Ventilation in an attic is a key part of taking care of any roof, as there are a number of adverse effects improper ventilation can have on a roof. Roof ventilation can be accomplished in a number of ways, and proper ventilation can remove excess moisture from the air and disperse extra heat.
An improperly ventilated attic can rapidly climb in levels of moisture and heat, and damage either personal belongings or cause structural distress to the house. In this article, we’ll take a look at some effective ways of properly ventilating your attic, as well as some adverse effects you might experience from improper ventilation.
Roof ventilation, as with any type of ventilation, requires two components – intake ventilation and exhaust ventilation. Intake vents suck cool, dry air in from outside and are usually located at the eaves of the roof. Exhaust vents push out warm, moist air from the attic and are set along the ridge of the roof, or on the gables.
You can calculate how much ventilation you need with a Net Free Ventilation Area, which is the total amount of ventilation you’re getting versus the amount you need for your entire house. Keep in mind that things like insect screens or other blockages can significantly decrease your house’s ventilation capacity, and vents should be maintained like any other part of the house.
Improper roof ventilation can cause a wide variety of problems, some of them more significant than others. Sumps between rafters, often called deck deflection, can occur because after a period of time (usually at least several years), a plywood roof deck will deteriorate or warp as well as get spongy and walking on it can be dangerous.
This happens due to one side of plywood decking needing to be able to breathe by being exposed to circulating air. The adhesives in the plywood may deteriorate or dry rot can come about due to condensation.
The best thing you can do to make sure your roof ventilation is adequate is to measure your Net Free Ventilation Area and to get information from either your landlord or real estate agent regarding the suggested Net Free Vent Area.
If the numbers are at least close, you will probably avoid any ventilation related problems, but as we’ve shown, inadequate ventilation can cause numerous problems. The key to proper ventilation is making sure you have the right number of vents, and that they are all working properly.
Find out more by reading the full article which explains what you need to know about roofing systems.
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You need to install 2 roof vents spaced equally to ventilate the attic.
to get the pitch of a roof can you measure up thee rafter 12 inchs put a level across the mark and when its level you measure the gap.? say its 7 inchs from the bottom of the level to the mark on the rafter and that would be a 7/12 roof? is that the right way to do it?
wow all the sudden everyone becomes an expert huh just use a construction calculator if your to cheap to buy one then use the Hypotenuse formula and if didnt understand anything get someone who knows personally I dont like to use a framing square because its not exact on longer rafter remember each pencil line is almost 1/16″ thick
quick sqaure and recker lol
the bird mouth is alway a 3rd of the timber what ever and it alway the plumb cut is 90 % of your seat cut
This is the most ridulous way to lay out a rafter. You walk the rafter length out with the square and not measure from the ridge because the ridge height hasn’t been established yet. NEVER use square nuts because they come loose and you won’t realize it till after it is too late.Your birds mouth has depth cut requirements you just don’t measure 3.5″ for the wall plate your birds mouth is required to overlap your exterior sheathing.Hire a professional framer unless your building a chicken coop
Thank you for common sense, Other video’s were a bit confusing, Once again…Thanks
the pitch is 1/3rd not 8/12, the SLOPE is 8/12, he is usiong the wrong term, and the birdsmouth should be 1/3rd of the material, it dsnt mater what the plate is made of,