New-build vs older home: insulation compared
When your home was built largely determines what it needs. Here's the quick guide by era.
A home's age is the best predictor of its insulation needs. Here's a rough guide by era — though a survey always beats assumptions.
Pre-1920s (solid wall)
Usually solid walls (no cavity), often draughty, frequently with thin loft insulation. Loft insulation and draught-proofing are the easy wins; wall insulation is a bigger project.
1920s–1990s (cavity wall)
Most have cavity walls — often unfilled in older examples. Cavity wall and loft insulation together are high-value, low-disruption upgrades.
Modern / new-build
Generally built to better standards with insulation included — but not always to the latest depth. Often just a loft top-up is needed, if anything.
The takeaway
Older homes have the most to gain. If yours is pre-1990 and hasn't been upgraded, a survey will usually find worthwhile, cost-effective improvements.
How to find out what you've got
Not sure which era your home fits? A few clues help: solid walls are usually one-and-a-half bricks thick with a distinctive brick pattern (headers and stretchers), while cavity walls show a more uniform stretcher pattern. Loft insulation depth is easy to check yourself with a tape measure. When in doubt, a free survey settles it quickly.
Where to focus by era
- Pre-1920: loft + draught-proofing first; solid-wall insulation later.
- 1920–1990: loft + cavity wall together for the biggest win.
- Modern: usually just a loft top-up, if anything.