Mansard Roof Attic Ventilation

Right now the roof top is the same as the sides shingles falling apart and i plan to put new iko 50 year fiberglass shingles on would have loved metal but can t afford it.

Mansard roof attic ventilation.

Intake vents located at the lowest part of the roof under the eaves allow cool. The roof is not flat small pitch not sure how many degrees and there is an attic that i can get to and almost stand up in so pretty large. If you are insulating with air permeable insulation material something like cellulose on the attic floor then my recommendation is to vent the attic. This creates a natural air flow by drawing in the air from outside pushing it up and out through the vent at the top of the house.

The total amount of ventilation area should be 1 300 of the floor space of the attic. The risk with an unvented attic is that you may miss a tricky air leak a hidden pathway from your conditioned space to this attic that leads to unexpected moisture accumulation in your roof sheathing. Cape cod style homes with no soffits mansard roofs or even vented roof deck systems are extremely challenging to properly ventilate especially with intake ventilation. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator. To make matters worse homes with existing soffit or undereave vents can have ineffective intake ventilation because their vents have become clogged with dirt or have been painted over. Step 1 add a vapor barrier. Enter square footage calculate or enter the square footage of the attic or area to be vented.

Soffit vents alone won t provide enough ventilation since the rising heat would get trapped under your roof without any vents on the flat part of the mansard. The most common way to add ventilation to an attic is by installing air intakes in the soffits and putting an outlet at the gable of the house. The incoming air can help push the heated air up out of the vents on the top of the roof. Modified bitumen roofing material should only be considered if the pitch of the upper roof is less than 4 in 12.

One of the best ways to protect your mansard roof from the problems of ventilation is to use a vapor barrier on the inside. To insulate the roof you will need to use a combination of insulation to fully protect the roof.