What is the best insulation for a new extension

Kingspan

Hi.Would be great if you could tell where you want to add it.

100mm Kingspan insulation board on ground floor, above water barrier and below floor screed. Ps look at installing underfloor heating at this time (shop around for your best quote) 100-150mm insulated plasterboard on basement walls. (Inside of water barrier, batten out wall to allow for electrical conduit and water pipes then fix plasterboard onto studs/battons) 50mm plasterboard on all Ceilings If the above ground level has a cavity then your brick layers can fit 50mm poly board insulation as they build or blown in Insulation after walls are up. Also 150 poly board between rafters is a definite! (Make sure to vent or have an airflow gap that is vented. Regards Andrew Smyth

Firstly a basement conversion . Should have high density polystyrene boards or rigid mineral wool boards.. The above ground extension should have 75mm PIR boards in the cavity walls . Then a warm deck roof to achieve the highest UValue