Heat Insulation

Insulation effects after treatment of a roof with polyurethane foam

Apart from being the best solution against roof leaks, polyurethane foam has another great property after it is sprayed under or on top of a roof: insulation against the heat from the blazing sun. The foam will at the same time keep the heat out and the cool air inside your rooms.

Closed cell spray foam insulation like ours, will expand to 3-5 times its dispensed volume, offers an R-value of 6.88 per inch of foam while filling all the gaps and cracks that can form in any structure. It eliminates drafts and increases comfort by producing an air and moisture barrier, thus reducing cooling costs. It also helps block mold, mildew and other airborne irritants and acts as a significant damper on noise pollution from outside the home. Fiberglass insulation can trap dry air, but if that air moves or becomes wet, the thermal resistance will drop significantly. That’s not the case with spray foam, which will adhere to nearly any surface with typically just one application.

Especially in Thailand, where the outside temperature during the hot season can easily reach 40 degrees Celsius, insulating your roof with spray foam is almost a necessity instead of a luxury. The aluminum foil that is often used by local builders and is placed directly under the roof tiles, has nearly no effect whatsoever and neither does the other types of thin metallic sheets that are currently on the market.


By spraying a layer of sprayfoam directly onto the roof tiles with a thickness of 5 cm (or 2 inches), amazing insulating results can be obtained that help protect your home significantly against excessive heat as well as excessive noise. The foam layer also forms a defensive barrier against insects or rodents like mice and rats as well.

Thermal Insulation

The effect on treatment of your roof with our spray foam against excessive heat has been measured many times by us, in order to determine the cost savings on the electricity bill for a single house.

On average, the temperature directly under the roof, in the roof attic, drops with 20 to 25 degrees Celsius right after treatment with spray foam. The temperature inside the rooms of your house will be reduced by an average of 3 to 5 degrees, depending on type of your window-and door frames, single or double glass panes, the thickness of your walls and the height of the ceilings in the rooms.

It makes no difference whether you have an angled roof or a flat roof; we can treat them both with the same results, a cooler living area. Concrete decks, steel decks and plywood decks like on certain type of condominium buildings can be treated by us all the same too.

Obviously, if your roof will be treated before air-conditioning has been installed, a smaller than usual air-con unit in each room will do and you’ll save costs on the principle purchase of a lighter than originally planned air-conditioning unit as well as on your energy bill.

Example of cost savings calculation

Imagine that you prefer a temperature of 24 degrees Celsius in your bedroom which today is not insulated. And let us assume that before you turn on your air conditioner, your room usually has a temperature of 30 degrees. Accordingly, your air-con unit has to bring the existing temperature of 30 degrees down by 6 degrees to 24 degrees, in order to reach the level that you feel comfortable with.

However, after the roof of your house has been treated with our sprayfoam, the temperature inside will have dropped by 10 % on average and is now only 27 degrees Celsius before you turn on the aircon. This means that the aircon unit has to cool down the temperature in that particular room from 27 degrees down to 24 only, so down 3 degrees instead of down 6 degrees. It’s not hard to figure out that this saves a lot on electricity use and depending on the size of the house, the cost of investment in roof treatment with spray foam is usually returned within 7-10 years, thanks to considerably lower energy bills.

Acoustic Insulation

Another great property of polyurethane foam, next to being the ultimate protection against leaking roofs and tropical heat, is the ability to protect against exterior noises. This, because a layer of sprayfoam reduces the transmission of sound waves. So, if you are being bothered by, for instance, noises of heavy traffic on a nearby highway or by the thumbing sounds of a pub or disco close to your home or simply by noisy neighbors, we have the solution for you.

Insulating a roof from the outside


In some cases we cannot spray the foam onto the bottom of the roof tiles, and we have to climb up the building and spray on top of the roof tiles or on top of the concrete deck.

In particular industrial buildings and low or high rise condominiums, but also normal houses which don’t have false or dropped ceilings, acquire outside treatment with sprayfoam.

Of course we can guarantee that after outside treatment of your roof, it will be 100 % waterproof for ten years as well, but it is of utmost importance that the layer of foam is coated with a sealant or waterproof paint, right after the foam treatment has been completed. This, to protect the foam against UV radiation and bird’s excrements, which can contain highly acidic fluids. These can damage the foam’s outer skin which in turn might cause deformation of the foam on the long term.

We at Sprayfoam Thailand do insist on applying this final protective coating ourselves, not only to prevent mistakes that may jeopardize the warranty of our product but also because it really has to be done immediately after we’ve finished spraying. Usually we come to an agreement in which the client pays for the supplies and labour needed to do the paint job only, no mark-up there.

For further information, please call or e-mail us.