Thermofoam Thermal Acoustic Insulating Foam – Everbuild

Thermofoam Thermal Acoustic Insulating Foam from Everbuild is a gun-applied polyurethane foam made for the gaps that let heat and noise through. Window frames, door frames, pipe and cable penetrations: anywhere a gap needs filling and sealing rather than just stuffing with something and hoping for the best.

What sets it apart from a general-purpose can of foam is the flexibility. Buildings move. Timber shrinks, plastic frames expand in the sun and contract overnight, masonry settles. A rigid foam can crack away from the substrate as that happens, and once it does you’ve lost the seal. Thermofoam is formulated to absorb that movement, so the bond between frame and wall stays intact. That is what keeps the airtight barrier working years after the install.

Thermofoam Insulating Foam Performance

The numbers back it up. Acoustic insulation is rated up to 64 dB to EN ISO 717-1, and air permeability is certified at a<0.1 m³ to EN 12114. Fire classification is Class E to ISO 13501, which is standard for a PU foam of this type. Temperature resistance runs from -40°C to 80°C, with short-term exposure up to 100°C. In plain terms, it copes with a cold loft in January and a south-facing window reveal in July.

It adheres to the usual building materials: concrete, brickwork, wood, plaster, plastic, stone and metal. That covers most of what a window fitter or general builder meets in a day, so you are not swapping products between jobs.

Where It Gets Used

Window installation is the main one, including clean, controlled back-filling around the frame and sealing of roller blind cavities. It also suits gap filling around external door frames, though this must always be used alongside mechanical fixings. The foam seals and insulates, it does not hold the door up. It is also well suited to filling cavities where services pass through walls, such as pipes, cables and ducting.

Getting a Good Result

Preparation matters more than people think. Surfaces need to be clean, sound and free from dust and loose particles, then lightly moistened with water just before application. The moisture helps the foam cure properly. In deeper cavities, build up in layers and dampen between each pass. Underfilling is better than overfilling here, because the foam expands by around 30% after it leaves the nozzle. Overfill and you will be trimming cured foam with a knife and muttering about it.

Always use the can upside down, shake it well before attaching it to the gun, and squeeze the trigger gently to control the flow. If you leave the gun attached between jobs that is fine, but when you remove it for storage, purge it thoroughly with Everbuild Foam Cleaner. Dried foam in a gun is a very expensive paperweight.