# EPDM Roof Plans



## tinner666 (Mar 14, 2005)

Go with EPDM. Buy 1" ISO insulation for underlay. It will prevent wood splinters, nails, etc. from poking holes. Since the buildings adjoin, get .060 Fire-rated. If you don't, you may find yourself re-doing it.I like to puta 1x8 plank arounf the perimeter to act as a solid nailer for the dripedge, then fill in with the ISO. It also acts as a 'step-down' to the cover tape that goes over the drip-edge so water doesn't pond.


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## tinner666 (Mar 14, 2005)

It seems I can't post pix anymore. Oh well.


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## tinner666 (Mar 14, 2005)

Had to re-boot. I couldn't even get smilies to work!

These are edges with the 1x8 surrounding the perimeter.

On your inside corners, fold, don't cut to get your fit! You'll have to prime, then glue each side seperately as you go. Use a practice piece first, second and third times! You ony get one chance!


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## stubits (Dec 30, 2008)

Tinner, thanks so much. Looks like you're down in Richmond, so not too far away. My wife's got family down there.

OK, so they actually make fire rated EPDM? Just making sure it is the EPDM and not the ISO that is fire rated. I should be able to get this from a roofing supply store, right?

Thanks for the tip on the 1x8 and the photos, very helpful.

I can adhere the EPDM directly to the brick, right? Does it require a different type of adhesive? Would you run it straight up the wall and under the parapet cap?

So, I will use a drip edge along the front edge where the gutter will be, but what do I do along the other outer edge, the longer one? Do I want to use something like a gravel stop?

Thanks!


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## tinner666 (Mar 14, 2005)

OK, so they actually make fire rated EPDM? Just making sure it is the EPDM and not the ISO that is fire rated. I should be able to get this from a roofing supply store, right? Yes


Thanks for the tip on the 1x8 and the photos, very helpful.



I can adhere the EPDM directly to the brick, right? Yes


Does it require a different type of adhesive? No. But, you do need to buy a rool of RM Strip to machanically fasten to the deck, at the wall. It self-adheres to the EPDM.






Would you run it straight up the wall and under the parapet cap? You can if it doesn't exceed 3'. If it exceeded 2', I'd prefer to machanically fasten it at 2', then mechanically fasten another piece under the parapet and have it overlap the lower piece. Or, it can be mechanically fastened with 'Term Bar' and caulked with the proper caulk 1' above the deck.



So, I will use a drip edge along the front edge where the gutter will be, but what do I do along the other outer edge, the longer one? 
Do I want to use something like a gravel stop?

If you don't water to go over that edge, use a gravel stop shaped piece.


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## stubits (Dec 30, 2008)

Tinner-

Thanks so much, this is all awesome advice.

So, when the EPDM goes vertical I should use something like this, right? Should it end up looking something like this? Do I need to install cant strips?

Also, where the EPDM terminates on the vertical, is this the correct method? What is the GenFlex Water Stop product their using there, I can't find it? What does it do?

It seems like the best bet for me is to run it up under the parapet cap. On the back wall, there is less than 1' between the roof and the cap and even way down on the bottom right, it is around 2'. This makes sense, right? How hard should it be to remove the parapet cap and get this up there? Will I need to replace the cap? What's your experience?

Then on the left hand side I will use a gravel stop, to avoid watering going over. The gravel stop gets installed like this and then specifically at the wall like this, right? Are all gravel stops as involved as in the first picture, or is there something simpler?

Along that front edge, I will install a drip edge and then a gutter, right?

And I want to install a 1x8 plank all around the roof, on all four sides, is that right?

Also, can I use a single piece of EPDM or will it be too large to be manageable? Probably, 10x12 or so?

Thanks so much!


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## stubits (Dec 30, 2008)

Bump.


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## stubits (Dec 30, 2008)

Hey Tinner. Thanks for all your help. Any thoughts on my last post?


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## tinner666 (Mar 14, 2005)

Sorry about the delay. I was out of town, then too busy and tired to check in. Sorry about that. 
Right on the first 3 links. On the forth, about the drip-edge, I nail to commercial specs of 4" o.c. I've seen too many of them flex and break the seal.
The last link is an optional method. I think I'd just forget that one. It just goes against the grain to poke hole along the perimeter and then pray the cover tape holds up.

