Spray Foam Attic Ridge Vent

In typical construction and climates building code tables can be followed when using spf as an insulation and air seal.

Spray foam attic ridge vent. All insulation materials require proper venting. One of the biggest benefits of using spray foam is to get greater airtightness. They are holes in the insulation. Spray foam is applied directly where it s needed ensuring that any ventilation vents are left untouched.

Cathedral roofs especially need a lot more insulation between the ceiling and the rafters because there usually isn t any attic space. The attic you see in the photo here is a different home but it does have one feature in common besides the spray foam. Rigid foam and spray foam are two of them. This section of the code also describes the use of thermal barriers it seems like the radiation of heat through the windows would make the attic hot.

Sorry photo did not come out. Intumescent coatings are not always needed to coat spray foam in the attic in order to meet code thermal barrier requirements. If you look closely you ll see two exhaust flues on the left side. Actually you should probably get rid of power attic ventilators whether or not you re sealing the attic but that s another article.

The two products most often used in an unvented attic assembly are medium and low density sprayed polyurethane foam spf. Building codes provide for the use of spray polyurethane insulation in the foam plastic section. Heat from the house rises up to the attic but when there isn t one the heat rises up to the roof. The spray foam expands on contact filling up the space where it begins working immediately.

Inspected a house yesterday with spray foam insulation in the attic. Windows in a conditioned attic are similar to windows in your home. The installer sprayed foam directly on the metal flues. You ll also see another safety hazard and code violation.

A ridge vent was still present. That means you get rid of all attic ventilation whether it s passive ridge gable soffit vents or active fans. One of the most common reasons to put spray foam on the roofline is to avoid having to air seal the attic floor because the attic is connected with the air in the house and indoor air is more humid than outdoor air which can cause moisture problems. Normally in occupied areas all spray foam must be covered by a 15 minute thermal barrier such as thick drywall per code requirements in irc section 316 4 and ibc section 2603 4.

You should never do this.