The building code lets you reduce that by half under some conditions but more roof ventilation is usually better.
Installing venting through cold attic.
If there s blown in insulation like ours rake back the fluffy stuff with a 3 or 4 ft long 1 x 6 or use a garden rake or hoe.
Attach the roof vent to the duct that is from the top of the roof.
You can attach the pieces together in all the holes by using the clamps that you have.
Try to keep it close to the fan location.
Start in the attic and drill a hole through the roof in the desired vent location.
The roof is vented by simple holes cut through the sheathing and protected with vent caps or by continuous ridge vents.
You will then install the dryer vent through the hole that you have just made.
You are then back to sticking the vent to the wall with the brackets and screws.
First determine your attic area by multiplying the length by the width.
Then aim for about 1 sq.
Your roofer will build this frame just a little larger than size of the vent leaving 1 8 inch of extra room on each side.
From up on the roof use a jigsaw or reciprocating saw to cut a 4 in.
Installation first requires a wood frame made of 2x4s installed from the attic between two studs.
The soffit vents are now installed but you still need to make sure there s no insulation blocking the new vents.
Having a vent in each side of the gable was the typical attic ventilation configuration in older houses but today it is considered woefully inadequate for an efficient house.
Install half of the required vent area in soffit vents.
There are different kinds of vents.
Use rigid metal ducting aluminum or galvanized steel with lengthwise seams facing up and joints sealed with foil tape or duct mastic or rigid plastic pipe.
If you vent through a soffit where attic vents are often located the moisture will get sucked back up into the attic or roof venting.
Adequate attic ventilation is important to reduce your utility bills and avoid damage to the roof and attic.
Leave the drill bit sticking through the roof so you can find the hole.
The number of vents in your roof will depend on the size of your attic.
Soffit vents the narrow horizontal section on the underside of your roof eaves.
In of vent opening per 150 sq.
The attic is usually colder than the rest of the house during the winter and that can create a problem for a dryer vent.
Attic for example has an area of 1 200 sq.
The standard is one square foot of venting for every 150 square feet distributed evenly between the soffit and roof vents.
A 30 x 40 ft.