Most building codes require a ratio of 1 150 ventilation space to attic floor space.
Proper roof ventilation attic.
If you see dampness or frost you need better roof ventilation and some attic vents.
Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space.
Lowering the temperature in the attic can help reduce air conditioning energy costs and roof deck temperature optimize the service life of a roof covering and minimize ice damming.
Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge.
Rafter vents should be placed in your attic ceiling in between the rafters at the point where your attic ceiling meets your attic floor.
Effective attic ventilation systems reduce damaging heat and moisture in your attic promote energy efficiency by helping to reduce the load on your air conditioner in the summer and also reduce the risk of ice dam formation on your roof.
Attic ventilation serves two main functions.
The amount of space you devote to intake must be equal to the amount you allow for exhaust and these must be calculated according to the size of your attic and slope of your roof.
See the benefits of attic ventilation a new roof is more than just shingles.
Once they are in place you can then place the batts or blankets or blow insulation right out to the very edge of the attic floor.
To lower attic temperatures and to remove excess moisture.
Grab a flashlight and inspect your attic during the winter.
This is accomplished through the placement of ventilation near the bottom of the attic space at the soffits or eaves intake and at the top peak s or ridge s of your attic space exhaust.
You can calculate attic ventilation requirements by determining the square footage of your attic floor its width times its length and compare that to the total required net free area nfa.
For the best results place roof ventilation near the roof s peak and soffit vents in the eaves.
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.
Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.
The key to proper ventilation of your roof and attic is balance.
Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.
That said air resistance and interference such as vent grates reduces the area of true ventilation.
Proper ventilation necessitates that fresh air is able to find its way in the attic space while allowing stale air to get out.
Air flows in through the soffit vents and out through the roof vents.