You're looking good.:thumbsup:


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## stubits (Dec 30, 2008)

Frank-

You've got nothing to apologize for at all. I cannot begin to thank you enough for your help.

So, a couple more questions if you don't mind.

1) So, if that 5th link is optional, how do you handle where the gravel stop meets the wall?

2) What about link #5 makes it worse than link #3? They just seem pretty similar to me.

3) Since the roof is only 5x10, would you suggest using a solid piece of EPDM, so there are no seams? In my case maybe a 10x12 piece would do? 

4) I am up here in Washington, DC and it seems like the nearest distributor for Gen Flex is either Baltimore or Richmond, not impossible at all, but are there any other brands you like? I know you're not a fan of Firestone.

5) For the drip edge, gravel stop, etc., do you usually buy those at the roofing supply house or from a sheet metal shop? I don't need huge lengths and they seem like common materials, can I buy them off the rack, so to speak, or are they always custom?

6) Where the EPDM terminates on the vertical, this seems to be the correct method, but what is the GenFlex Water Stop product their using there, I can't find it? What does it do?

7) How difficult is it to work with an existing parapet cap/coping? Mine is older more than it is new and I am afraid of messing with it.

8) Have you ever worked with this type of gutter, one that has a flange? Seems like it would work well here and would do away with the need for a drip edge. Or do you always use a drip edge and then a standard gutter?

9) You mentioned installed a 1x8 nailer, just to confirm, it should be on all four sides, right? Does it need to be pressure treated?

10) This seems pretty straight forward, is it really? Is an EPDM roof really DIY-able?

Thanks for everything!!


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## tinner666 (Mar 14, 2005)

quote=stubits;428571]Frank-

Here we go.

So, a couple more questions if you don't mind.

1) So, if that 5th link is optional, how do you handle where the gravel stop meets the wall? I cut the front off, to whatever shape seems to fit the situation best, turn the flat part up about 3".

2) What about link #5 makes it worse than link #3? They just seem pretty similar to me. #5 is driving nails through the roof itself. The RM strip goes under the roof and seems to help with movement of the roof. No holes in the EPDM

3) Since the roof is only 5x10, would you suggest using a solid piece of EPDM, so there are no seams? In my case maybe a 10x12 piece would do? 
Absolutely! Seam, wall, drip edges and any 'detail' area is the bain of DIY'ers and pro's alike.
4) I am up here in Washington, DC and it seems like the nearest distributor for Gen Flex is either Baltimore or Richmond, not impossible at all, but are there any other brands you like? I know you're not a fan of Firestone. I've used Firestone. No headaches there. Look for the local Bradco Supply.

5) For the drip edge, gravel stop, etc., do you usually buy those at the roofing supply house or from a sheet metal shop? Roof supply store. Get the 024 aluminum, or whatever commercial thickness it comes in.
I don't need huge lengths and they seem like common materials, can I buy them off the rack, so to speak, or are they always custom? Off the rack, 10' is standard.

6) Where the EPDM terminates on the vertical, this seems to be the correct method, but what is the GenFlex Water Stop product their using there, I can't find it? Your supplier will direct you to the correct culk. Black Jack Neoprene, Geo-Cel EPDM, or equivalent. They all seem alike. 
What does it do? In the example shown, they're just sealing the edges until the adhesive fully cures. 
7) How difficult is it to work with an existing parapet cap/coping? Mine is older more than it is new and I am afraid of messing with it. Case sensitive is all I can say. Some are fine with mortar nails and termination bar. Some are so soft, they must be re-pointed by a mason, or you just glue all the way up and over and let the EPDM seal it.
I get to that point, I might go from plan A to plan H before I find what will work.

8) Have you ever worked with this type of gutter, one that has a flange? Seems like it would work well here and would do away with the need for a drip edge. No.
Or do you always use a drip edge and then a standard gutter? Yes.

9) You mentioned installed a 1x8 nailer, just to confirm, it should be on all four sides, right? Does it need to be pressure treated? Just the edges that get metal drip-edge. It won't serve any purpose along the wall.
Plain wood. If it's wet enough for PT, you have a big problem.

