How the Spray Foam Insulation Process Works

Spray Foam Insulation Houston helps to protect against the biggest source of energy loss – air leakage – by creating an effective barrier. It also helps to prevent moisture and odors from entering a home.

It’s typically installed in new construction walls after running wires and plumbing, but before drywall is put up. It’s a quick and easy way to improve the energy efficiency of a home.


1. Preparation

Spray foam insulation is a mixture of two chemicals that expands when sprayed on walls, ceilings and other areas to be insulated. Unlike fiberglass batts or blown-in cellulose insulation, it creates an airtight seal that stops heat transfer between a home’s interior and the outside.

It also works to minimize air leakage, reducing energy costs. It’s the green building material of choice for achieving home energy efficiency goals.

Before the spraying begins, contractors prep the area to be sprayed. If they’re insulating an existing home, this means moving furniture, covering items that can’t be moved and putting up any drapes or curtains to prevent them from getting soaked by the expanding foam. Then the contractors can access all the walls to insulate them. They usually use special slow-expanding foam that allows them to accurately fill the voids in wall cavities without overfilling them.

If they’re insulating an attic, they need to move any items they can’t lift out of the way and cover them with plastic sheets or paint buckets to keep the foam from sticking to anything it comes into contact with. Contractors wear gloves to protect their hands and eyes, and they should avoid direct skin contact with isocyanates (the chemical that causes the reaction) to limit their exposure. They also wear respirators when working with open cell spray polyurethane that contains volatile organic compounds that can cause respiratory irritation.

During the spraying process, the two components of the spray foam come together in the tip of the gun. The “A” side of the system contains isocyanate and a blend of catalysts, while the “B” side contains polyol resin, blowing agent and other ingredients to give it its unique properties and characteristics. The combination of these chemicals is heated, balanced and sprayed through the applicator gun to generate spray foam insulation.

Some companies are starting to transition to low-GWP foams that are less likely to speed up climate change than the hydrofluorocarbons used in conventional spray foams. In the meantime, if you’re thinking about installing spray foam insulation in your home, ask the contractor if they use HFC-free insulation.

2. Spraying

Spray foam insulation is sprayed on to the areas of the home that need insulating. It’s a liquid that expands as it dries, filling all the gaps and nooks and crannies for an effective protective barrier. It’s important that the coat is even and thick enough for best results. If it’s too thin, the thermal protection is weakened. It’s also important to wear a full set of safety gear, including goggles and a respirator. You don’t want to get the foam in your eyes or breathe the fumes!

Foam insulation can be used on walls and ceilings, in new construction or as part of a remodel. For new construction, it’s sprayed in between wall studs after wiring and plumbing are run but before drywall or other interior wall material is put in place. It’s a quick and easy way to insulate the walls and make the house airtight. It’s also good for reducing sound transmission.

For existing homes, closed-cell spray foam is the preferred option because it’s more durable and creates a vapor barrier that helps prevent mold and mildew. It’s also a bit more expensive than open-cell spray foam, but it still offers better insulation per square foot than batts of fiberglass or cotton insulation.

Before starting the process, it’s essential to read and understand the manufacturer’s instructions for applying the spray foam insulation. This will ensure that you’re following the correct application techniques and ensuring that your product performs optimally. It’s also vital to prepare the foam canisters before mixing. Having them at room temperature is necessary to ensure that the chemicals mix properly.

During this phase, it’s important to keep the area you’re working in well-lit. This will help you see what you’re doing and avoid any accidents. It’s also a good idea to cover any stored items in the attic so they don’t get coated with the insulation.

Foam insulation that’s exposed in nonliving areas of a home (like an attic) needs to be covered by an approved thermal barrier. This can be drywall, mineral fiber insulation or specially formulated spray-on coatings.

3. Sealing

The foam expands and fills the space, sealing all nooks and crannies to create an airtight barrier. It also functions as an insulator and vapor barrier, keeping moisture out of the wall and preventing it from absorbing into the wood. It can also be used as a mold inhibitor and a fire retardant.

Spray foam insulation has an R-value of 3.7 to 6.5 per inch, so it’s quite effective at containing heat and reducing the amount of air moving throughout the building envelope and escaping through leaks. Increasing the insulation in your home is one of the three most cost-effective energy-efficiency measures you can take (sealing air leaks and adding mechanical ventilation are the other two).

Depending on the type of spray foam, it may contain a range of chemicals called prepolymers. These are typically a mixture of polyols, catalyst (primarily amines), hydrofluorocarbon or carbon dioxide propellant, surfactants and flame retardants. The ingredients of a particular product are listed on the can.

When contractors mix the components on site, they use a professional rig with a dispensing applicator gun to get an even mix and maintain the right temperature. The mixture is then sprayed onto the wall or other area and immediately begins to react. The resulting chemical reaction is what makes the foam expand and harden so quickly.

The foam has the potential to off-gas a disturbing concoction of volatile organic compounds, including formaldehyde and methylene diphenyl diisocyanate (MDI). Both are endocrine disruptors, carcinogens and bio-accumulative toxicants. The chemicals can irritate the skin, eyes and respiratory system. If exposed long enough, they can even cause chemical sensitivities.

Professional technicians wear personal protective equipment (PPE) when working with insulating foam sealants. It’s generally recommended that homeowners vacate the home during spraying and the curing process. This prevents exposure to the dangerous chemicals and ensures that the job gets done properly. After the foam has fully cured, it is safe to return to the home. It can take anywhere from five to 60 minutes for the sealant to reach a tack free state.

4. Drying

Spray foam insulation is a powerful air sealant that creates a custom barrier around ductwork and other penetrations, protecting them from moisture infiltration. It can also seal soffits and ridge vents, creating an airtight seal that reduces energy costs by limiting the movement of heat between the attic and living space.

The drying phase of the spray foam process can take up to 24 hours or more. This time frame is primarily dependent on the ambient temperature and humidity, which affect how quickly moisture evaporates from the surface of the foam. Raising the ambient temperature and lowering humidity levels can accelerate the curing process, while also helping to minimize the risk of mold or mildew development.

For the best results, installers should carefully monitor the temperature and humidity of the area where the foam is being applied. If the conditions are not ideal, product waste and equipment malfunctions are more likely to occur. This is particularly important during winter, when temperatures can drop for weeks at a time. Spray foam cylinder pressure drops as the temperature dips, and adequate pressure is needed for the spray to perform optimally.

Toxic fumes from the isocyanate-based chemicals in spray foam insulation can pose serious health risks for people exposed to them. It’s vital to follow proper safety procedures during the spraying and curing phases of the process, as well as ensuring that all employees are properly trained and protected.

It’s also important to ensure that any ductwork or other penetrations are completely sealed before applying spray foam, as this will help to prevent unwanted moisture intrusion. Once the insulation is sufficiently dried, it will be safe for use and can significantly reduce a home’s heating and cooling bills. Air leakage accounts for 40 percent of energy costs, and spray foam insulation is one of the few building products that can effectively seal gaps to cut down on energy usage. With this in mind, it’s important to choose a qualified contractor when installing spray foam insulation. They’ll be able to install it correctly and ensure that the insulation is properly cured for maximum effectiveness.