# Attached Carport Problems



## tinner666 (Mar 14, 2005)

Building it up so it's highest point is 1 foot higher and has it's own hip in line witht he existing hip would work fine. 
Gently remove 4-5 courses of shingles, and taper in some new rafters, then some sheathing boards, cover with 1" ISO insulation then glue down .060 reinforced EPDM,rubber, and reinstall the shingles and you'll be good for another 20 years or so.
You could also use SBS self adhered modified bit roofing, (nailable base, inter-ply, and cap sheet) and be good for another 10 years.
I have reactions to the EPDM glue, so I take a benedryl before I start glueing.


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## tinner666 (Mar 14, 2005)

I forgot. I use 3/4" 1x8 around the perimeter so I have a good nailable board for the drip edge and by time I use the cover tape, the edge is even with the 1" iso and there is no hump for the water to catch on.


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## tinner666 (Mar 14, 2005)

I also add a small piece of EPDM at the joint to help protect the roof itself from ice or anything else sliding down the shingles.


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## flatroofblues (Jun 13, 2012)

First of all, thanks so much for the response. I think I follow, the 1' higher would be where it attaches to the house. Could I get by without the ISO insulation maybe? I'm trying to make it all happen for around 1K, I know that's not very much when it comes to this kind of thing. Here's a quick mock up of what I was kind of thinking, is this what you meant having the hip line run with the house's? I'm wondering how to cut the framing also, it seem like it would be easiest to have the boards of the frame come to a point at the edge of the roof where the water runs into the gutters. Also since they have to span the full 14+' would I need a way to join two boards together or have a small support where the would both be attached? They would have a triangle shape from the side between the gutters and the roofing on the 3/4" 1x8 of the 14' side and that small side where it meets the house again. I'm really new to all this so please bear with me, thanks.


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## flatroofblues (Jun 13, 2012)

I was thinking if they had a support where the two boards spanning the 14' meet, it could help compensate for the fact the roof isn't perfectly flat anymore. They could be different sizes to adjust for the specific spot. Of course this is hoping that the board under the existing rubber and insulation material is useable.


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## tinner666 (Mar 14, 2005)

14' span calls for 2x6 rafters. You want them to taper to zero about an inch or so from the outer edge. Find the rafters underneath and run the new ones over top of those. NOT IN BETWEEN the existing rafters. 
To save even more money, and I can't properly explain this, taper the rafters so the outer ones cause the roof to flow downwards along the shingle area. You'll be up 1 foot at the hip, and almost none as you reach the gutter on both sides.
Failure to do so will cause you have two new gables that need to be trimmed out, one at each end of the flat roof.


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## tinner666 (Mar 14, 2005)

Or put another, maybe better way, slope it all directions so water is flowing to all the gutter areas on the 3 sides. Any better?


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## tinner666 (Mar 14, 2005)

Something like this. Actual layout can be changed, of course!:laughing: My drawing sucks!


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## flatroofblues (Jun 13, 2012)

That is actually just like the first drawings I did on paper for the roof! Haha. Okay, so I stretched the picture flat and drew this up with the rafters spaced about 2" apart. Obviously they will just have to go on top of wherever the old ones are like you said. (I'm assuming all these boards will have to be treated 2x6? I think I can get 16' 2x6s so they can all be one piece.)

So I peel the shingles up. (All the way to the sheathing board or just to the underlying material?)

Peel off the rubber and the fibrous stuff between it and the sheathing board over the carport (possibly removing the sheathing board if it had water damage? or should I take it off either way to loose the weight?)

Lay the 3/4" 1x8 (purple) around the perimeter. (depending on what I find under the rubber and existing drip edge, is it possible this won't be necessary?)

Run the hips (red outline), cutting them to stop and inch from the edge of the carport and attaching them directly to the existing hip and sheathing board. Also run the yellow outline (not sure the proper name) along the contour of the house roof to be able to attach sheathing board to it. (Is there a trick to getting all these angles right?)

Run rafters (blue outline) to about the same one inch from the carport roof edge.

Cover frame with sheathing board (do I need to bevel their edges where they meet the house-roof and each other?)

Cover with roofing material. (If I use self adhered modified bit roofing do I still need ISO insulation or can I skip it?)

This seems like it will be adding a good amount of weight, how can I know how much is too much?

