Understanding PAS 2035: the gold standard for Welsh retrofit

PAS 2035 is the UK's recognised standard for retrofitting domestic buildings. It mandates that every retrofit project begins with a proper assessment by a Retrofit Coordinator, who designs a package of measures that work together rather than conflicting.

For Welsh homes — many of which are solid-walled, stone-built or pre-1919 — this matters enormously. Slapping insulation into a building without understanding moisture risk can cause more harm than good. PAS 2035 forces installers to consider ventilation, airtightness and the whole building as a system.

At Insulation Installers Wales, every job we take on is planned against PAS 2035 principles. Our assessors look at your property's construction, its current condition, and how different measures interact before recommending any work. It's slower than a quick quote, but it's the difference between insulation that performs and insulation that causes problems.