Spray Insulation Attic Ventilation

I have read two articles by allision bailes that seem to contradict one another concerning whether or not a home or building that has spf should be ventilated or not.

Spray insulation attic ventilation. Properly designed ventilation can reduce airborne levels of aerosols mists and vapors generated during spray application and can help protect spf applicators helpers and others who may be working in adjacent areas. A combination of air sealing and insulating the attic floor while providing ventilation considerably reduces potential for condensation as warm moist air is less likely to enter the space and condense on cold surfaces. I am planning to use open cell spray foam insulation in my metal building and then build out the interior. Air sealing also reduces the natural ventilation rate or air leakage rate further reducing heating and cooling loads.

The spray foam insulation is protecting the layer of wool from cold while also trapping heat. Moisture is also another huge issue when it comes to spray foam insulation in an attic. The spray foam expands on contact filling up the space where it begins working immediately. A case of incompatibility.

Attic ventilation and spray foam don t mix that photo above is from an existing home that had spray foam insulation installed in the attic over the master bedroom. It has been said that insulating with spray foam insulation at the roof line will lead to moisture problems with the roof sheathing. But with spray foam ventilation is not an issue. Too often mechanical ventilation ducts from bathrooms kitchens or laundry rooms deposit warm moist air into the attic instead of outside the building envelope.

Spray foam from home logic is an excellent insulation type to choose for the attic. The ventilation system is still in place behind the spray foam as the ventilation card has been installed. That is now a conditioned part of your house just like any room in your. But then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents.

Now we use attic ventilation when we use products like fiberglass because we have to manage the moisture. Whereas too little spray foam insulation can leave for thermal bypass because of the complete lack of insulation in the attic. Becoming more affordable significant long term energy savings sealing restricts air movement through the building envelope. A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits.

One article was entitled spray foam insulated homes need ventilation posted on oct 22 2014 by allison a. What you re looking at there is the place where a power attic ventilator had been.