Looks like we have a run of sunny weather for about a week so I'm going to start on Saturday. Tear up the rubber and see what I get. I'll post pictures of what's underneath if it get's weird. Thanks you so much, I know I have a lot of questions. I really appreciate the help, I've been really dreading this and I'm starting to feel more confident that I can do this myself.


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## flatroofblues (Jun 13, 2012)

Also could the yellow outlined boards be smaller than 2x6s?


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## tinner666 (Mar 14, 2005)

1. No need for treated lumber. No water should ever get there.

2. All the way to wood. The EPDM glue will react with any felt. Above the 'break', the EPDM will be your new felt.

3. I'd peel it off to eleminate any moisture issues. Only replace bad wood around the perimeter. Weight should be an issue. All weight will be on the ends of the rafters, on the outer rim, and close to the bearing wall of the house.

4. That goes on after the rafters. I like to run it 1/2" to 3/4" past the fascia to create a nice gap between the drip-edge and the gutter rear. Makes any future work or repairs much easier. If you're using 1" ISO, you can space the sheathing boards 1-2" throughout, but it must be tight at the main roof. 

More to come.


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## flatroofblues (Jun 13, 2012)

tinner666 said:


> 4. That goes on after the rafters. I like to run it 1/2" to 3/4" past the fascia to create a nice gap between the drip-edge and the gutter rear. Makes any future work or repairs much easier. If you're using 1" ISO, you can space the sheathing boards 1-2" throughout, but it must be tight at the main roof.


Which "that" do you mean, the 3/4" 1x8 (purple)?

Also I'm assuming you meant "Weight should(n't) be an issue", I'm hoping anyway lol


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## tinner666 (Mar 14, 2005)

5. Run the hips (red outline), cutting them to stop and inch from the edge of the carport and attaching them directly to the existing hip and sheathing board. Also run the yellow outline (not sure the proper name) along the contour of the house roof to be able to attach sheathing board to it. (Is there a trick to getting all these angles right?)

I've been rethinking that 1" deal. The EPDM dripedge has a 3" face. Run the rafters all the way out to the edge, but before cutting them, try to determine whether you think a 'zero' point will work as well as maybe 1" thick on the ends. The yellow line is a 'nailer'. Trial and error on the angles. 
The 2 longer hip rafters should be 2x8 as they will be carrying a larger load.


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## tinner666 (Mar 14, 2005)

flatroofblues said:


> Which "that" do you mean, the 3/4" 1x8 (purple)?
> 
> Also I'm assuming you meant "Weight should(n't) be an issue", I'm hoping anyway lol


 Yes to both. typing with one hand while holding dog for wife. Dog not happy.:laughing:


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## tinner666 (Mar 14, 2005)

flatroofblues said:


> Also could the yellow outlined boards be smaller than 2x6s?


 The angle will determine that. 'Flat' will need larger. 'Birdmouthed' so heel sits on roof sheathing can be 2x6.


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## tinner666 (Mar 14, 2005)

Cover frame with sheathing board (do I need to bevel their edges where they meet the house-roof and each other?) Yes.

Cover with roofing material. (If I use self adhered modified bit roofing do I still need ISO insulation or can I skip it?) You can skip it, but sheathing must be tight together,

This seems like it will be adding a good amount of weight, how can I know how much is too much? Not an issue.


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## flatroofblues (Jun 13, 2012)

I suppose now I should make sure that I can make all the necessary rafter cuts using a miter saw? Seems like I would need a table saw for proper beveling and possibly for where the main 2x8 hip rafters meet the existing rafters? Is it reasonable to try to pull off the large triangle shapes of sheathing with a circular saw or do I need to do that another way? Any specialty tools I should make sure I have?


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## flatroofblues (Jun 13, 2012)

I guess there should be a way to do the triangles with the table saw?


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## tinner666 (Mar 14, 2005)

Miter saw may work once you have the angles. Skilsaw is what I mostly use.

What do you mean by triangles? The 'drops'? (Cut off scrap pieces?)


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## tinner666 (Mar 14, 2005)

To be clear, I was discussing 1x material. You using OSB, or plywood instead? If so, forget the 1x8 perimeter board.


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## flatroofblues (Jun 13, 2012)

The triangle I meant were the triangles of sheathing I would need to cut to run to the edge of the hips, so I guess that would be the opposite of the 'drops'. I had planned on using OSB, is it better to use plywood?


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## tinner666 (Mar 14, 2005)

Ones about the same as the other for this application. 
The miscommunication was on my side since I use wood 99% of the time. Sorry.


