Foam roofing has become increasingly popular in recent years. Despite its popularity, it does not come without its curiosities.
Below, we’ll take a look at some of the basics of foam roofing, so you can get more familiar with it before you plan to apply them in your place.
What is a Foam Roof?
Spray foam roofing is a completely watertight roofing system. It has three distinct parts, namely the silicone coating, the spray polyurethane foam, and the granules.
The foam is made by heating a combination of two chemicals that are pumped by way of a truck through a heated hose and then applied directly to the roof.
The foam grows thirty times its size and ends up about 1.5 inches thick.
However, the depth can be customized to each unique roofing system to create the slope needed for water to move toward draining systems.
Spray foam can be damaged by UV rays, so a silicone coating usually around 30 millimeters thick, is always applied over the top of it.
The application includes two coats, and the top coat is embedded with granules that provide plenty of strength and traction for walking.
Benefits of Spray Foam Roofs
Below are some of the benefits of a spray foam roof:
1- Easy Installation
Fewer roofers are needed to complete the job of applying foam roofing than are needed when installing conventional roofing systems.
The product used is also able to spray more quickly over penetrations such as pipes, HVAC units, and curbs.
Spray foam only takes about two minutes, while conventional roofing methods can take as long as half an hour.
2- Easy Maintenance
If a crack forms in a spray foam roof, you just need to cut around the area, dry it off, fill it in with caulk, and then smooth it over.
With conventional roofs, if water seeps into the insulation and moves horizontally, large portions of the roof will have to be removed to make the proper repairs.
3- Energy Efficient
Spray foam has a 6.6-inch per thickness R-value, which makes it the highest R-value per inch of any type of roof.
The higher the R-value, the less cool or heat can escape the building, which can save on energy bills.
4- Waterproof and Seamless
Since there are no seams in a spray foam roof, you don’t have to worry about water seeping into it. Instead, it’s all a single layer, so water won’t work its way into the system.
If the spray foam has a hole or crack, the water will only stay in that area instead of spreading around.
This is because spray foam is what is called closed-cell, so the water doesn’t have any room to migrate.
For water to get into a spray foam roof, a heavy, sharp object would be needed to break through the coating, granules, and 1.5 inches of spray foam, which is something that only rarely happens.
Once you’ve had the roof for a decade or two, you can apply another coating to keep it in good shape.
This is when you need to power wash the spray foam to get it clean and then install another coating right over the top of the original roof.
During this process, the foam is never touched and doesn’t give up any of its performance.
Problems With Foam Roof Coating
With all of its many perks, there are also a few drawbacks to having a spray foam roof:
Because the foam is quite light, it can easily get picked up by the wind.
In order to prepare for that, roofers will have to cover nearby cars and other areas to ensure it doesn’t stick to them.
If foam lands somewhere that it wasn’t meant to, it a be removed using a car detailing service that the roofing contractor pays for.
It can be chipped away using a clay bar or by exposing it to UV rays to allow it to disintegrate on its own.
2- Inexperienced Contractors Installing It
There are many professionals who don’t have any experience applying these roofs, which can lend itself to improper application.
Many just treat each roofing project as a way to test and see if they know how to do it, thinking it’s a simple process.
There are many ways you can distinguish a good foam roofer from a poor one, but the biggest indicator is whether they are certified with the SPFA or the Spray Polyurethane Foam Association.
3- It Must Be at Least 50 Degrees Fahrenheit to Install It
The temperature outside has to be at least 50 degrees to allow you to install the spray foam.
If you apply it in weather that is too cold, the chemical reaction that needs to take place won’t occur properly, resulting in the improper raising of the foam.
How Much Does a Spray Foam Roof Cost?
Typically, a spray foam roof will cost anywhere between $4.5 and $7.5 per square foot.
This means that if the roof is around 10,000 square feet, you can expect to pay between $45,000 to $75,000 for the entire project.
However, there are various reasons why the price could become fluctuated, including:
The further you live from the spray foam roofing professional you want to work with, the pricier the project is likely to be.
If you’re closer to them and they have less distance to travel, chances are it will be more budget-friendly.
b) Height of the Building
If you have a two-story-high roof and it’s simple to access, it will be much gentler on your wallet than if the roof is ten stories above the ground in a metropolitan area where access to the roof is difficult.
c) Existing Roof System
If you are working with a rubber roof, you can just use the spray foam right on top of it.
If your roof is held in place using stones or gravel, known as a ballasted roof, these stones will need to be taken away.
Because the roofing layer beneath the stone isn’t completely attached to the insulation, any fasteners or adhesive will need to be utilized to get the layer firmly stuck in place.
Only then can the spray foam be installed on top of it.
d) Existing Condition of the Roof
If a roof has a leak that allows water to enter the roof itself, it can get into the insulation and saturate it.
When this happens, those portions of the roof will have to be removed before the spray foam can be installed on the top.
If the roof doesn’t let much water through, then you’ll only need to remove a small bit of it before you can install the spray foam.
In short, the more of the roof that you have to remove, the pricier you can expect the project to be.
On What Roofing Systems Can You Apply Spray Foam?
Many homeowners and commercial business owners fear that they do not have the right kind of roof for spray foam roofing to be applied.
The truth is that there are some roofing systems that are perfect for the application of spray foam and some that need to be tweaked a bit before the foam is safe to apply.
Below, we will take a look at some of the most common roofing systems and whether they are ready for spray foam.
Spray foam can be installed right onto a gravel surface or smooth built-up roof because the roof is already fully attached to the substrate beneath it.
In order for the spray foam to be installed over a built-up roof with gravel, there is a wet-vac process that should be used to remove the gravel and stones to ensure only a smooth surface is left behind.
Spray foam is well suited to be applied to a metal roof as well.
You may need to apply a rust-inhibiting primer beforehand to prevent the metal from oxidizing if any of it has any rust on it.
One of the perks of spray foam for metal roofing is that these roofs have a crimped panel, which can leave open small holes for air and water to get into and out of the building.
Once the spray foam has been installed, it turns the roof into one continuous layer instead. This will do well to cover these areas of exposure and prevent water issues in the future.
You can install spray foam right over a TPO roof, so long as you have installed a cover board over any existing TPO beforehand.
It doesn’t matter if the TPO roof is fully stuck to it or attached mechanically; the cover board will always be necessary when installing spray foam over top of the TPO.
It is slippery, so for the best adhesion possible, this board is needed.
Spray foam is easy to install over any kind of modified bitumen roofing.
Since this type of roof combines in a convenient roll, whether or not you adhere or torch them down, it is ultimately a fully adhered roofing system that does not require a cover board.
Spray foam can be installed over any of the three kinds of EPDM roofs: ballasted, mechanically fastened, or fully adhered.
For a ballasted EPDM roof, you’ll first need to remove the rocks and then apply a cove board over it because there is nothing to keep the EPDM roof in place once the rocks are taken away. Finally, the spray foam can be applied.
For mechanically fastened EPDM, you must place a cover board down first before spraying the spray foam. Then, a fully-adhered EDPM roof is fine to simply install the foam right on top of it, given that the roof has aged at least five years.
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Jack Luis is a semi-retired painter who loved painting his clients’ ideas on their walls.
He had worked as a painter for over a decade serving customers in areas such as Charleston, Mount Pleasant, Beaufort, and Georgetown, SC (South Carolina). Today in his free time, he likes to read and write about the newer techniques implemented in his profession. You may read more about him here or get in touch with him here.