Expanding Foam

About Expanding Foam

Expanding foam, also known as polyurethane foam or PU foam, is an essential product for professional tradespeople and DIY enthusiasts tackling insulation, filling, and sealing projects. This versatile material is dispensed from a pressurised canister and rapidly expands to fill gaps, cavities, and voids before curing into a rigid, insulating foam. MyToolShed.co.uk stocks a comprehensive range including hand-held aerosol foams for quick applications and professional gun-grade foams for precision work requiring controlled dispensing.

The expanding foam range at MyToolShed features trusted brands including Everbuild, Fischer, Polycell, Ronseal, Draper, and Sealey, offering solutions for everything from general gap filling to specialised thermal insulation. Products are available in different expansion rates and formulations, alongside essential accessories including applicator guns, replacement nozzles, and specialist foam cleaners to maintain equipment and ensure professional results.

Applications

Expanding foam is used across numerous trades and applications:

• Window and Door Fitters: Sealing frames, providing insulation, and ensuring draught-proof installations
• Builders and General Contractors: Gap filling, cavity insulation, and securing pipework or conduits
• Plumbers and Heating Engineers: Sealing pipe penetrations, sound-deadening, and securing boiler flues
• Electricians: Filling holes after cable runs and fire-stopping around electrical installations
• Roofers: Sealing roof penetrations, filling gaps in soffits and fascias, and improving loft insulation
• Plasterers and Dry-Liners: Fixing plasterboard to uneven walls and filling voids before finishing
• Shopfitters and Carpenters: Securing architraves, fixing skirting boards, and general void filling
• DIY Enthusiasts: Home insulation projects, draught-proofing, and general property repairs

Choosing The Right Expanding Foam

Application Type: Determine whether you need hand-held aerosol foam for occasional jobs or gun-grade foam for professional, frequent use. Gun-grade systems offer better value for regular users and allow partial use with minimal wastage.

Expansion Rate: Low-expansion foams are essential around window and door frames where excessive pressure could distort frames, whilst high-expansion products efficiently fill large cavities and gaps in masonry or timber.

Specialised Formulations: Consider whether you require standard general-purpose foam or a specialist product. Fire-rated foams are essential for fire door installations, whilst thermal foams offer enhanced insulation properties for energy efficiency projects.

Accessories Required: Gun-grade foam requires a compatible applicator gun. Budget for foam cleaner to maintain your gun between uses, as uncured foam will permanently damage equipment if left to harden. MyToolShed.co.uk stocks complete systems including guns, nozzles, and cleaning solutions.

Safety Information

Always wear protective gloves when handling expanding foam, as uncured foam adheres strongly to skin and is difficult to remove. Safety glasses are recommended, particularly when working overhead. Ensure adequate ventilation in confined spaces. Tradespeople should be aware that expanding foam products contain isocyanates subject to COSHH regulations. Use only fire-rated foams where required by Building Regulations, particularly around fire doors and service penetrations. Store canisters upright in cool, dry conditions away from heat sources, and never puncture or incinerate pressurised containers.

Frequently Asked Questions

How long does expanding foam take to dry?

Most expanding foams become tack-free and trimmable within 30-60 minutes, though this varies by product and ambient conditions. Full curing typically takes 12-24 hours. Warm, humid conditions accelerate curing, whilst cold, dry environments slow the process.

What's the difference between gun-grade and hand-held expanding foam?

Gun-grade foam requires a separate applicator gun, offering precise control, the ability to stop and restart application, and minimal wastage. Hand-held foam comes with a disposable straw applicator and must typically be used entirely once started. Gun-grade systems are more economical for professional or frequent users.

Can I use expanding foam outside?

Yes, but cured foam will degrade when exposed to direct UV light, causing discolouration and brittleness. For external applications, always over-paint, render, or otherwise protect cured foam from sunlight to ensure longevity.