I am getting ready to put up a shed style flat roof over my wooden deck on the back of my house and I had a question on how youd attach the roof to the existing house roof? The roof on the house is around a 7-12 pitch and with the deck floor being up to my first floor house level, I dont have enough head room to go right off the eave and do it that way, so I need to choke up on the roof to get my height and pitch. Is there a metal bracket made to attach to a ledger board. (I would lag bolt the ledger board to my house roof trusses to anchor that) I ask because the roof of the house being at such a steep angle makes the ledger board I attach to the house truss still at a goofy angle to attach the new truss supports for porch roof to? Did I explain that right?
I would only want the deck roof to be something like a 2-12 or 4-12 pitch.
I would only want the deck roof to be something like a 2-12 or 4-12 pitch.
HUBCITYSX
Member
I looked at the Simpson catalog (strongtie.com) and didn't see anything.
I'd rather see you gable the deck roof but I'll try to help.
Lay a 2 x 8 on the roof and find the angle of your shed roof. Cut that angleon the upper edge of the 2 x 8. Cut the angle of the face of the 2 x 8 plus the angle of the shed roof on the ends of your shed rafters. An L502 angle (simpson) will work if you nee a bracket. Use 2 x 4 braces between the rafters as close to the top as possible. Also you might want a dead leg abone the old eave area. You didn't say what type roofing you have, so I'll asume asphalt shingles. You will need to tear off 3'+ up the old roof and put down ice and water shield down before reroofing. This should stop ice daming, I hope! Hope this gives you some help. BTY I'm not a pro. carpenter but I run a lumberyard and have seen it all and done most of it.
Good Luck, Tim
I'd rather see you gable the deck roof but I'll try to help.
Lay a 2 x 8 on the roof and find the angle of your shed roof. Cut that angleon the upper edge of the 2 x 8. Cut the angle of the face of the 2 x 8 plus the angle of the shed roof on the ends of your shed rafters. An L502 angle (simpson) will work if you nee a bracket. Use 2 x 4 braces between the rafters as close to the top as possible. Also you might want a dead leg abone the old eave area. You didn't say what type roofing you have, so I'll asume asphalt shingles. You will need to tear off 3'+ up the old roof and put down ice and water shield down before reroofing. This should stop ice daming, I hope! Hope this gives you some help. BTY I'm not a pro. carpenter but I run a lumberyard and have seen it all and done most of it.
Good Luck, Tim
ok, I think I follow that, lay the 2x8 face down and cut the outfacing wide side to the angle and the ends of the truss to the angle and attach them, still bolting the 2x8 to my current roof truss and then just toe nailing the shed roof trusses to the ledger board?
Yes, I have asphalt shingles on house, I am putting a new roof on the entire house thats why I decided to do this at the same time so I can ice guard the whole thing anyways.
The reason behine using the shed roof style is that the house has a raised up flat roof style dormer, and if I were to go with a gable deck roof it wouldnt match the dormer. The section of roof where the deck roof would meet the face wall of the dormer. I will snap a few pics so you can see what i am dealing with, appreciate the advice. I hate wood, if you mess up you have to start over, with metal you can just weld it back up and keep going....LOL!
Yes, I have asphalt shingles on house, I am putting a new roof on the entire house thats why I decided to do this at the same time so I can ice guard the whole thing anyways.
The reason behine using the shed roof style is that the house has a raised up flat roof style dormer, and if I were to go with a gable deck roof it wouldnt match the dormer. The section of roof where the deck roof would meet the face wall of the dormer. I will snap a few pics so you can see what i am dealing with, appreciate the advice. I hate wood, if you mess up you have to start over, with metal you can just weld it back up and keep going....LOL!
HUBCITYSX
Member
Ok, I like your design with the roof meeting the dormer. Most times when people do this they have a steep slope dumping onto a shallow slope.
Post some pics or e-mail them to me (montanolbr@yahoo.com), I'd like to
see how it comes out. And yes I agree wood sucks!
Tim
Post some pics or e-mail them to me (montanolbr@yahoo.com), I'd like to
see how it comes out. And yes I agree wood sucks!
Tim
Send me a pic of what you want to do. Maybe I can help a little. Only have been in the housing trade for 10 years. Don't know it all but enough to keep in trouble.lol
A little know how
Mr700; I have a little know how in this department and you'll see the image (not a good one but you get the idea). You must carry the load on the outside wall & not the inside of your existing roof truss. Cause if you don’t you will have problems with the new roof once load is placed on it from snow/ice, as load is on it will raise the end up as it bows in the middle…
Mr700; I have a little know how in this department and you'll see the image (not a good one but you get the idea). You must carry the load on the outside wall & not the inside of your existing roof truss. Cause if you don’t you will have problems with the new roof once load is placed on it from snow/ice, as load is on it will raise the end up as it bows in the middle…
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HUBCITYSX
Member
theblues is right the dead leg needs to be in line with the outside wall. I didn't state that right when I said above the eave if there is an overhang.
Tim
Tim
Are you getting it inspected? If so, check with your local inspector for any special requirements first. This especially applies to what type of metal hangers you might need.
If not, we have just placed the the new rafters in line with the trusses or rafters on the existing roof of the house, cutting the appropriate angles and nailing or screwing them directly in place. You will find that the existing roof is likely not a perfect plane and thus the join line may wander a bit. Make sure that you cut the new rafters individually to fit and be level with each other so the new roof is straight. If you like the idea of a bond board (ledger) you can get a bracket that is close to the right angle. Usually these are used for tie-ins for 12/12 or greater pitches. I am not a big fan of the dead legs because it can create a teeter totter effect. Wood structures move quite a bit throughout their life, and you don't want a construct that will act as a lever.
Going from a 7/12 pitch to a 4/12 pitch is only about a 12 degree change, and going to a 2/12 pitch is still only about a 21 degree change. Anything less than 3/12 is more prone to condesation buildup on the underside, which can be annoying as it drips on everything below it.
The Ice and Water shield will not stop ice damming, but it can help keep it from leaking if you do have ice dam up. Ice damming is caused by a warm roof transistioning to a cold roof as it carries out beyond the living (heated) space. Sufficient insulation and good ventilation are the best way to prevent ice damming.
Oh yeah, just remember . . . Even if you cut it twice, it still may be too short . . .
If not, we have just placed the the new rafters in line with the trusses or rafters on the existing roof of the house, cutting the appropriate angles and nailing or screwing them directly in place. You will find that the existing roof is likely not a perfect plane and thus the join line may wander a bit. Make sure that you cut the new rafters individually to fit and be level with each other so the new roof is straight. If you like the idea of a bond board (ledger) you can get a bracket that is close to the right angle. Usually these are used for tie-ins for 12/12 or greater pitches. I am not a big fan of the dead legs because it can create a teeter totter effect. Wood structures move quite a bit throughout their life, and you don't want a construct that will act as a lever.
Going from a 7/12 pitch to a 4/12 pitch is only about a 12 degree change, and going to a 2/12 pitch is still only about a 21 degree change. Anything less than 3/12 is more prone to condesation buildup on the underside, which can be annoying as it drips on everything below it.
The Ice and Water shield will not stop ice damming, but it can help keep it from leaking if you do have ice dam up. Ice damming is caused by a warm roof transistioning to a cold roof as it carries out beyond the living (heated) space. Sufficient insulation and good ventilation are the best way to prevent ice damming.
Oh yeah, just remember . . . Even if you cut it twice, it still may be too short . . .
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