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## flatroofblues (Jun 13, 2012)

Yeah I think for cost I will have to go with OSB, so then I should plan on the using the 1x8 on the edge attached ON TOP of the rafters and hip butted up against the OSB to make a flush slope, right?

Also do I run the 'nailer' first and then attach the hips and rafters to it rather than the house roof? Or do I cut the rafters to leave room for the 'nailer' to lay flush with them and the slope of the new roof?


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## flatroofblues (Jun 13, 2012)

So I found this awesome free autoCAD software google makes called "sketch up" trying to build my plan in it now. You can even pull building off google earth but it doesn't have my house for that option. If you have it on your computer I can send you the plan and you can explore it yourself if you like, it's a pretty easy and cool program, especially for free. Anyway I'll try using it to make sure I'm on the right page. So the way I've mocked it up here the place I've circled is the same distance into the roof as the other side, would it be better/more structurally sound to put that joint in the middle straight down from the house roofs peak, or does it not really matter? I'm sorry for all the questions, it seems the more I learn the more I have. Again, many thanks for all the info, I'd be lost otherwise


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## tinner666 (Mar 14, 2005)

I said earlier to forget the nailer. That's for use with ISO when using EPDM. It makes a nailer for the dripedge.
Just run the OSB 1/2"-3/4" past the fascia. That will be your surface for SBS roof material.


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## tinner666 (Mar 14, 2005)

"I've circled is the same distance into the roof as the other side, would it be better/more structurally sound to put that joint in the middle straight down from the house roofs peak, or does it not really matter?"
The nailer will be making a wide foot. That location, 1' up the rafter should be right over the outer support wall so that some or all of the pressure will be transferred directly to the bearing wall below, not in an unsupported portion of the roof.
Of course, that's an assumption. You have to open things up and adjust as necessary to the reality of what you find.
You want to be over the rafters, over the place they attach to the wall plate, on top of the bearing wall.
BTW, I have SketchupPro and still don't know how to use it.


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## tinner666 (Mar 14, 2005)

I sent you a PM.


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## flatroofblues (Jun 13, 2012)

I tried to PM reply but it said I can't without having posted 20 things? I'm off to work now but I'll call tomorrow if that's okay?


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## tinner666 (Mar 14, 2005)

Got them. We're good to go.


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## flatroofblues (Jun 13, 2012)

Is this how I should be planning on birdmouthing the hips? I read that you shouldn't cut out more that 1/4 way through. This would only give the roof a 5 7/8" rise over a run of 16', is that enough or do I need to go higher up the house-roof?


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## tinner666 (Mar 14, 2005)

Yes. And no. You'll need to run them down to 1" thick, of even to a complete taper. Get the flat roof dripe-dge with the 3" face and then calculate the thickness needed.

That 1/4 way rule will not apply because you aren't running any of the rafter beyond the existing fascia. Normal construction will have the rafter end extending as much as 32" past the birds mouth. Not applicable here. You might have an 18" long bearing surface in this scenario compared to a 3-1/2" birdsmouth on an exterior wall.


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## tinner666 (Mar 14, 2005)

I forgot to mention. If the birdsmouth did grow to 18", you'd want two nailers side by side to spread the footprint.


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## flatroofblues (Jun 13, 2012)

Okay, so I think I have it now. The contact is longer than 18" though. It would be 1 9/16" at the end so after the 3/4" nailer the drip edge would cover 1/2" down past the nailer. The drip edge goes on before the OSB if I'm understanding correctly. This would make the new pitch a 9 5/16" rise over a 14' 6 13/16" run.


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## tinner666 (Mar 14, 2005)

Nailers.
Rafters.
OSB.
Nailable Base. Folded over the outer edge.
Drip edge. Prime it with asphalt primer if I'm not mistaken. Ask the supplier to be sure what's compatible with your system.
Inter-ply. Cut flush with outer edge of drip-edge.
Granulated or even smooth Cap-Sheet. I like to run it a bit past the dripedge and fold it down a tad. Maybe an inch.


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## tinner666 (Mar 14, 2005)

I forgot to mention. If that rafter is much more than 1/2" thick on the end, you'll need a new fascia and all that that entails. I'm trying to keep this down to a new roof, not a complete rebuild. Get a piece of dripedge and scrap wood, to match nailer, rafter end and osb to check and verify appearance before proceding too far!