10) This seems pretty straight forward, is it really? Is an EPDM roof really DIY-able?Yes and Yes. Take your time. It's contact glue. It must be rolled in. You only get one shot. On small ones like this and there is no room to move, I'll only glue 1' to 18" of roof and EPDM, let it set and roll the EPDM in. Repeat as necessary. Your best bet is to lay it out, roll it back, and do some test runs WITHOUT GLUE until you feel confident. I have, especially on smaller awkward ones. Especially in the corners where pig-earing is necessary to figure out the correct fold. With EPDM, fold and try to never cut!,,,,,,,

Thanks for everything!![/quote]


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## stubits (Dec 30, 2008)

Wow Frank, thanks so much. You're great at explaining things... it is really making a lot of sense now and I am feeling more confident about taking this on!

I've got a couple of follow-on questions. 

1) I am still not understanding how to terminate the gravel stop. Do you have any photos, or know of any diagrams, etc?

2) When installing the gutter, does the EPDM get installed over or under the fascia board? The drip edge and the gutter get installed over the fascia board, right?

3) Regarding the parapet wall, if it does turn out to be a mess and soft, are you suggesting to run the EPDM up and over the brick wall OR actually over the parapet wall coping all together?

4) Also, totally unrelated, but I see you are an expert slate guy, is there anyway to clean roofing tar/cement off of slate. Our front roof is slate, but the previous owner or some workers must have spilled tar/roofing cement on it. The roof works, but isn't as attractive as it could be. Thoughts?

Thanks so much!!


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## seeyou (Dec 12, 2008)

stubits said:


> Wow Frank, thanks so much. You're great at explaining things... it is really making a lot of sense now and I am feeling more confident about taking this on!
> 
> I've got a couple of follow-on questions.
> 
> ...


I'll try to give Frank a breather for a minute.

1) I am still not understanding how to terminate the gravel stop.

Lap the EPDM over the fascia a little, so the excess will be hidden by the vertical leg of the gravel stop. Nail the gravel stop over the EPDM and then prime the roof flange of the gravel stop and apply a strip of uncured tape over the flange lapping back over the membrane. 

2) When installing the gutter, does the EPDM get installed over or under the fascia board? The drip edge and the gutter get installed over the fascia board, right?

Over - all three over.

3) Regarding the parapet wall, if it does turn out to be a mess and soft, are you suggesting to run the EPDM up and over the brick wall OR actually over the parapet wall coping all together?

Over the wall, under the coping.

4) Also, totally unrelated, but I see you are an expert slate guy, is there anyway to clean roofing tar/cement off of slate. Our front roof is slate, but the previous owner or some workers must have spilled tar/roofing cement on it. The roof works, but isn't as attractive as it could be. Thoughts?

I don't have a good answer for that. Frank?


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## tinner666 (Mar 14, 2005)

Sorry. I had to go out of town for a job. Thanks Seeyou!

I overlap the piece of gravel stop 4" with two beads of waterstop under the joint.

As for terminating at a wall, I cut and fold to see what efficiently closes any openings in a watertite manner that does not direct water into the home. And does not leave ANY gaps or edges facing up the roof.
Sorry I can't explain it any better than that. I can't even tell other roofers how I do it. I can show them, but still can't explain myself sometimes.

As fro cleaning the slate. 'Oops!' may work. Either scrape it off gently, or replace the slate. I believe I've detailed that on my site, but it's not for a rookie, or faint of heart.

About the nailer for the drip edges. I always extend it over the fascia and the rake 1/2". It gives a gap for installing gutter and on the rake, allows the water to drip as opposed to just run down the siding.


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## stubits (Dec 30, 2008)

No need to apologize for or explain the delay. You've been tremendously helpful and we've all got to make $$, no? Do you often go out of town for work or mostly stick around the Richmond area? Do you do much work up here in DC?

On the gravel stop, when you say you "overlap the piece of gravelstop 4"," what do you overlap it with, a piece of EPDM? 

Do you happen to have any photos of your work? Anything that shows how you've handled some of these terminations, joints, etc? It would be great to see how it is done correctly!

speaking of joints and terminations, how do you handle the corner where the gravelstop meets the drip edge?

Also, can I run through the order of things with you?

1) Install IPO and nailer.

