Can I spray foam the underside of my roof?

Open-cell spray polyurethane foam or closed-cell spray polyurethane foam (ccSPF) insulation can be sprayed along the underside of the roof sheathing to provide a conditioned and insulated attic space that can be durable and efficient in all climate zones (see Figure 1).

Should you insulate the underside of your roof?

In order to avoid damage to the roof deck, you should insulate ceilings to create an air barrier between the living space and an unfinished attic or airspace underneath the roof deck.

Where should you not use spray foam insulation?

Will spray foam rot my roof?

Studies show that open-cell spray foam is risky in colder climates. Indoor moisture diffuses through the foam and comes in contact with the cold roof sheathing. The spray foam traps the moisture against the roof, which results in eventual decay.

Is spray foaming your roof worth it?

If you see the benefit of insulating your new construction home correctly from the start for long-term comfort, energy savings month after month, and fewer headaches while you live in the house, then spray foam insulation may very well be worth the extra cost to you.

Unvented roofs - Closed cell vs Open cell Spray Foam Insulation which is better?

How do you insulate a roof with exposed rafters?

If your structure does not need to be well insulated, you can simply sandwich a layer of aluminum foil insulation or rigid foam between your finish ceiling and a layer of sheathing. Place the sheathing layer on top of the insulation and secure it with nails that pass through the insulation into the rafters.

What are the disadvantages of spray foam insulation?

Should I use spray foam insulation in my attic?

Closed-cell spray foam is a better choice for keeping subfloor moisture at optimal levels, while open-cell spray foam is a better choice for walls and attics, because it allows homes to “breathe.”

Does spray foam insulation cause wood rot?

It's a reasonable question to ask, considering that some homes with open-cell spray foam insulation installed on the underside of the OSB roof sheathing have reported moisture problems. There's also a pretty reasonable answer to will spray foam will rot your roof: No spray foam will not rot your roof.

Can you spray foam attic roof?

Spray foam contractors can install closed-cell foam between the joists to air seal and add insulation at the same time to the ceiling. All existing insulation and dust must be removed first to allow for a good bond. A minimum of 50 mm (2 in.) is needed; top up with other insulation afterwards.

Is it OK to insulate roof rafters?

Insulating between rafters will do no good, because the attic should be ventilated, and the rafter insulation would be between two unheated spaces. You can add insulation to the floor; the more the merrier. Just don't put it in the eaves. Also, make sure the attic is well ventilated.

How do you insulate a below ceiling?

A self-supporting ceiling is installed beneath the existing ceiling and insulation material is put in between (for example rock wool, fibreglass, PUR or cellulose insulation). Another option is to blow cellulose insulation into the free space between the floor and the ceiling below.

Can you insulate up against a roof?

Most building codes (including the International Residential Code) allow just one exception to these rules: in Climate Zones 2B and 3B, you can install fiberglass insulation against the underside of your roof sheathing without a ventilation channel or rigid foam above the sheathing — but only if you install tile ...

Does spray foam devalue your house?

In fact, according to Heritage House, they have seen entire roofs rotted and unrecoverable after SPF has been used. They state that by using SPF in your roof, '…you will devalue your home by the amount that a new roof will cost, and more. ' And we agree.

Can mold grow on spray foam insulation?

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.

How long will spray foam last?

With proper application, Spray Foam will last the lifetime of your home. Even roofing applications will last upwards of 30 years, with proper long-term maintenance. Spray Foam insulation adheres extremely well to virtually all substrates, and maintains its rigidity once dry.

Why you shouldn't spray foam your attic?

It Should Only Be Installed by Professionals

It cures with an exothermic reaction that generates a lot of heat, and if you put it on too thick, it can cause fires.

What happens if a roof is not vented?

Without ventilation, the attic will be warmer than the outdoor temperature, causing snow that lands on the roof to melt. As it drips down to the bottom of the roof, it will refreeze, forming dangerous ice dams. These can cause serious damage to your roof and gutters.

Can you spray foam an attic floor?

(Source: Building Science Corporation.) One technique that can both increase attic insulation and air seal the attic is to apply a layer of spray foam to the attic floor, then to install additional blown-in or batt insulation to meet or exceed insulation R-value requirements.

How do you insulate a sloped roof?

How can you insulate a sloping ceiling? If you want to insulate the roof, the first step will be to strip away the plaster and reveal the supporting beams underneath – usually wood. Your installer will then attach insulation board to the batons and then add new plasterboard.