Attic soffit vents (chutes)

[krisway]

I've seen some attics use the soffit chutes to help the soffit breath. Are these cutes only necessary when using blown in insulation? I'm planning on using batt insulation, so I can lay the batts and not block the air flow at the soffits. Just curious if I need these cutes or not.

 

[Steevo]

Any insulation that might block off the flow from soffit to ridge vent can be a candidate for the baffles.

In the case of batt insulation, installing soffit baffles will allow you to shove the insulation farther out over the wall top without closing off air flow, thereby better insulating a common cold zone at the top of a wall.

 

[JMURiz]

I used f'glass roll insulation and chutes to make sure the airway was totally clear. Figured I'd rather play it safe than have issues later.

 

[Falcon67]

The current idea is to use the chutes now made with a flap. The flap staples to the top plate and acts as a dam to keep blown insulation from dropping into the soffit. If you use batts, make sure that it lays over the top plate and does not block air over the top. HOWEVER - there is an effect call wind washing. Wind wash infiltrates the soffit and moves blown away from the plate and can move around and under unsecured batts. If you live in a high wind area and can use them, the trays with the flaps will block wind washing.

 

[KPSquared]

Like was said above, if you have any wind, they will channel all the air up and over the blown in or batts. If there is any chance at all of insulation blocking the eaves, then use them. They are WAY easier to put in BEFORE you sheet the roof and tend to be a pain in the *** afterwards. Either way. Cardboard or plastic. Don't know if it matters much.

 

[Falcon67]

http://spinspect.com/blog/?p=110

http://www.morrowinsulation.com/what-is-wind-washing/

 

[duke5572]

All the ones I've seen in new construction were made of foam and stapled up by the insulation crew after sheeting the roof. I like the idea of the flap mentioned in post #4---makes sense to me.

 

[Highbeam]

You staple them to the roof sheeting so do it after the roof is on but before the ceiling goes up. I've added them to an existing home and laying in insulation to staple them up is no fun.

 

[KPSquared]

Sorry. . .ya, the cardboard ones with the flap staple to the trusses. They fold down the sides. The big plastic ones staple right to the sheeting.

 

[Falcon67]

http://www.homedepot.com/Building-M...=-1&keyword=berger&storeId=10051#.UPSLrmfhfTo

 

[krisway]

Okay, so if I do use these soffit chutes then do I need to do in between each rafter? (My garage is 36ft long). Or can I just put 4 or 5 on each side of the garage?

 

[St-rider]

the proper way would be to do all of them.

 

[rsa]

the proper way would be to do all of them.

Yup.

Two informative, easy reads:

http://www.greenbuildingadvisor.com/blogs/dept/building-science/lstiburek-s-rules-venting-roofs

http://www.buildingscience.com/docu...s/resolveuid/b53082e3229e37734a779c742a6e0a10

Notice the prefab vents recommended in the second article are the same ones Falcon67 linked to.

 

[mark2457]

Yup.

Two informative, easy reads:

http://www.greenbuildingadvisor.com/blogs/dept/building-science/lstiburek-s-rules-venting-roofs

http://www.buildingscience.com/docu...s/resolveuid/b53082e3229e37734a779c742a6e0a10

Notice the prefab vents recommended in the second article are the same ones Falcon67 linked to.

2nd one was great. Thanks for sharing

 

[racerex]

I used the Accuvent baffles and I'm very happy with them. In my opinion, they're much better than those foam ones. I had to use one full baffle and 2/3rds of a second baffle to get me above the collar ties. The Accuvent baffle have the flap that staples to the top of the plate. You can order them online from Home Depot and have them sent to you or have them sent to your local Home Depot for pick up.

 

[racerex]

Yup.

Two informative, easy reads:

http://www.greenbuildingadvisor.com/blogs/dept/building-science/lstiburek-s-rules-venting-roofs

http://www.buildingscience.com/docu...s/resolveuid/b53082e3229e37734a779c742a6e0a10

Notice the prefab vents recommended in the second article are the same ones Falcon67 linked to.

Thanks for sharing. The second link gave me a few good ideas as to what I can do in four of my rafter pockets that have structural lumber that don't allow me to use the Accuvent baffles.

 

[k-os]

I used foam baffles on my single-bay side of the garage. Had to cut them a bit to fit around the 2x6 joists.