Which UK lenders allow spray foam insulation in 2026?
A short and conditional list — most accept only open-cell foam with full documentation.
Acceptance is rare. Leeds Building Society, Newbury Building Society and a small number of specialist lenders are the most commonly cited as willing to consider open-cell installations. Conditions almost always include a current independent inspection, BBA certification of the product, and confirmation that ventilation is preserved.
Closed-cell foam is rarely accepted by any UK lender in 2026. Even where considered, expect higher rates and lower loan-to-value caps.
Frequently asked questions
Will more lenders accept spray foam in time?＋
Unclear — pressure for clarity is growing but the direction so far has been tightening.