Rafter insulation baffles

[Donald]

So I had a roofing company come today to inspect my roof that was done summer 2024 by a "recommended" roofing company. Now out out business.

I mentioned my power roof vent motor had failed after a year. He said maybe the soffit vents are not as the should be. The power roof vent was spinning it's wheels with no intake air.

It looks they insulated the 2nd floor ceiling and then tried to push in some cheap baffles. But in many cases the fiberglass is blocking the air flow to the baffles.

I have one in ones or similar to the first picture. Maybe replace with better ones in picture two.

Live and learn.

 

[JohnnyG]

Yes. I had those installed on one of my last homes. They definitely work as claimed.

 

[supton]

Can't crush the foam, have to have an air space. Also the soffit vents have to be good sized. The small 2 or 3 inch diam holes, once you put a vent over them, do not flow that much air. That's my recollection from when I looked into it, years ago, as I had all sorts of roof problems. [My fix? move!]

 

[Donald]

Yes. I had those installed on one of my last homes. They definitely work as claimed.

The ones in second picture.

 

[CorvairGeek]

A leaf blower is good to blow the insulation out of the soffits on a single story house. Idiots had filled them on a house we just purchased.

 

[Donald]

A leaf blower only works for blown in insulation.

 

[BMWTurboDzl]

Sounds like they crushed the baffles by pressing too hard with the insulation. Another method is to hand cut rigid foam and the cut little pieces of foam to place against the underside of the roof deck (attached to the rafter) and you then attach the rigid foam baffle against the foam blocks and air seal the edges with spray foam.

The HD baffles work but obviously if the rafter spacing isn't consistent it becomes and pain. My rafter spacing was wildly inconsistent.

Powered roof vents are unnecessary btw.

 

[Donald]

Sounds like they crushed the baffles by pressing too hard with the insulation. Another method is to hand cut rigid foam and the cut little pieces of foam to place against the underside of the roof deck (attached to the rafter) and you then attach the rigid foam baffle against the foam blocks and air seal the edges with spray foam.

The HD baffles work but obviously if the rafter spacing isn't consistent it becomes and pain. My rafter spacing was wildly inconsistent.

Powered roof vents are unnecessary btw.

If you have a non normal roof shape and the linear feet of the ridge is not adequate for the square feet of the attic area then what do you do. Power ridge vent.

 

[MyWifesBoyfriend]

Do you have condensation in the attic? It would be quite apparently if the soffit vents were blocked.

 

[BMWTurboDzl]

If you have a non normal roof shape and the linear feet of the ridge is not adequate for the square feet of the attic area then what do you do. Power ridge vent.

What makes you think you needed a power ridge vent? Your roof wasn't built to code?

https://www.greenbuildingadvisor.co...owered-attic-ventilators-are-a-waste-of-money

 

[Donald]

What makes you think you needed a power ridge vent? Your roof wasn't built to code?

https://www.greenbuildingadvisor.co...owered-attic-ventilators-are-a-waste-of-money

This section of the attic let's say is 30' X 30'. But the ridge is only 12' in length. So the ridge cannot provide proper ventilation. Not enough linear feet.

Around here a lot of newish houses have a lot of funky roof lines. Not like colonial houses in New England.

 

[BMWTurboDzl]

This section of the attic let's say is 30' X 30'. But the ridge is only 12' in length. So the ridge cannot provide proper ventilation. Not enough linear feet.

Around here a lot of newish houses have a lot of funky roof lines. Not like colonial houses in New England.

View attachment 315842

Not necessarily. You want slightly less at the ridge to pressurize the attic.

https://buildingscience.com/sites/default/files/migrate/pdf/PA_Crash_Course_Roof_Venting_FHB.pdf