I was talking with my framer about leaving a 1.5 in space between insulation and roof sheathing for ventilation, and the airflow from soffit vent to ridge vent. He then told me that above the top plate,between each rafter, should be blocking to provide stability for rafters. If this blocking is in place and comes flush with the top side of the rafters, how does air travel thru the soffit vent and up to the ridge vent ? Most of the airflow would be blocked. The 1.5 inch space would be useless if it is to be fed by the soffit vents. How do these 2 necessary components of good construction coincide. I need to know quick because the rafters are going up next week, and we were thinking of making changes that would affect the soffit vents. By the way, I am building a 2 story home in Alabama, approx 700 s.f. each floor, with a gable roof. Thanks in advance for the info.
Jcrew2
P.S. I am having trouble finding a supplier of Techshield in my area. Anyone know of a distributor that can deliver to Tuskegee, Alabama 36083 ? I have called Louisiana Pacific,left voice mail with the guy who supposedly works the area…still no luck.
Edited 3/8/2005 3:53 am ET by jcrew2
Replies
I've never once put blocking in around here in NJ but it might be code from where your from, so all your framer has to do is keep the blocking down 1.5" from the bottom of the sheathing.
What "Framer" said regarding the blocking.
Not sure about a Techshield source. Did you try thier e-mail address?
[email protected]
Good luck,
Steve
Vegetarian: Indian word for "lousy hunter"
You are the customer - Insist on it.
The only exception is if you are having Inynene or Rigid Foam blown into the rafter bays (i.e., unvented roof deck) nN that instance, the attic space becomes conditioned space - which is OK, esp if you are running your AC ducting up there.
For more info than you ever wanted, use the search function here to explore "attic venting" - also visit the buildingscience web site.
Enjoy your new home.
We use a product from Cor-a-Vent called Raft-a-Vent. It is a 1" tall strip that nails to the top of a block you can nail between rafters. I use a Senco roofing stapler to staple the strips to the blocks, but a framing gun works well too. http://www.cor-a-vent.com/RS-400.htm
Here is a pic of an application from last summer. The white strip is 1" tall x 1.5" wide x 22.5" long. http://pic9.picturetrail.com/VOL293/2163851/4419028/88311201.jpg
The March issue of JLC has an article about this -- pick it up.
Billy