Attic soffit but no exhaust
BentheThird
| Posted in Energy, Heating & Insulation on
I recently moved into an older (approximately 1970) row townhouse and will soon be replacing/adding insulation in an unconditioned attic.
The property has soffits. I was poking around in the attic just now and was unable to find any ridge vents or otherwise open vents. Shouldn’t I be able to see them from inside the attic. Does this mean I don’t have any?
I did notice at each one of the concrete walls (that separate the properties) a large in hole in the concrete walls.
Any thoughts would be appreciated
Replies
I'm thinking a hole between condo unit walls is a fire hazard
Thanks - I will look into that and see what the neighbors know..
What about the lack of visible outtake vents? Is that common in older townhouses (1970)?
I can't speak to how townhouses were built in Canada in the 70's but I do have some thoughts.
Yes, you should be able to see any vents from the attic. For ridge vents you would see a 1-2" slot in the decking cut out on either side of the ridge board. For static vents or turbines a hole (+/- 6-12") would be cut in the decking. For any powered or solar vent there would also be a hole but it might be obscured by a motor/fan assembly.
Is this a gable roof? If so, I would look for gable vents on either side of the structure. While I agree that the hole in the attic wall between townhouses may make it easier for a fire to spread, it seems to support the theory that the builder utilized gable vents for attic ventilation.
Ridge or upper vents are not a given. Their use makes venting easier and reduces the overall number and SI of venting required. Originally, Soffit vents on one side vented out for intake of Soffit vents on the other side. That is where the 1SF/150SF calculation comes from...just like crawlspace venting. With ridge vents, you reduce the need for active/directional wind to vent the attic and can capitalize on the stacking effect to increase/regulate flow. In a 'center townhouse,' the front soffits may be 'enough' to intake while the rear soffits are exhaling. Run the calcs yourself to see. Never put more ridge vents in than you have soffit vents.