If your home was built after the 1920s, there's a good chance it has cavity walls — a small gap between the inner and outer brick layers. Left unfilled, that gap allows a significant amount of heat to escape through your external walls. Cavity wall insulation fills that gap, turning a weak point in your home's thermal performance into one of its strengths.
Princeton Eco Plus provides professional cavity wall insulation and extraction services to homeowners across the West Midlands, Worcestershire, and Staffordshire, helping households reduce heat loss, improve comfort, and lower their energy bills.
Cavity walls are built with a gap — usually between 50mm and 100mm — between the outer and inner brick or block layers. This gap was originally designed to prevent moisture from passing through to the inside of the home, but it also allows heat to escape relatively easily, since air is a poor insulator on its own.
Cavity wall insulation involves injecting an insulating material — commonly mineral wool fibre, polystyrene beads, or foam — into that gap through small holes drilled in the external wall. The material fills the cavity, significantly reducing the rate at which heat passes through the wall, while the holes are neatly filled and colour-matched afterwards so there's no visible sign of the work once complete.
An unfilled gap offers little resistance — warm air moves straight through the wall and outside.
Insulation material fills the gap, significantly slowing how quickly heat can pass through the wall.
Walls are typically the single largest source of heat loss in an uninsulated home — filling the cavity makes a substantial difference.
Walls are the single largest source of heat loss in an uninsulated home, so filling the cavity makes a substantial difference.
With less heat escaping, your heating system doesn't need to run as long or as hard.
Insulated walls reduce cold spots and draughts, particularly noticeable in rooms with external walls on multiple sides.
Most homes are completed in a matter of hours, with no need for scaffolding or major building work.
Unlike internal wall insulation, cavity fill doesn't reduce room size, since the material goes into the existing gap.
Cavity wall insulation is one of the most recognised measures for improving a property's Energy Performance Certificate score.
Works well alongside loft insulation, boiler upgrades, and renewable technologies as part of a whole-home efficiency plan.
If older or degraded insulation is causing damp or performance issues, we also offer cavity wall extraction and replacement.
Submit your property details through our online form.
We assess whether your property's wall type and age make it suitable for cavity fill.
A qualified surveyor inspects your walls, checks the cavity condition, and identifies the right specification for your home.
Small holes (typically 22mm) are drilled at intervals across the external walls, insulation is injected, and holes are neatly filled and colour-matched.
We inspect the completed work to confirm full, even coverage before signing off the job.
We'll confirm an exact, fixed price once your survey is complete — no hidden extras.
Get your quote →Our surveyors and installers are experienced in assessing cavity wall suitability correctly — an important step, since not every property is a good candidate for cavity fill, and getting this wrong can cause damp problems down the line. Every installation is backed by our commitment to using accredited materials and correct fitting standards. Flexible finance options are available for households who would prefer to spread the cost over time.
Most homes built with a cavity wall structure after the 1920s are suitable, but exposure to wind and rain, wall condition, and cavity width all need checking first — which is exactly what our free survey covers.
No — installation is done entirely from the outside, takes just a few hours for most homes, and the drilled holes are filled and colour-matched so they're barely noticeable afterwards.
When installed correctly in a suitable property, cavity wall insulation does not cause damp. Problems typically only arise when insulation is fitted in unsuitable properties without the right assessment — which is why our survey stage is so thorough.
Cavity wall insulation is designed to last the lifetime of the building, with no ongoing maintenance required.
Many households notice improved comfort — fewer cold spots and draughts — almost immediately, with the full impact on energy bills becoming clear over the following heating season.
We offer cavity wall extraction services to remove old, settled, or damaged insulation before installing fresh material, restoring full thermal performance.
Request your free survey — or call 03301 130 943 to speak to our team.
Request your free survey
