Hand-held expanding foam comes with a disposable straw nozzle attached to the can. It is quick to use and suited to occasional or one-off jobs. Gun-grade foam requires a separate foam gun, but gives far greater control over how much foam is dispensed. This reduces waste, makes it easier to fill gaps accurately, and allows the same can to be reused across multiple sessions as long as the gun is cleaned after each use. For regular or larger-scale work, gun-grade foam is the better choice.
Expanding Foam for Gap Filling, Sealing and Insulation
MacBlair stocks a focused range of polyurethane expanding foams from Evo-Stik, covering the most common applications on site and at home. Available in 500ml and 750ml sizes, the range includes both hand-held cans with straw nozzles and gun-grade canisters for use with a foam gun. Gun-grade foam gives noticeably better control over application rate, which matters when filling gaps around door frames, window settings, or pipe penetrations through walls.
For jobs where fire resistance is a requirement, MacBlair carries the Evo FP404 fire retardant expanding foam in both hand-held and gun-grade formats. This one-component PU foam is tested to EN 1366-4 and provides up to 120 minutes standalone fire resistance in joints, making it the right choice for compartmentalising walls and floors in shared or commercial buildings. If you need to pair it with a compatible sealant, the sealants range at MacBlair includes options worth considering alongside fire-rated foam work.
Common uses across the range include:
- Sealing gaps around window and door frames
- Filling small wall penetrations for pipes, cables, and ducts
- Fire-resistant sealing of connection joints in partition walls
- Acoustic and thermal insulation in construction joints
Evo-Stik foam guns are stocked alongside the canisters, giving everything needed to get started in one order. Once cured, the foam can be cut, sanded, and painted. For jobs that also call for bonding or mounting, the grab adhesives and insulation fixings stocked at MacBlair are worth checking alongside this range. Order online with delivery across Northern Ireland, or collect from a local branch.
Expansion Joint FAQ's
Cure times vary depending on the product, gap size, and humidity. Most PU expanding foams reach a tack-free surface in around 10 to 15 minutes. Full cure, where the foam can be cut, sanded, or painted, typically takes between 1 and 2 hours. Larger fills or very dry conditions can extend this. Lightly misting the surface with water before application speeds up curing, as PU foam reacts with moisture to expand and set.
Yes, expanding foam is widely used to seal the gap between window and door frames and surrounding masonry. For this application, a low-expansion or controlled-expansion foam is preferable, as standard high-expansion foam can exert enough pressure to bow a frame. Gun-grade foam gives better control over the amount applied. Fill the gap in stages rather than all at once, and allow each application to expand before adding more. Once set, trim flush and finish with a suitable sealant if the joint will be exposed.
In many domestic situations, standard PU foam is acceptable for filling gaps around pipes and frames. However, where a wall or floor forms a fire compartment boundary, such as in flats, commercial buildings, or where building regulations specify fire resistance, a fire-rated foam must be used. Fire retardant expanding foam, such as the Evo FP404, is tested to EN 1366-4 and can provide up to 120 minutes standalone fire resistance in a sealed joint. Always check current building regulations for your specific situation if in doubt.
Uncured foam can be wiped away with acetone or a dedicated foam cleaner while still wet. Once it has cured, it cannot be dissolved and must be cut or scraped back mechanically. For skin contact, do not try to scrub uncured foam off as this drives it deeper into the skin. Leave it to cure and it will peel away more cleanly. Wearing disposable gloves, eye protection, and working in a ventilated area will prevent most accidental contact. Foam that has cured onto clothing is generally not removable.