Best Draught Proofing & Weatherstripping — PU Expanding Foam + Budget (2026)
2 draught proofing & weatherstripping matching material “PU Expanding Foam” + price “Budget”, hand-picked from UK Amazon listings.
Not sure which one to pick? Read our Best Draught Proofing & Weatherstripping UK (2026) guide.
This budget-friendly PU expanding foam is a versatile solution for sealing gaps and cracks around your home to prevent draughts and improve insulation. Formulated with high-density polyurethane, it creates a robust, airtight seal ideal for tackling minor weatherproofing issues. The foam expands rapidly when dispensed, filling voids quickly and efficiently – perfect for DIY projects where precise fitting is key.
Designed for cost-effective sealing, this budget range PU expanding foam offers excellent thermal performance, helping to reduce heat loss in winter and keep your home cooler in summer. It's suitable for a wide variety of applications including window frames, door gaps, skirting boards, and even small cracks in walls. Remember to follow the manufacturer’s instructions carefully for optimal results and safe application.
This product is primarily intended for sealing gaps around windows and doors where draughts are noticeable. While effective for these common areas, it may not be suitable for large-scale insulation projects. Always assess the specific need before applying and consider professional advice if you're unsure about its suitability or proper usage.
#1 Pick
Soudal Genius Gun Gap Filler 500ml Expanding Foam- PU Expanding Foam
£8.55
Pros
- Patented Genius Gun applicator allows precise, single-handed application
- High thermal and acoustic insulation seals draughts around frames and pipework
- Well-established trade brand with a strong review track record
Cons
- Expanding foam needs trimming back once cured for a neat finish
#2 Pick
2 x 500ML Gap Expanding Foam Filler PU Expansion Insulation BONDING Filling- PU Expanding Foam
£10.98
Pros
- Twin-can pack covers more draught points than a single 500ml can
- PU foam bonds and insulates in one step around door and window frames
- Useful for roofing eaves, pipe entries and general gap sealing
Cons
- Needs a gun or straw applicator for controlled bead placement
FAQ
What surfaces can this PU foam be applied to?+
This expanding foam works effectively on a variety of materials including wood, metal, plastic, and plasterboard. However, it’s crucial to test a small area first to ensure adhesion and compatibility with the specific surface.
How much does one cartridge typically cover?+
The coverage varies depending on the size and shape of the gap being filled, but generally, one cartridge (approximately 750ml) can fill around 15-20 standard gaps effectively. Larger gaps will require more foam.
How long does it take for the foam to fully cure?+
The foam typically reaches full hardness within 24 hours at room temperature (18-24°C). However, allowing 72 hours for complete curing ensures maximum adhesion and a durable seal.
Should I use a tack cloth before applying the foam?+
Yes, using a tack cloth to remove dust and debris from the surface will ensure optimal foam adhesion. A clean surface is crucial for a strong and lasting seal.
Can I cut the nozzle of the cartridge for easier application?+
While possible, it's recommended to avoid cutting the nozzle significantly as this can affect the foam’s expansion properties. If you do adjust it, maintain the original size for best results.
Is this foam suitable for exterior use?+
This PU expanding foam is formulated for interior applications and might not be ideal for prolonged exposure to direct sunlight or extreme weather conditions. For exterior use, consider a specifically designed external sealant.
What tools do I need to apply this foam?+
You’ll need a suitable applicator – a caulk gun is highly recommended – along with gloves and safety glasses to protect yourself during application.
How do I clean up excess foam after applying it?+
Use a plastic scraper or putty knife to remove any excess foam. Clean the tool immediately with warm water and mild detergent. Do not use solvents or harsh chemicals.
What is the shelf life of this product?+
This PU expanding foam has a shelf life of approximately 12-18 months when stored in a cool, dry place away from direct sunlight. Check the ‘best before’ date on the packaging for accurate information.
Does this foam shrink after curing?+
Minimal shrinkage is expected after full curing. However, allow sufficient time (72 hours) for complete drying to minimise any potential movement or settling of the seal.