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## flatroofblues (Jun 13, 2012)

Oh okay, so I need to taper the rafters to 1/2" to avoid making a new fascia, so more like this? 3/4" nailer + 1/2" of rafter hip + 7/16" OSB should be thin enough for the 3" drip edge. It would make my rise more also. I heard if the rise isn't enough code will mandate a rubber roof


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## flatroofblues (Jun 13, 2012)

That makes the thickest part of the hip birdmouth 2 3/16", will that work?


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## tinner666 (Mar 14, 2005)

flatroofblues said:


> That makes the thickest part of the hip birdmouth 2 3/16", will that work?


 Yes. It's not a suspended load. The whole thing will bear on the existing roof. None of it will be carrying a load unsupported. You've got the idea now. 

On anither note, SBS is supposed to be rated for flat roofs with little to no drainage. 'Supposed to be'.
Depending on where you find the rafters hitting the wall plate att he upper end, you could feasibly go a bit higher if necessary to increase the pitch, but it doesn't sound or look as if that will be necessary.


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## flatroofblues (Jun 13, 2012)

Okay, so here's what I found. Only really 3 spots where the sheathing is no good. The to places where it attaches to the house and the middle of the long otter run. What's should I do about those? Everything that's part of the house seems solid. I know I still need to take up more shingles, I'm guess the old ones underneath them also, til I'm down to bare wood


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## tinner666 (Mar 14, 2005)

That long rotted piece needs to be replaced. The two smaller ones look as if they'll fall between rafters above and below. If so, they can be ignored. If you're looking to dot all the 'i's', you can repair those too.


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## flatroofblues (Jun 13, 2012)

So should I remove the new and old shingles to 3' above the new hips? Won't taking the old ones out make the new ones sit funny unless they're stacked two deep or something?


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## tinner666 (Mar 14, 2005)

flatroofblues said:


> So should I remove the new and old shingles to 3' above the new hips? Won't taking the old ones out make the new ones sit funny unless they're stacked two deep or something?


 Yes. They won't sit funny. Be very sure you have a tight fit where the new sheathing joins the main roof. You don't want a gap there for the roof to sag into. One thing could make them sit funny! You're doing 3 plies. Don't stop them all at the same place! Stagger them somehow.

I don't think we mentioned it, but using 1x8 nailers, over 1x12 sheathing, srew them down. Same with the rafters. An 8cc going through a 1x into another 1x doesn't have much holding power.


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## flatroofblues (Jun 13, 2012)

So do I still need to use two nailers next to each other on the perimeter or since I'm leaving the original decking can I just use one?


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## flatroofblues (Jun 13, 2012)

there are a couple of the rafters (there are 16 total) that look like this, not too bad but a little water damage. should i be trying to reenforce them or is it no big deal since there will be new rafters on the new nailers


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## tinner666 (Mar 14, 2005)

That rafter looks OK. If the decking is OK and you're not setting the new rafter between old ones. They must bear on a solid surface.


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## flatroofblues (Jun 13, 2012)

Okay, here's how far I got today. I'm starting to worry that I won't be done in time. It's saying possible rain on friday so I need a tarp plan for tomorrow night. With luck I'll have the rafters and OSB in by then.


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## flatroofblues (Jun 13, 2012)

Here are the end of the hip rafters, I tried to taper them to zero. Not perfect, are they good enough?


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## flatroofblues (Jun 13, 2012)

And the first nailer fell short of going all the way to the roof. That seems like it will be okay but I want to make sure. The next seem too thick where it meets the roof, or will it be okay?


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## tinner666 (Mar 14, 2005)

Pull strings from dots.


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## flatroofblues (Jun 13, 2012)

Okay, so after a long weekend of the roofers finishing and one rain that I tarped for successfully, it's all done! The first picture is how far I got on my own, the second is the finished roof. Had I known it would have been dry this long I might have tried to get further but I'm still glad I had someone finish for the actual waterproofing at the end. Just to have some one besides my self to hold accountable lol I ended up going over budget but still did all this for less than the first estimate to just replace the flat roof.

Thanks so much for all your help frank, the roofers who came to give me estimates all said I did a pretty good effort for a newbie and that's all thanks to you. Hope you are well and thanks again for everything :thumbup:


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## tinner666 (Mar 14, 2005)

Glad to have helped. Call again any time! Using the phone and posting pix to ask and answer in real time was the big factor.


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