2) Lay EPDM in place and allow to rest/warm up

3) Apply adhesive to roof top and to EPDM

4) Allow adhesive to set until no longer tacky

5) Roll EPDM onto surface

6) Install termination bars and and adhere EPDM to walls

7) Fold inside corners

8) Install drip edge/gravel stop

9) Install gutters

Am I forgetting anything major?

Also,

1) Do you have certain type of adhesive you prefer? Can I use the same adhesive for everything or something different on the walls?

2) Do you install the termination bars to the roof or to the wall? I see it can be done either way.

Thanks, as always!


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## tinner666 (Mar 14, 2005)

I think you have ot covered, with a minor exception or two.



stubits said:


> No need to apologize for or explain the delay. You've been tremendously helpful and we've all got to make $$, no? Do you often go out of town for work or mostly stick around the Richmond area? Do you do much work up here in DC?
> 
> On the gravel stop, when you say you "overlap the piece of gravelstop 4"," what do you overlap it with, a piece of EPDM?
> No metal butt joints. Overlap the metal pieces 4"
> ...


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## stubits (Dec 30, 2008)

OK, so I have a bit of a curve ball now.

In order to avoid having the vent this really small roof, the architect and I decided to seal the underside of the roof with spray foam, an allowable practice here. Long story short, this allows us to have a 3:12 pitch, rather than the 2:12 pitch. She is suggesting we now go with asphalt shingles. This website from the National Roofing Contractors Association indicates that 3:12 is the dividing line between "low-slope" and "steep-slope" and that we could go with either shingles or a membrane.

The plan would be to apply a layer of Grace Ice and Water shield over the entire roof deck and then to use a shingle that is specified for a 3:12 pitch.

What do you think? I think the install would be easier with less room for error.


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## AaronB (Jan 29, 2005)

As far as venting, is this a warm roof configuration or a cold roof configuration? I think if you really wanted to vent this space, then there could be some other methods rather than spray foam insulating. What would be the purpose of foaming the underside of the roof deck?

I'm a foamer, but foam is not a cure-all and I am having trouble figuring out the purpose.


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## stubits (Dec 30, 2008)

Aaron- Thanks for your input. The process we're using is best described in this link. As far as I understand the underside of the roof is coated with the code required amount of closed cell foam insulation (in my case about 7.5" for r-49)," converting the attic space into part of the conditioned envelope of the home and eliminating the need for any attic ventilation.

What are you're thoughts on this?


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## AaronB (Jan 29, 2005)

Do you have insulation on the ceiling? If so, then are you planning to remove the existing insulation? Is this going to be your building envelope insulation?


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## AaronB (Jan 29, 2005)

If it going to be your insulation, just apply it to the ceiling and leave your roof and put in some venting if you're going to use shingles and leave it as a cold roof. As long as you have the air space above the and below the deck, you will need to vent it. Best to keep the insulation on the ceiling and vent the roof, unless your roof deck is your ceiling, then no need to vent.

BTW I know that theoretically, 7 inches of closed cell foam adds up to R 49, but 4 inches of spray foam is max effective. After that diminishing returns sets in. 49 is a theoretical laboratory number that cannot be truly achieved.


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## stubits (Dec 30, 2008)

Thanks Aaron for the input.

This is new construction, a small 5x10 roof for an addition. In this case, the ceiling drywall will attach directly to the roof rafters(2x8). The plan is to fill that entire cavity, 7.5" with spray foam. R-49 is required by code, even if it is a mythical number!

So, will this work? Especially with a shingled roof? What are your thoughts on a shingled roof with a 3:12 pitch? We'll be coating the entire deck with ice and water shield.

Thanks so much!


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## seeyou (Dec 12, 2008)

stubits said:


> Thanks Aaron for the input.
> 
> This is new construction, a small 5x10 roof for an addition. In this case, the ceiling drywall will attach directly to the roof rafters(2x8). The plan is to fill that entire cavity, 7.5" with spray foam. R-49 is required by code, even if it is a mythical number!
> 
> ...


Most dimensional shingles are allowable down to 2/12 with I&WS on the entire deck. I've been doing it for 10-12 years with no repercussions. 

I see no problem with what you propose. In fact, I like it better than the EPDM solution.


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## stubits (Dec 30, 2008)

See you, just curious, why do you think this is the better solution? I am glad to hear it.

