Spray Foam Insulation FAQs

Over ten years of spray foam expertise has given us a vast technical knowledge. Some of the most common questions are answered below.

What are the differences between closed-cell and open-cell foams?

There are three major differences. Firstly, BASF uses the versatility of chemistry to offer a closed-cell content of greater than 90 percent for all of its formulations, and open-cell foams commonly used as insulation systems have approximately 90 percent open-cell content. Secondly, closed cell content offers a thermal conductivity of between 0.028 W/mk and 0.025 W/mk, depending on the thickness applied. Open cell offers 0.039 W/mk. Thirdly, both closed cell and open cell foams are virtually impermeable to air, while open cell foam will allow far more vapour to pass through it.

We do not recommend open cell foams for treatment of condensation to any substrate that is impermeable. This includes, profiled steel roof and wall cladding and non-breathable roofing felts. The poor vapour resistivity of open cell foams can lead to interstitial condensation and subsequent waterlogging of the insulation.

How are polyurethane foams applied?

Our systems are spray-applied, two-component products that include a hardener (A-Side Component) and a resin (B-Side Component). These are not pre-formed, friction-fit batts or boardstock insulations. It is not a wet application – no water is used. During application, there is a chain reaction between the two components that creates a bond to the substrate as it reacts and expands. It dries, cures and hardens within 3-5 seconds. This product should always be installed by a trained applicator.

What equipment is required?

Spray-applied polyurethane foam systems require specific application equipment, including pumps, proportioners and spray guns. BASF are pleased to advise on the best equipment for processing their insulation systems.

Are there any special handling considerations?

Always use personal protective equipment, avoid all contact with skin and eyes and do not inhale the vapours of the hardener. Before opening the resin, unscrew the bung slowly to release the gas pressure in the drums.

While spraying, always work with adequate ventilation. Protective gloves and face masks are mandatory. When atmospheric levels may exceed the occupational exposure limit (PEL or TLV), approved air purifying respirators equipped with an organic vapour sorbent and particulate filter can be used as long as appropriate precautions and change-out schedules are in place. Persons with known respiratory allergies must avoid exposure to the A component.

What is the insulation U-value of your systems?

ECON Polyurethanes will calculate the u-value of any structure that uses WALLTITE® insulation foam. All we need is the thickness of each layer through the structure and your target U-value.

What are the differences between roofing foams and wall foams?

Polyurethane foams are plural-component products engineered on the molecular level for a specific purpose and application. Externally applied roofing foams tend to offer higher compressive strengths and smoother surfaces, while foams for timber framed walls and between rafter roof insulation, tend to offer faster reaction rates, higher yield and superior insulation values. Our polyurethane technologies include closed and open cell foams.

What is an insulating air barrier system?

A spray-applied polyurethane foam system that combines superior insulation values and near-zero air permeability in a single application to improve building durability, energy efficiency and occupant comfort, health and safety.

Does polyurethane technology control air leakage?

Our polyurethane foam roof and wall systems have been tested as an air barrier at an application of 50mm thickness. Once applied, our roof and wall systems are fully-adhered and do not allow air to flow around, behind or through the insulation system. Most open-cell foams have not been tested and therefore do not qualify as air barrier systems. Open-cell foam products require an application of up to 125mm to control air leakage.

Can an insulation system add structural strength?

Spray-applied closed-cell polyurethane foam is the only insulation material that adds structural integrity throughout the wall system. Testing shows spray-applied polyurethane foam insulation between wood- and steel-stud wall panels, increases rack and shear strength, two to three times compared with standard timber frame components with glass fibre insulation, when sprayed onto gypsum wallboard, and increases racking strength when sprayed onto oriented strandboard (OSB).

Closed cell foam injected into a cavity, has enough strength to bond two leaves of a masonry wall together, in situations where the existing wall ties have failed.

What about mould?

Mould requires three things to grow: moisture, warm temperatures and a food source. Polyurethane foam insulation has no nutritional value and is not considered a food source for mould. The use of polyurethane as insulation eliminates surface condensation and reduces the potential to accumulate moisture. It also eliminates air movement within the wall cavity. Other insulations are less successful at controlling air infiltration and providing adequate insulation to eliminate surface condensation, thus increasing the possibility of an environment susceptible to mould.

Is polyurethane good for the planet?

Our polyurethane technologies are formaldehyde-free formulas that emit no volatile organic compounds (VOCs) and use zero ozone depleting blowing agent technology. Plastic building products, including polyurethane foam, use less energy from all sources than alternative products during production. Spray-applied polyurethane foam insulation saved 3.4 trillion BTUs in manufacturing energy over glass fibre in 1990. Our systems also increase building energy efficiency and reduce waste.

Can polyurethane foam systems be used in a chemically sensitive environment?

Yes. Our systems do not emit Volatile Organic Compounds (VOCs). Off-gassing from the product has been measured at less than 1.25µg/m³, way below the CertiPUR standard limit.

Are there any fire protection requirements?

BASF’s WALLTITE closed cell polyurethane insulation meets Class 1 surface spread of flame rating when tested to BS 476: Part 7. Once installed, if 30 minute fire resistance is required, it must be covered by plasterboard, or similar thermal barrier. A class 0 fire rating can also be achieved by applying WALLTITE® FB 100 intumescent coating to the foam.

Is Enertite foam airtight?

Yes, both open cell and closed cell spray and injection polyurethane foam have been independently tested for airtightness and performed exceptionally well as an air barrier with figures as low as 0.028m³/hr.m² for open cell.

Is Enertite spray foam insulation breathable?

Yes, both open and closed cell foams are vapour permeable, allowing vapour diffusion through the system. Open cell is more vapour open than closed cell with a µ factor of 3.2. Unlike open cell foam, closed cell foam is impervious to water penetration. Liquid water has a much larger structure and is unable to pass into or through a closed cell foam barrier.

Can Enertite spray foam be applied to non-breathable roofing felt?

No. Spray foam should not be applied non-breathable roofing felt regardless of type in line with building regulations requirements and good building practice. Such membranes behave as vapour barriers. A vapour permeable slide should be used to maintain a 50mm ventilation void between the insulation layer and roof membrane.

Can spray foam be applied to breathable roofing felt?

In line with building regulations Enertite open cell foam can be applied directly to breathable roof membranes when a counter-batten has been installed between the roof tile or slate batten and roofing membrane. In certain circumstances closed cell foam may be applied directly to breathable roofing felts without the need for a counter batten. Please consult our technical department for information relating to your specific construction.