Polystyrene bead cavity insulation is removed by opening the outer leaf at intervals and drawing the beads out with industrial vacuum extraction. Loose beads flow out fairly readily, while bonded beads, which were injected with an adhesive, have set into a mass and need to be broken up with rods and compressed air first. The job also includes sealing gaps where beads have been escaping and a final borescope check.
What is polystyrene bead cavity insulation?
Expanded polystyrene, or EPS, beads are small white or grey balls blown into the cavity through holes drilled in the mortar. There are two main types:
- Loose beadsBlown in without any binder. They flow like dry sand and will run out of any gap they can find.
- Bonded beadsCoated with an adhesive as they are injected, so they stick together and set into a lightweight, porous mass that stays in place.
Beads do not absorb much water themselves and are often chosen for more exposed walls, but that does not mean they never cause problems. Water can still track through gaps between beads, around ties and over rubble, and a poorly filled wall can be left with voids. Beads in the wrong place, such as under the floor or in the loft, are a separate nuisance, and dealing with them is a regular part of our Liverpool cavity insulation extraction work.
Signs you may need bead insulation removed
- Beads spilling out of air bricks, weep holes, old drill holes, gaps around windows or service entries.
- Beads under the floor or in the loft, which can block underfloor ventilation and get into wiring and pipe runs.
- Damp after the install on the exposed side of the house, especially around openings.
- Planned building work such as a new door, window or extension, where cutting the wall would release loose beads.
- Wall tie or structural repairs that need a clear cavity.
- Uneven fill found on inspection, with voids that leave cold spots.
A burst of beads when you replace a window or remove an air brick is very common with loose fill. It is a sign the cavity is not sealed, not necessarily that the whole wall has to be cleared. We will tell you which applies after a cavity wall inspection.
How we remove polystyrene beads from a cavity
- Identify the type. A borescope survey confirms whether the beads are loose or bonded, how full the cavity is and whether there is debris or damp.
- Contain the spill points. Vents, air bricks and gaps that beads are escaping from are covered so material does not end up across the garden or under the floor during the work.
- Open the wall. Bricks are removed at intervals. Loose beads often need fewer openings because they flow towards the extraction point; bonded beads need closer spacing.
- Extract. Industrial vacuum equipment draws beads into sealed bags. For bonded beads, rods and compressed air break up the set mass first, working section by section.
- Clear stragglers. Beads clinging to ties and mortar are worked loose, and the base of the cavity is cleared of beads and rubble.
- Re-check. We look into the cavity again with the borescope from several points.
- Rebuild and seal. Bricks go back, pointing is matched, and openings that were leaking beads, such as unsealed air bricks, are dealt with.
The underlying process follows our standard cavity wall extraction method, with the extra containment that beads need.
Beads are light and static-prone, and they travel. Pulling out an air brick or cutting into the wall yourself can release a lot of material quickly. Please leave the wall alone until it can be done with proper extraction equipment.
Bead insulation in Liverpool and Merseyside homes
Bead fill was widely used on homes thought to be more exposed, which here includes many coastal and edge-of-town properties. We come across it on post-war semis and 1970s to 1990s estates in Maghull, Heswall and St Helens, as well as across the Wirral peninsula. Even where beads were the right choice of material, south-westerly rain off the Irish Sea still finds weak pointing, missing trays and rubble bridges. So if bead-filled walls are damp, we look at the whole wall rather than assume the beads are at fault.
What affects the cost?
Bonded beads usually take more time than loose beads because the set mass has to be broken up. Other factors include the wall area, access and scaffolding, how many vents or openings need sealing, any beads to clear from under floors or lofts, and the amount of rebuilding and pointing. Our cost guide covers these factors and published figures.
When to call a professional
Call us if beads are pouring from vents or holes, if you are planning building work on a bead-filled wall, or if damp has appeared since the beads went in. If the fill in your home is foam rather than beads, see our foam cavity insulation removal page instead. We handle polystyrene bead and other cavity insulation removal across Merseyside and will explain the options clearly before quoting.
Beads escaping or damp walls?
Call 07777 659786 and tell us where the beads are coming out or where the damp is, and when the insulation went in. We will call back and arrange a borescope inspection to confirm the type of bead and its condition.
Frequently asked questions
Can polystyrene bead insulation be removed from a cavity wall?
Yes. Loose beads are vacuumed out through openings made by removing bricks at intervals. Bonded beads take longer because the adhesive has set them into a mass that must be broken up with rods and compressed air first. In both cases the cavity is checked with a borescope before the wall is closed up.
Why are polystyrene beads coming out of my air bricks?
Loose beads flow freely and will escape through any gap into the cavity, such as unsealed air bricks, weep holes, old drill holes or gaps around frames. It usually means the cavity was not properly sealed at those points when it was filled. Sealing the gaps may be enough, but we will check for any wider problem.
What is the difference between loose and bonded beads?
Loose beads are blown in dry and stay free-flowing. Bonded beads are coated with adhesive as they go in, so they stick together and stay put if the wall is cut. Bonded beads are less likely to spill but harder to extract. A borescope inspection shows which you have.
Do polystyrene beads cause damp?
Beads absorb little water themselves, but damp can still occur if water tracks through gaps, over rubble or around ties, or if the outer wall is in poor condition. If you have damp in a bead-filled wall, it is worth checking pointing, trays and rainwater goods as well as the fill.
Can beads be cleared from under my floor too?
Beads that have escaped under suspended timber floors or into lofts can usually be vacuumed out where there is safe access. Clearing them helps keep underfloor ventilation working. We look at this during the visit and include it in the written quote if needed.