Construction Foam & Sponge.

Construction foam is used across the building sector to improve comfort, reduce energy costs and protect structural elements. Depending on the application, foam can help with thermal insulation, reduce noise, cushion against impact, and act as a barrier against air or water ingress. It also fills gaps between structural elements or building materials, helping to improve airtightness and prevent drafts or thermal bridging.

Closed-cell varieties in particular are well suited to construction due to their moisture resistance and durability, making them ideal for window seals, expansion joints, cladding, roofing and HVAC systems.

Not all foams are waterproof, but many closed-cell types used in construction are water-resistant. EPDM sponge, polyethylene foam and PVC foam are good examples. With a dense structure, closed-cell foam limits water absorption, making it reliable for environments where exposure to moisture or humidity is common. Selecting the correct foam grade ensures reliable, long-term performance.

At AS Rubber, we offer a range of foam materials with water-resistant properties suitable for the construction sector. Speak to our team to discuss the most suitable option for your application.

There are several types of foam commonly used in construction, each offering slightly different benefits:

• EPDM Sponge – often used in seals and gaskets thanks to its resistance to UV and weathering.
• Polyethylene Foam – lightweight and tough, great for thermal insulation and cushioning.
• Polyurethane Foam – performs well for both sound and thermal insulation.
• PVC Foam – ideal for sealing and insulating applications.
• Closed-Cell Sponges & Solid Rubber – well-suited to sealing and load-bearing uses.

Each foam is chosen based on where and how it will be used.

EPDM sponge is a popular choice because it stands up well to sunlight, rain, temperature changes and ozone. Its durability makes it suitable for long-term use in demanding environments.

It’s commonly used in glazing systems, HVAC units, and external cladding, where both flexibility and reliable insulation are required. Its closed-cell structure prevents water from soaking in, which is particularly useful in outdoor or exposed environments. You’ll often see it used in glazing systems, HVAC units, and external cladding. It’s also flexible, durable and helps with both thermal and sound insulation.

For general building insulation, closed-cell polyethylene foam is a reliable option. It helps to keep heat in and moisture out, making it suitable for both residential and commercial builds.

Polyurethane foam is also widely used, especially when acoustic insulation is needed. The most suitable foam depends on a range of factors, such as whether the goal is to reduce heat loss, manage sound levels, limit moisture, or achieve a combination of these.

Foam sheets have a few advantages compared to traditional insulation materials like mineral wool or fibreglass. They usually provide higher thermal performance per inch of thickness, which can be useful in tighter spaces, such as cavity walls, pipe boxing or confined service voids. Closed-cell foams also resist moisture and are easy to handle and shape on-site. The best choice depends on your project goals, budget and space limitations.

Foam sheet thickness depends on the area of use and the level of insulation required. Key factors influencing thickness include the building type, the desired U-value, local regulations, and the installation method. For walls, thicknesses between 25mm and 100mm are typical. Roofs and floors might need something thicker—up to 150mm in some cases—to meet energy efficiency targets.