changing pitch on roof

hunter · 05-16-2009, 07:42 AM

im considering changing my roof pitch, i have a roof pitch of 3/12 i wanna rasie it because when ever it rains heavy it backs up on the shingles and leaks, the roof shingles are arch- shingles , they are about 7 years old but they where not overlapped correctly if im going to bother with re roofing it im thinking of raising the pitch, also i would like the look of a little bigger pitch, any suggestions on how to do this

GBR · 05-24-2009, 09:52 PM

Draw up the rafters, materials, cut views, elevation views, and top, blueprint, view. Have a Structural Engineer review it, put his stamp on it, and submit it to your local Building Department for their safety inspection. Order the material, go to it. Enjoy. Be safe, G

WallyPop · 07-25-2009, 06:37 PM

Seems to me you'll be spending big bucks, capriciously. As u think about it, this would make sense if u decided to raise the pitch high enough to to have a walk-in attic,etc.

The other over-riding criterion, you must just have the look you desire. Can't rationalize that.

If stopping leaks is the only real objective, tear off the old shingles (wait until you check on the disposal fees) and install new shingles. I'm presently doing a dual pitch, 2:12 and 4:12. The latter is applicable for standard shingles, I'm using GAF's asphalt TimberLine; the 2:12 slope uses the same shingles but GAF issues special install instructions to prevent rain backup, etc. You can do it or get a pro.

If the sheathing is in bad shape then remove all the sheathing and at that time consider sistering longer rafters to your present ones and get the increased slope you desire. Then shingle.

Just my opinion since I've been agonizing over a similar project for 9 months. You, at least shouldn't have to add any bearing wall reinforcement, like I did. (P.E costs.)

Good luck.

oldog/newtrick · 07-26-2009, 08:13 AM

Hunter, changing the roof pitch properly will be a big cost factor. I would suggest tearing off the shingles, installing a underlayment such as Weather Watch on the entire roof slope and then installing a good 25 year 3-tab shingle. A 3-tab will seal tighter than a dimensional shingle plus you loose the visual view of the shingle on a low slope roof and tend to see the bottom of the shinle and not the laminate and shadow line.

There are products available that are slope specific that will prevent water intrusion if properly installed. If you have any questions stop by you local roofing supply house and talk to a salees rep about your situation, they should be more than happy to help you choose the right materials to fit your needs.

earlgrey · 12-22-2009, 05:11 AM

Here in PA we are required to use snow and ice shield (a rubber self adhesive membrane) under the shingles just around the perimeter and in valleys, but when I have a low pitch I ice shield the entire roof and I've never had a call back!

oldog/newtrick · 12-22-2009, 02:09 PM

As Earl stated shingles may be applied to a roof slope of 2/12-4/12 if a weather watch type underlaymrnt is installed on the low slope roof deck. A pitch less than 2/12 pitch must have a covering other than shingles.