The short answer
It depends on the scope. Removing foam on its own is not normally a re-covering, but reinsulating may be treated as renovating the roof's thermal layer under Part L, and a re-roof above the Planning Portal limits needs approval. Those limits are 25 per cent of the building envelope and 50 per cent of the roof. Check with your building control body before work starts. We walk you through consent, and any notification that applies is ours to submit.
Two jobs, two sets of questions
Spray foam removal usually bundles two pieces of work. The first is stripping the foam from the rafters, which is largely a cleaning and recovery task. The second is whatever goes in afterwards: new insulation, new underlay, repaired timbers, and perhaps a re-covered slope. The regulations follow the second far more than the first.
That is why a one-line answer seldom fits. Clearing foam from a small section behind a chimney is a different proposition from stripping a whole roof and insulating all of it again. The survey sets out what is actually proposed, and the building control question flows from that. Where the position is unclear, we suggest asking before work begins and not after it has been done and covered up.
The Planning Portal limits for re-covering
A building control application is normally unnecessary, says the Planning Portal, for repair or re-covering work that touches less than 25 per cent of the total building envelope and less than 50 per cent of the roof. Here the envelope counts every external element at once: the walls, the floor, the roof, the windows, the doors and any roof windows or rooflights.
Approval is needed if you pass those limits, make structural alterations, fit a covering whose fire performance differs from the old one, or use a covering that makes the roof 15 per cent heavier or more. Passing the limits can also bring wider considerations, such as making sure the thermal insulation is sufficient. These tests concern re-covering. When foam removal comes with new underlay and tiles over a large slope, they are the first measure we apply to the proposal.
How Part L treats new insulation
Approved Document L, volume 1, deals with energy performance in homes. Roofs count as thermal elements in the document, and stripping a layer back to the rafters then rebuilding it is listed as renovation. Should renovation reach beyond half of the element's surface, or amount to a major renovation (more than a quarter of the external envelope), the whole roof must reach a U-value of 0.16 W/(m²·K).
For a roof element that is new or replaced in an existing home the same document sets 0.15 W/(m²·K), and it allows a lesser standard where that would cost headroom. Its note says the insulation and any air gap together should match the rafter depth at the least. How those paragraphs bear on a given foam removal is for building control to judge, so we put the proposal to the council or an approver before the work starts and record what they say.
Who you ask, and what we do
Swindon Borough Council operates its own building control team, and domestic work can go through a full plans application or a building notice. Private firms offer another route as registered building control approvers, the term used since April 2024. Elsewhere in our area the route differs: Wiltshire Council's building control team, the Southvale service for the Vale of White Horse, Cotswold District's own team and Building Control Solutions for West Berkshire.
You do not need to untangle this alone. Consent is something we talk through with you, and when the work is notifiable, the Building Regulations notification goes in from us, along with a briefing on what the inspector expects. Where listed status or a conservation area is involved, planning is a separate matter, and our page on spray foam in listed buildings covers that side.
Ventilation and condensation when you reinsulate
Whatever replaces the foam must suit the way the roof is built. A cold roof, with insulation along the loft floor and ventilated rafters above, relies on air moving at the eaves. Marley's summary of BS 5250 gives eaves ventilation allowances that change with pitch and underlay type, and adds high-level ventilation for steeper roofs and long spans. A warm roof, with the insulation laid in and above the rafters, is detailed quite differently.
Getting this wrong recreates the moisture problem the foam caused, which is why our page on spray foam and condensation bears on the choice of material. If the house feels cooler once the foam is out, why a house can feel colder after removal covers the usual reasons and the cure.
Garages, sales and paperwork
Outbuildings follow the same logic in miniature. A foamed garage roof can fall under different expectations from a house because of its use, but that depends on the structure, so ask before assuming. Our page on spray foam in a garage roof covers it.
Paperwork counts when you sell. A completion certificate for new insulation, or a note that building control was consulted, helps a buyer's solicitor and lender. RICS tells owners to confirm with their lender that foam is acceptable, and our spray foam and mortgages guide covers the lender positions reported in November 2024. The mess of the job itself is dealt with in how messy spray foam removal is.
What you receive from us
The route is straightforward. A surveyor goes into your loft, takes photographs and measures up, and a single-figure written quote comes after. If building control is involved, the quote names who inspects and when. When the job finishes we clear away and remove the waste, and you are given a 10-year workmanship guarantee, in writing.
For the full picture of what removal involves, see our spray foam insulation removal page. To start, ring 01793 626096, message via WhatsApp or the enquiry form, mentioning whether the roof is being re-covered or only reinsulated.