything, but a full-footprint deck is expensive, adds weight across the whole ceiling, and tends to encourage insulation being pushed into the eaves to make room for it — which is exactly what you do not want.
Our usual recommendation is a generous central area reached directly from the hatch, squared off and edged, with the eaves left open. You get the storage you will actually use, the roof keeps ventilating properly at the perimeter, and the cost falls. If you genuinely need the full area, we will board it, but we will explain the trade-off first.
What a proper boarding job includes
- Load assessment. We look at joist depth, span and spacing and tell you what the deck is sensibly good for. Ceiling joists are not floor joists.
- Full-depth insulation preserved. The whole point. Nothing gets compressed.
- Access retained. Panels screwed rather than nailed and left liftable over cabling, junction boxes, pipework and the tank.
- A safe edge. The deck is squared and, where it matters, edged so nothing rolls off into the eaves.
- Ventilation protected. The perimeter airflow path stays open.
Boarding is not a loft conversion
It is worth being blunt about this, because it is the most common misunderstanding we meet. A boarded loft is storage. A habitable room requires structural floor joists, a compliant staircase, fire separation, escape provision and building control sign-off. Boarding gives you none of those and does not pretend to. If a room is what you want, you need a conversion specialist — and we will insulate it properly once it exists.
Doing it in one visit
If your loft needs insulating and boarding, do them together. It is cheaper, because the battening and the insulation are planned as one build-up rather than one being retro-fitted around the other. It is faster, because everything happens in a single day. And it removes the risk of a separate boarding contractor arriving later and flattening the insulation you have already paid for, which we are called out to correct more often than we would like.
See loft insulation installation for the insulation side, or the full loft makeover if you want lighting and a ladder in the same visit.
In the loft
Boarding in practice
Storage that works without quietly undoing the insulation underneath.
Questions & answers
Loft boarding — common questions
Can I board straight over my insulation?
Not without ruining it. A 270mm layer squashed under boards screwed to 100mm joists performs roughly like 100mm of insulation — you have paid for depth and then removed it. Raised boarding on battens or loft legs is the only version worth having.
How much weight will it take?
Domestic ceiling joists are designed to hold up a ceiling, not to be a floor. Raised boarding is suitable for normal domestic storage — boxes, suitcases, seasonal items — and we will tell you honestly if your joists are shallow enough that we would want you to keep the load light. It is not a substitute for the structural work a habitable room requires.
What board do you use?
Tongue-and-groove moisture-resistant loft panels, cut to fit and screwed rather than nailed so they can be lifted later if a cable or pipe needs reaching. We leave access to anything that will foreseeably need it.
How much of the loft should I board?
Usually less than people first ask for. Boarding the full footprint costs more and buries the insulation performance question across the whole ceiling. A generous central deck reached from the hatch, leaving the eaves unboarded and ventilating freely, is both cheaper and better for the roof.
Can you board around the water tank?
Yes, and we usually build a small raised platform beside it so it stays accessible. What we will not do is board over it or insulate beneath it.
Can boarding be added later?
It can, but it is cheaper to do it at the same time as the insulation, and it avoids the risk of a boarding contractor flattening a job you have already paid for. If you think you might want storage eventually, mention it at survey stage even if you are not buying it now.
What homeowners say
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Written and fact-checked by the Loft Insulation London survey team, who assess loft spaces across the capital every working week. Last reviewed .
Want the storage and the warmth?
Book a free survey and we will design the insulation and the deck together, as one job.