Insulation: What Homeowners Should Know in 2026

A concise guide to insulation types, where to insulate first, common problems, and what to watch out for with spray foam. ## Where to Insulate First Heat loss in a typical uninsulated UK home: - **Roof/loft** — 25% of heat loss. Loft insulation is the single most cost-effective energy upgrade. - **Walls** — 35% of heat loss.

Cavity wall insulation is straightforward; solid wall insulation is more complex and expensive. - **Floors** — 10% of heat loss. Often overlooked but worthwhile during renovation. - **Windows/doors** — 20% of heat loss. Addressed by glazing upgrades. ## Common Insulation Types | Type | Best For | Typical Cost | |---|---|---| | Mineral wool (loft roll) | Loft spaces | £5–10/m² | | Blown fibre | Hard-to-access loft areas | £10–15/m² | | Cavity wall beads/foam | Standard cavity walls | £6–12/m² | | External wall insulation | Solid-wall properties | £80–120/m² | | Internal wall insulation | Where external is not possible | £40–70/m² | | Spray foam (open-cell) | Property-specific roof design | Quote required | | Spray foam (closed-cell) | Property-specific roof design | Quote required | ## The Spray Foam Question Foam can restrict timber inspection and conceal roof defects.

Suitability and moisture risk depend on the complete roof build-up, product, thickness, climate, underlay and air and vapour control layer. Neither open-cell nor closed-cell is inherently safe or unsafe, and open-cell is not automatically lower risk. Government modelling assesses defined scenarios, not every existing roof.

Ask a lender for its exact written requirements. Not all foam needs removing and removal does not guarantee lending. There is no reliable one-size removal price; sufficient accurate information can support a firm remote quote, distinguished from an estimate. [EvoHome Improvements' own in-house team carries out removal](/services/spray-foam-removal), with an [independent professional final survey included on every removal](/services/spray-foam-removal/independent-survey).

Repairs and reinstatement are specified in the agreed quote; changes are agreed in advance. [Start a conversation](/quote?service=spray-foam-insulation-help) without photos or a report. Sources: [RICS consumer guidance](https://www.rics.org/consumer-guides/spray-foam-insulation) and [government moisture-risk modelling](https://www.

gov.uk/government/publications/moisture-risk-of-spray-foam-insulation-applied-to-timber-sloped-roofs). ## What to Ask an Installer - What U-value will the insulation achieve? - Will ventilation be maintained or improved? - Is a condensation risk assessment included? - What guarantee is offered and by whom? - Will Building Regulations notification be handled?

--- ### What to do next If you are weighing up an insulation upgrade, EvoHome Improvements can help you understand the right option for the property, plan the project sensibly and, where appropriate, connect it with suitable independent installers or specialists. These insulation projects are…