Timloc Through-Wall Cavity Sleeve for One Airbrick 229×76 (1 pcs)

The Timloc through-wall cavity sleeve is the straightforward solution to a problem that catches out a surprising number of builds and renovation jobs. When you fit an airbrick through a cavity wall, the cavity itself sits between the inner and outer leaf with nothing to stop debris, mortar droppings, or general muck from blocking the airflow path. This sleeve bridges that gap, lining the cavity between the two skins so air passes cleanly through without becoming a slow-motion rubble tip. Sized to suit a standard single airbrick at 229x76mm, it drops into place during construction or can be retrofitted with a bit of patience.

Made from a tough, flexible plastic, the sleeve compresses slightly if needed, which is handy when cavity widths are not exactly textbook. That flexibility also means it seats neatly rather than cracking under pressure from surrounding masonry. It is worth noting that flexible does not mean flimsy here. These sleeves are built to sit inside an external wall indefinitely, so material quality matters more than it might first appear.

Where the Timloc Through-Wall Cavity Sleeve Gets Used

The most common application is suspended timber floor ventilation, where building regulations require airbricks at regular intervals to keep the underfloor void dry and free from condensation. Get the cavity sleeve wrong or skip it entirely and you create a blockage point that defeats the whole purpose of the airbrick. They are also used in wall ventilation generally, including areas where gas appliances need permanent air supply, and anywhere a clear through-wall air path is required.

On new builds, these go in during the blockwork or brickwork stage as the cavity is built up. On extensions, the same applies. On older properties being upgraded or having airbricks replaced, they can usually be slid into position through the existing opening with a bit of care. Not glamorous work, but the kind of detail that matters when a building inspector is checking ventilation provision or when a damp surveyor is trying to work out why a ground floor is holding moisture.

Getting the Size Right

This sleeve is designed for a single standard airbrick opening at 229x76mm. Timloc also produce sleeves in other sizes for double and triple airbrick configurations, so if your opening is larger, check the full range before ordering. The cavity width of your wall determines whether any trimming or adjustment is needed on site, though most standard cavity widths are accommodated without modification.