structural
Loft boarding and loft ladders
Loft boarding turns an unused roof space into storage without touching the insulation underneath it, which is the whole point of doing it properly. Expect £30 to £60 per square metre for raised boarding, plus £250 to £450 for a ladder and hatch.
What it costs. Loft boarding costs £30 to £60 per square metre for a raised deck that keeps the insulation intact, plus £250 to £450 for a ladder and hatch. Full cost breakdown for loft boarding.
What the job covers
- Raised loft boarding over insulation
- Loft ladders and hatches
- Loft lighting and walkways
- Strengthening loft joists
- Boarded storage decks
What is involved
Modern insulation is deeper than the joists it sits between, usually 270mm against joists of 100mm. Boarding straight onto the joists crushes the insulation to a third of its depth, which costs you heat and can cause condensation in the roof space. Raised boarding solves it: a system of legs or a timber counter-batten lifts the deck clear, the insulation stays fluffed, and there is a ventilation gap above it.
A typical job is a deck of tongue-and-groove boards over raised supports, a walkway from the hatch, and a light. Most lofts also need the hatch enlarged, because a 562mm opening will not take anything you actually want to store. Weight matters: a domestic ceiling joist is sized to hold up plasterboard, not boxes, so a carpenter should tell you what the deck will carry and where the load-bearing runs are.
Choosing someone for the job
Ask what the boards sit on. If the answer is the joists, and the insulation is deeper than the joists, walk away. Ask about the hatch, because an unchanged hatch limits what a boarded loft is useful for. Ask whether they will leave a ventilation path at the eaves.
Common questions
Will boarding my loft cause damp?
It can, if the boards sit directly on the joists and squash the insulation. A raised deck with an air gap above the insulation and clear eaves ventilation avoids it.
How much weight can a boarded loft hold?
Ordinary ceiling joists are not designed for storage loading. As a rough guide treat a domestic boarded loft as light storage only, and get advice before storing anything heavy or concentrated.
Do I need building regulations approval?
Not for boarding out for storage. You do the moment it becomes a room, which brings in floor strength, escape routes, fire protection and head height.
Can I board a loft with trusses?
Partially. Trussed roofs have webs criss-crossing the space, so you get boarded bays rather than an open deck, and the webs must never be cut.