I had someone come look at adding insulation to the attic to help support a cooling system that I believe to be undersized. It is a dealer that has been in the area for as long as I can remember …. 20 years at least I would guess. And they are reputable as far as I know.
But he did give me pause when he said that the slope on my ranch house was too low for them to get a man in the soffits to install insulation baffles. He said they would blow in the celluse and gravity would cause it to settle down, creating a space for air to flow around the top of the insulation. Is this OK?? It sounded a little sketchy to me. He said it wasn’t a big deal anyway since my roof was ridge vented. I maintain the ridge vent is an exit and needs the soffit vent for air intake. Who’s right? How steep does a roof need to be to use vent baffles? I don’t know the exact pitch, but it is pretty typical looking for ranch. Easily walkable.
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Vent baffles we use are 4' long, we often cut them in half but you don't have to. They don't have to be stapled all the way so even a low pitch it isn't a big problem to install them. The issue is the amount of depth towards the exterior wall for insulation. The vent baffles allow that area to be filled as much as possible without restricting air flow. Simply doesn't make any sense that an experienced contractor would want to leave them out or would say they can't be done.
I'm not sure of the slope, I don't have plans and I don't know how to measure it. I took photos of the main roof gable and an addition gable ... maybe someone can tell by looking. I've called another insulator to come look at it.
I get 40 rise in 149 run, or about 3.2" in a foot on the main house. Accessible to a skinny kid, but not a beafy guy.
(BTW, you can estimate slope with a carpenter's square. Stand a good ways back and hold it at arm's length with the long side level and the outside edge of the short side centered on the roof peak. Raise it until the far bottom corner of the long side is aligned with the rooftop. Then read the rise on the short side. Divide by two for the typical 16x24 square. And for slopes greater than 8/12 flip the square.)
I agree ... baffles should be done. I don't think anyone would rightly every say that they would rely on the insulation settling enough to open up the vent channel. The baffle also prevents the insulation from being blown around (and removed from the area at the top of the wall) in strong winds. If you have no insulation now ... installing baffles should be straight forward (I didn't say easy). Choice of baffles may make it easier. I think the guy is being lazy ... and he shouldn't be if this is his chosen trade.
Measure the roof slope ... also you can use a 2 ft level and meas tape. Put the level against the roof and hold it level. Measure the distance at the low side to the roof. Half of that is your slope. My guess by looking at the pic is that it's a solid 4:12, but meas would confirm.
I've had to work in a lot of old attics and in the rocky mountain states I've never been in one that suffered from ill efffects of blown in insualtion blocking soffit vents- either fiberglass or cellulose. If I remember right even the author of Taunton's For Pros by Pros insulation book says he doesn't add soffit baffles unless forced to.
Personally I'd blow in r60 without baffles and not worry about it. If you were a client and we had to pass an inspection then baffles are a necessary or you won't pass. If you insist on baffles it will cost you more - they don't install themselves and it's dirty work.
As follow up, I had another insulation guy look at it. He said flat out they could install baffles, and his quote was signfificanlty below the other guys even with the baffles.