Spray foam insulation usually doesn't go up against the roof sheathing directly. If it does it should've had a attic channel fitted first that lets the air move up along under the roof sheathing and out. If just the core of your house has spray foam ( walls and ceiling), then yes you still need soffet and roof vents.
After installing spray foam insulation in your attic, you'll need both passive and active ventilation. Some good passive ventilation options for your attic include roof edge and peak vents. For active ventilation, consider an attic fan.
Spray foam insulation will not prevent ventilation and so there's no need to avoid it thinking that it will result in mould and mildew from building up inside the attic space.
You can't leave it exposed to the inside of the building, so you'll need to use a thermal barrier to go over it, such as drywall or thermal barrier paint. What do we do? If you have an intumescent coating that has been approved, then you apply that over the spray foam.
As a product, spray foam insulation does not attract mold. And unlike wood or metal, spray foam does not rot, rust, or deteriorate. This means that an area properly sprayed with foam insulation will never become a food source or a hospitable environment for a mold colony.
Avoid using the foam near any ceiling lights or heating appliances. If you spray the foam near a ceiling light, for example, there is a chance that it could catch fire due to the flammable nature of the spray. Additionally, it could also cause damage to the light itself if it cures around any wiring.
Additionally, without proper ventilation, the air in the attic will be trapped and unable to circulate freely. This can cause moisture buildup and dampen everything from insulation to wood beams to roof sheathing. In cold climates, ice dams can be a serious issue, eventually leading to structural damage.
Spray foam is an ideal choice for insulating the floor of the attic because it is air impermeable and a powerful insulator. This will keep conditioned air in the living area of the home, and the warm or cool air in the attic from entering the home where it can cause condensation, mold and other problems.
A vapour barrier is not necessary with closed-cell foam but with open-cell spray foam such as Icynene®, it is sometimes required. Any air that migrates though a building envelope will carry water vapour. As Icynene® spray foam creates a seamless air-seal, it controls air leakage and the moisture in the air.
During SPF installation, other trade workers and building/home occupants should vacate the premises. Re-entry should be restricted until the product has finished curing, and the building has been adequately ventilated and thoroughly cleaned.
Air gaps are not the insulation. The foam is the insulation. You do not want any air gaps at all. Air gaps will promote condensation and lead to mold and mildew, which you do not want.
If you don't have soffit vents, we recommend you add some other vents in the lower part of the attic that can function like soffits. For some homes, you could try adding vents to a porch ceiling that could act like a soffit and feed the attic.
It's Too Airtight
Lack of proper ventilation can lead to superheating, carbon monoxide poisoning, and roof damage if spray foam insulation is used in the attic.
The water vapor in the air can often condense around the wooden rafters and beams that support the roof's structure, promoting the spread of mold and fungus that can lead to rotting. The best way to avoid this problem is with proper ventilation. Vents and registers are often installed on the soffits.
When you insulate the top of your attic with spray foam, you're bringing your attic into your home's envelope. As a result, you can reduce the temperature in your attic by a lot – anywhere from 120 degrees to around 95 during peak summer.
However, when you seal your attic with spray foam this keeps the warmth from the sun from penetrating the attic space and allows it to stay cooler longer. Unvented attic spaces are more comfortable to the homeowner, even during the cooler months.
Yes, you can have too much ventilation if it is the wrong kind, and if working against other vents. But for the most part, ventilation is good for a number of reasons. With this in mind, let's look at some myths and then some solutions to keep your attic perfectly ventilated throughout every month of the year.
Both types of spray foam insulation can last anywhere from 80 years to 100 years, with closed cell spray foam having a slight edge in terms of durability. For most families, this represents the lifetime of the house and then some!
Does spray foam absorb water? Yes, there are open cell spray foams on the market that will absorb water, but that doesn't mean they all do. The spray foam used here at RetroFoam of Michigan does get wet and water even moves through it, but it doesn't trap moisture indefinitely.
Generally speaking, it's recommended that a building remain empty for eight to 24 hours after insulation installation. We produce polyurethane foam and apply our spray insulation by combining two liquid components into the area to be insulated.
Spray foam can provide the thermal, air, and vapor control layers in both new and retrofit construction. Unvented roof strategies with open cell and closed cell SPF insulation sprayed to the underside of roof sheathing have been used since the mid-1990s to provide durable and efficient building enclosures.
Yes, you can sleep in your house after installing spray foam. However, the curing time for spray foam should be at least 24 hours after installation.
There are some instances where spray foam insulation has led to moisture issues, but it comes from the material not being mixed correctly, so it doesn't cure properly. The dry RetroFoam product is mixed with water, which leads to the misconception that the injection foam insulation will leave moisture in the walls.