Advice
Can you board a loft in a new build?
Yes, you can board a new build loft for light storage. The boards need to sit on a raised frame above the insulation, with the vents at the eaves kept clear. NHBC does not say boarding cancels its warranty, but its cover does not include alterations or any damage they cause.
Why can't you use the loft in a new build house?
You can. The warning comes from one line in an NHBC leaflet for homeowners, and it is about airflow, not a ban.
"The roof space isn't intended to be a storage area. If you do put items up there, you could restrict the air flow and the items may get damaged by condensation."
NHBC, condensation in your roof space.
The worry is the vents. Many pitched roofs have a ventilation slot along the eaves, and the same leaflet says: "Therefore, it's important that you don't block these ventilation slots or restrict the airflow."
New build lofts also tend to have deep insulation, often higher than the joists. That is a reason to raise the boards, not a reason never to board. More in can you board over loft insulation.
Source: NHBC, condensation in your roof space. Read 21 October 2026.
Does boarding a loft affect an NHBC warranty?
Nothing NHBC publishes says boarding voids the warranty. What it does say is that alterations, and any damage they cause, are not covered. So the job has to cause no damage: boards raised clear of the insulation, vents left open and no cuts to the trusses.
NHBC's answer to homeowners reads: "Your Buildmark policy doesn't provide cover for any alterations or extensions to your home, or for any damage or problems caused by the work."
If your home has a different warranty provider, check your own policy document.
Source: NHBC, Buildmark policy questions. Read 21 October 2026.How deep is the insulation in a new build loft?
Usually deeper than the joists, so boards need legs tall enough to clear it.
In homes built from 2012, the typical loft reading is 300mm, across 2,709 homes with a depth on their most recent certificate. More than half of those lofts measured (55.4%) have 300mm or more. Homes built 1996 to 2002 typically read 200mm, across 12,216 homes.
One caution. Only about 1 in 16 homes built from 2012 (6.1%) have a recorded depth, so those 2,709 are not a random sample of new builds.
The building regulations set a heat loss target for new homes, not a depth. Approved Document L sets that target as a figure for heat loss through the roof, with no depth. The Energy Saving Trust adds: "If you're using mineral wool, make sure you don't squash it: this will reduce its effectiveness as an insulator." That is why we fit boards on raised legs.
Sources: our own count from government energy certificate data, explained on how we work out our figures, read October 2026; Approved Document L, Volume 1, Table 1.1 (roofs U = 0.11 W/(m²·K)); Energy Saving Trust, roof and loft insulation. Both read 10 October 2026.Not sure what is in your new build loft?
The survey is free and takes about twenty minutes. You get a written price before any work starts.
Are new build roof trusses strong enough for storage?
For light storage, usually. But no published figure tells you what your own roof can hold. That sits in the builder's truss design.
The current NHBC standard covers new homes begun from 1 January 2026. It says trussed rafters "should not be cut, modified or repaired" except to the designer's instructions. The Trussed Rafter Association says: "Trussed rafters must never be cut or trimmed, unless specified by a trussed rafter designer."
A raised floor sits on top of the trusses and cuts nothing. The free survey checks the joists. More in is my loft strong enough to board.
Sources: NHBC Standards 2026, clause 7.2.4; Trussed Rafter Association, the buyers' guide to trussed rafters. Both read October 2026.What is the safest way to board a new build loft?
Six things to get right.
Fit the boards on legs tall enough to clear the insulation. The Energy Saving Trust warns that squashing mineral wool "will reduce its effectiveness as an insulator".
Leave a ventilated gap under the boards. LABC Front Door says the gap is there "to prevent condensation on the underside of the boards". More in will loft boarding cause condensation.
Keep the eaves clear. NHBC asks you not to block the ventilation slots.
Newer lofts may have ventilation ducts in the insulation. The NHBC standard allows "installing the ductwork between the layers of horizontal insulation". Boards must not crush them.
Ask the builder for the truss design and your handover pack.
The Planning Portal says laying boards over the joists "may require a building control application". See loft boarding regulations.
Short answers
Can I put things in my new build loft?
Yes, light things on a raised boarded floor. NHBC's leaflet warns that loose items can "restrict the air flow and the items may get damaged by condensation", so keep them on the boards and away from the eaves.
How much weight can a new build loft take?
Only the truss design for your house can say. Ask the builder for it and keep to light things like cases and decorations. We explain where the figures you see online come from in is my loft strong enough to board.
Can you board a council house loft?
Ask your landlord first, because councils set their own rules for tenants. As one example, North Tyneside Council says of its own homes: "Boarding out lofts will only be allowed following a fixtures and fittings application providing the work is for light storage only, such as the storage of suitcases and Christmas decorations."
Does boarding the garage roof affect the warranty?
NHBC publishes nothing specific to garages. The same NHBC wording applies: alterations, and damage caused by them, are not covered.
Can I take out the insulation to board on the joists?
Not a good idea in a new build. The home was built to a heat loss target in Approved Document L, and NHBC does not cover damage caused by alterations. Raise the boards instead.
More advice
Get your new build loft checked
New build lofts can be boarded well. We board lofts on raised legs, and top up the insulation where it falls short. Book the free survey and we will check the joists and give you a written price. Most lofts take one to two days. Not sure it is worth doing? Read is it worth boarding a loft.
Complete Loft Services sorts out loft boarding and insulation across Cambridgeshire and the surrounding counties. The survey is free, and you get a written price before any work starts.
Written by Ben Criddle, who runs Complete Loft Services. Published . Facts checked on .