Hot Roof

Started by kenhill, August 27, 2018, 04:34:37 PM

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kenhill

Need to help son with his hot roof in Vermont.  Here are the layers starting from the ceiling to shingles:

The ceiling is 2x8 tongue and groove hemlock.  You can see rot near the eve.
Particle Board 1/2"
1x1" strips with fiberglass insulation in-between. 
plywood
tar paper
foam board
plywood
asphalt shingles. 

How should we re-roof?

Thanks.
Ken

Do these links work?

https://photos.app.goo.gl/Sfhgu2pG2zrsys8U8

https://photos.app.goo.gl/G9yTxVv3T4fmZrBc8

https://photos.app.goo.gl/cg3byAx5U5Ap67YRA


MountainDon

the links do not lead to images.  There is a trick to posting google user content to forums. Alas, I forget what it is... d*
Just because something has been done and has not failed, doesn't mean it is good design.


kenhill

Here is what I did based on the topic in the forum news:

"Google images can be difficult to use for forum posts. Try having the image open large on the screen and the right click on the image and copy the image address. NOT the url from the address bar."

MountainDon

Yes, thanks for finding that. The links work, and here is what can be done to post them in a message.   The routine is to follow the link you posted and then click on the image. That enlarges the image. Then do a right click and copy image address on that larger image.  Next, place the cursor in the new message composing field, find the 'insert image' icon (mona lisa) above the field and click it. Then paste that copied image address in between the img tags (the cursor should automatically be in the correct place. Paste. 








Just because something has been done and has not failed, doesn't mean it is good design.

Don_P

Repair or replace lower course of hemlock. It won't look good inside, consider total replacement.
Then typically tarpaper, foam with edges offset and taped, sleepers, osb, finish roofing


NathanS

Also just to add, no amount of insulation will protect a hot roof from ice dams and rot in Vermont. You have to ventilate on top of the insulation. At the eave and peak you should have a way to let the air in and out from between those sleepers.

You also want an air tight roof, don't let that warm air leak out from inside. Connecting the eave air barrier to wall would be an important detail... eaves are high risk. Also the black areas at the peak on the plywood look like there may have been air leakage issues up there causing mold and rot.

buildingscience.com has a lot of good info on doing it right and explaining roof failures.