In cold climates the primary purpose of attic or roof ventilation is to maintain a cold roof temperature to control ice dams created by melting snow and to vent moisture that moves from the conditioned space to the attic ventilation acts to bypass the vapour barrier created by most roof.
Why are most attics in minnesota vented.
How much ventilation does an attic need.
Moisture resistance the attic will stay dry avoiding problems with mold and wood rot and thus can serve as living or storage space.
The starting point for any attic ventilation project is always what is the size of the attic space to be vented the international residential building code irc defines attic size in terms of its square footage length x width floor of the attic.
Unfortunately it s highly unlikely that the statements you hear will be true.
That said air resistance and interference such as vent grates reduces the area of true ventilation.
Let s take a quick look at the pros and cons of the vented attic system.
Once a contractor knows the attic square footage the amount of necessary attic ventilation.
A properly vented attic is very important.
In order to facilitate this exchange of warm and cool air the general rule.
Maybe you ve seen a fan in the side of your attic under the eaves or maybe you re aware of the ridge cap at the peak of your roof.
Generally speaking you need a ratio of 1 300 where for every 300 square feet of ceiling space you need 1 square foot of attic ventilation.
Many homes already have attic vents in place that can be used.
You re probably aware that most attics and roofs are vented.
Efficient especially if ductwork is in the attic rudd 2005.
Why proper roof ventilation is important.
In other words the entire vent opening doesn t count as vented space.
The most common mistake homeowners make when installing insulation is to block the flow of air at the eaves.
If you walk down to your local lumberyard and lean on the counter the employees and nearby customers will offer a variety of opinions about why attics need to be vented.
Disaster resistance roofs over unvented attics are less likely to be blown off in high winds because the wind cannot readily enter the attic.
The insulation will resist heat transfer into the house.
Roof vents and attic ventilation.
Inadequate venting in your attic causes all sorts of problems from wood rot to mildew peeling exterior paint rusty nails screws roofing problems and even energy loss.
Throughout the balance of this digest the terms attic and roof will and can be used interchangeably.
Venting ventilation home insulation contractors minnesota.
Most homeowners and builders believe that attics should be vented.