Insulation
PIR boards, mineral wool, cavity batts, EPS, and insulated plasterboard for achieving building regs U-values in walls, floors, and roofs of a domestic extension.
Cavity Wall Insulation Batts: Partial Fill, Full Fill, and the Mistake That Costs Thousands
UK guide to cavity wall insulation batts for extensions: DriTherm 32 vs 37, partial vs full fill, retaining clips, 0.18 U-value target, and the mortar dropping problem nobody warns you about.
EPS Insulation: The Budget Floor Board That Needs More Thickness but Saves You Hundreds
UK guide to EPS polystyrene insulation boards. EPS70 vs EPS100 grades, thickness for Part L compliance, correct floor build-up, cable contact ban, and prices from £6-12/m².
Insulated Plasterboard: The One-Board Fix for Cold Solid Walls
UK guide to insulated plasterboard (thermal laminate): PIR, phenolic, and EPS types compared, dot-and-dab vs battens, VCL sealing at sockets, and the thickness that actually meets Part L.
Mineral Wool Insulation 100mm: Glass Wool vs Stone Wool, Where Each Goes, and How to Install It Without Itching for a Week
UK guide to 100mm mineral wool insulation: glass wool vs stone wool differences, lambda values, loft and stud wall installation, acoustic air-gap principle, PPE, and current prices.
PIR Insulation Board 100mm: The Standard Thickness for Extension Floors and How to Get It Right
The UK homeowner's guide to 100mm PIR insulation: why it's the default for extension floors, how it meets Part L 2021, brand comparison with prices, and the installation details that determine whether your floor actually performs.
PIR Insulation Board 120mm: Flat Roofs, Upgraded Floors, and the Joist Depth Problem
The UK guide to 120mm PIR insulation: where it's specified, how it meets Part L 2021 for flat roofs and floors, the joist depth trap, and how to buy Celotex XR4120 at the right price.
PIR Insulation Board 50mm: Where It Works, Where It Doesn't, and How to Install It
The UK homeowner's guide to 50mm PIR insulation: which walls and roofs it suits, how to cut and fit it, brand comparison, and the joints mistake that wastes 30% of your insulation's performance.
PIR Insulation Board 75mm: The Combination Thickness That Fills the Gaps
75mm PIR insulation explained for UK homeowners: where it meets Part L on its own, where it needs layering, costs from £22-28/board online, and the combination builds that make 75mm the right choice.