Foam Insulation Frequently Asked Questions


Do you have questions about what we do or how we do it? The products we use? How we will operate on the day of install? We have tried to answer as many questions as we can below. If there is anything more that you would like to know that has not been answered within this frequently asked questions page then feel free to contact us by phone or email and will be happy to answer any other questions.

Why do I need spray foam insulation?

There are a number of benefits to installing spray foam insulation in your home. The primary benefits are that it can; improve EPC rating, save on energy costs, reduce airborne noise pollution, improve air quality and moisture management and reduce cold air crossing to the inside living space. All of these come together to improve living or working conditions.

For a more detailed breakdown of the benefits of spray foam insulation visit this page.

How long will the process take to complete? Can I use the property while the process is taking place?

The process can take 1-2 days depending on the complexity and size of the job. If we quote for your spray foam insulation project we will give you an estimate of how long it will take based on the area that needs to be covered.

The property can be used while the process is underway, there will be traces of chemical fumes due to the products being used. However we endeavor to ventilate the work area as best as possible and keep the process as non intrusive as it can be. You do not need to leave the property while we work.

How much will it cost to install spray foam insulation?

We can’t give a fixed price per square meter, the final cost will depend on numerous factors such as; the total area, depth you want the foam sprayed, foam type, access and location of the site.

If you have had a quote from another company we can also quote by email without visiting your property. We simply need to know the area to be sprayed, desired foam type and depth, the available access and a few other pertinent details. All this information will be readily available on any quote supplied previously.

Should you not have an existing quote to hand we simply need the measurements from your loft and if this isn’t possible we can estimate the area from the size of your property which can be measure from the outside. We would be pleased to provide more guidance on this by phone or email.

In either case we will require photos of the site and surrounding area, these can be sent to us by phone or email.

Please make contact with us by phone or email for more information.

Does the foam insulation pose a fire hazard?

The foam insulation is graded to class 1 fire rating when tested to BS 476 Part 7.

Once the foam insulation is installed can alterations be made to the roof/structure?

Yes alterations can be made. Open cell products are very easily modified and removed, it is a lighter consistency than closed cell. Closed cell can often be used as a bonding agent and can be more difficult to alter and remove but it is still possible. You should always ask for help when attempting to alter or remove foam insulation if you are unsure.

The process that we use does not involve bonding directly to the roof tiles as many installers have done in the past, we will always install a layer between the tiles and the foam so as roof repairs and alterations can be undertaken as normal.

I am concerned about moisture being trapped and causing damp, mould or rot in my timbers. Will this happen and how can it be avoided?

No, both open and closed cell foam insulation products provided by FoamInstall are breathable. In roof spaces we also will install a layer between the foam and the tiles to allow for air exchange under the tiles.

The foam insulation (open or closed cell) and the timbers in the roof have similar ‘breathability’ properties. Foam is also inert providing no nutritional value and so is not a viable food source to promote mould growth.

We would only ever recommend spraying in closed cell spray foam insulation in to a loft space against the tiles. This is because it is extremely water resistant yet breathable. Like leather shoes or Gortex® fabric. Water vapor can diffuse through the closed cell foam insulation material liquid water cannot.

Is spray foam insulation ‘water proof’?

Open cell spray foam insulation is not, in fact it can act a bit like a sponge which is why we do not recommend it for use in loft spaces or anywhere else where the insulation may come in to contact with water.

Closed cell spray foam insulation however is hydrophobic so it is the best and in our opinion only viable option if installing foam insulation in an area where it may come in to contact with water and get wet. For example in lofts under slate or tiled roofs, basements floors, basement walls, floors, external walls or buildings of metal construction such as commercial and industrial buildings.

How does the application process work? 

Foam insulation is projected from our high tech foam applicators releasing a combination of two substances that blend together at the nozzle and immediately begin an exothermic reaction, settling on the surface and expanding after a few seconds to create the foamy substance. The foam fills the space and creates an air-tight seal, it then hardens over a period of 2-5 minutes and after 1 hour the substance will have cured and have a hardened outer layer.

What is the foam insulation made of? Is it environmentally safe?

The foam insulation is made up of two components that are mixed together to create an exothermic reaction. These components can differ between suppliers of the compounds. Generally the compounds consist of a bonding agent and a resin.

Yes the compounds are environmentally safe. The products are tested and rated by suppliers and show an extremely low Global Warming Potential and no Ozone Depletion Potential.

What is the difference between open and closed cell foam insulation?

Both spray foam insulation types provide excellent insulation and a near air seal but open cell is a lighter foam, with an R-Value of 3-3.5 per inch. Closed cell is a denser foam, with an R-value of 6-7 per inch.

Because closed cell foam is the more efficient insulator it does not need to be sprayed on as thick to achieve the same insulation properties as open cell spray foam. In fact half the thickness of closed cell foam insulation is required to achieve the same insulation properties as open cell. And conversely open cell spray foam insulation is a more efficient insulator that traditional fiberglass insulation.

Closed cell spray foam insulation is as discussed water resistant, even under pressure, yet it is breathable and so it is the only spray foam that should be used where contact with water is likely. 

Open cell spray foam insulation is more suited to being used between a dry wall construction or floors. This is because doesn’t work as a vapor barrier nor does it resist the ingress of water.


For a FREE no obligation quote or more information
Call us now on: 0800 020 9132