rocfrk

I have an uncovered concrete patio off the back of my house I would like to cover. The cover I want is a cathedral that I would like to tie in straight back into the existing roof line similar to this (http://jhcustompools.com/images/District_G-20100908-00009.jpg). Problem is that the Roof would have to some how tie into the L shape on the left side. Is this possible. Are there any other options. I have see where the new structure was built higher on the L side and gutters were just added to the two roofs (see pic) but I would like to stay away from this if possible. Thanks for reading!

nealtw

In the valley between the two roofs you build a deflecter. If you can picture a triangle of plywood pointing at the gutter and wider as it goes back over the house. Right where the two roofs meet you install a rafter with a 3/12 or a 4/12 seat cut and what ever cut on the other end to fit the wall or roof at the other end. On each side of that one every 16" or 24" inches add another at the same level, each one will be short than the last.

TxBuilder

I agree with Neal. It's hard to explain in words, but hes on point here.

rocfrk

I think I see what you are saying, Kind of like adding a sloping "wedge" or "shim" in between the two peaks cut to a point at the bottom.
I appreciate the help!!!

TxBuilder

Exactly like that! Let us know how it works out.

nealtw

It is nice to be understud the first time out. But now theres more. These deverters are not the best looking part of the roof so we try to keep them as low as we can but they do creat a few problems. If one roof is higher or steeper than the other the water can run up and under the shingles on the lower roof, and with the amount of water in this area it will be the first to ware out. I would have a sheetmetal shop make one peice section for this with a raised rib at each valley. Extra big gutter and larger down pipe or evan two down pipes for that area.

BenjaminJohnson

If the slope is relatively shallow (less than 4" per foot) use a peel and stick underlayment under the shingles in lieu of standard felt (or often referred to as tar paper). Cover the whole deck with the peel and stick material prior to installing the shingles. Also, if you aren't going to re-roof the existing roof, remove enough shingles on the existing roof to allow the peel and stick to extend minimum 24" beyond the valley centerline. The peel and stick gives you and extra layer of waterproofing protection under the shingles and helps with what will be a relatively shallow valley. The material also has some sealing capability around nails.

If the sunroom is not conditioned space, you do not need to ventilate the roof. However, if the room is conditioned, you should try to install some type of ventilation and that is not easy with this type of add-on if you have a vaulted interior ceiing unless the space is open into the attic of the existing house so that you can install soffit vents that allow air intake flow through to whatever type of roof ventilation you currently have . If the space will not be open into the existing attic and you need to ventilate a valuted ceiling - good luck. If you can frame to create some cross ventilation space between the roof deck rafters and the ceiling joists you could install vents in the soffit and end wall(s) to allow for the recommended ventilation.

I hope this information helps.

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nealtw

The normal here for venting a valted or flat roof is to cross stap the roof with 1x4 or 2x4 and allow airflow from soffit to ridge above the insulation, on a flat roof you find outside air where ever you can.