Also, aside for the I&W, do you do anythinf differently or special for the lower slope? Do you have a favorite shingle for the application?

Also, this is a shed roof style as shown in the drawing from an earlier post. I am not sure how to handle the flashing at the inside corner. Any thoughts?


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## seeyou (Dec 12, 2008)

why do you think this is the better solution?

I think a 30 year shingle will outlast EPDM for less money. 

do you do anythinf differently or special for the lower slope?

No.

Do you have a favorite shingle for the application?

I like Certainteed and Tamko products best, but product quality and representation vary from region to region. The shingles I get in KY probably come from a different factory than the ones you get in DC. 

I am not sure how to handle the flashing at the inside corner. 

The side against the parapet will be step flashed (one step flashing per course of shingles) and counter flashed. The counter flashing can be cut into the mortar joints and stepped up as the roof rises or cut through the parapet material parallel to the roof. 

The top will be flashed with an apron that lays over the shingles and the top step flashing and is counter flashed into the wall.


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## stubits (Dec 30, 2008)

See You- Thanks for all the help! So, you don't see any problems with how I plan to seal/insulate the roof?

Thanks for the info on the flashing. I guess I am just concerned at the corner where the parapet wall meets the top. Do I need to do anything special there? it seems like a possible intrusion point.

Thanks!


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## stubits (Dec 30, 2008)

bump.


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## tinner666 (Mar 14, 2005)

You'll have to 'box-fold the last piece of step-flashing. DO NOT CUT it. Practice with sheets of paper until you get the fold right. The termination/head flashing goes on next, then the counter-flashing.


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## stubits (Dec 30, 2008)

Frank, thanks! 

What do you think of going with shingles instead of EPDM here?

And can you explain the method for box folding please? Perhaps you have a photo or two?

Thanks!!


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## AaronB (Jan 29, 2005)

So you are spfoaming the underside of the roof deck in order not to vent the cavity between the ceiling and roof deck? That is not the purpose of unvented space.


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## stubits (Dec 30, 2008)

We are sprayfoaming the underside of the roof deck for two reasons,

1) To achieve the minimum required r value as established by code

2) To do away with the need of venting as it would be cumbersome and would interfere with the ability to properly insulate the structure.

This process is allowed by code here in DC and is done somewhat regularly. An explanation of the process can be found here.


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## AaronB (Jan 29, 2005)

SO then there will be no insulation on the ceiling?

I am aware of the practice.


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## stubits (Dec 30, 2008)

The drywall will be attached directly to the roof rafter, there will be no ceiling joists. The entire space between the drywall and the roof deck(7.5") will be filled with sprayfoam.

If there's something off about it, it would be good to know, but my architect is pretty certain about it, as are some of the local contracts I have contacted. Also, the material in the link I shared makes sense and seems authoritative. Perhaps I am explaining things wrong, but if this is horribly wrong, I'd like to figure it out.

Thanks!!


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## AaronB (Jan 29, 2005)

Nope, all good.


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## stubits (Dec 30, 2008)

Thanks Aaron, sorry I wasn't explaining things so well!

So, can anyone help me to understand the method for "box folding" indicated by Frank? Does anyone have any photos of this practice?


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## tinner666 (Mar 14, 2005)

Here it come. I took a flat piece of cardboard and bent it into the shape of a step-flashing.
Then I box folded it, kinda step by step. The angle depends on how your corner pitches meet each other.
The last step is to seal the inside of the fold to prevent moisture from getting into the crease and freezing in the winter.
I left one other optional step out. If it tries to unfold any, or you just want to really seal it off, fold the top onto itself to clamp it closed.


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## tinner666 (Mar 14, 2005)

I jusr remembered I have examples on my website on this page too.
http://www.albertsroofing.com/Metal Ridge Vent Details.htm

There are other helpful details on my site too. Feel free to browse http://www.albertsroofing.com/index.htm


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## AaronB (Jan 29, 2005)

The corner worries me, Frank.


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## stubits (Dec 30, 2008)

First of all, Frank, wow! Talk about above and beyond. Your pictures were perfect and extremely helpful. Thanks!

Aaron, what are your concerns exactly? Is there a better way to handle this corner in your opinion? Or is your concern about my attempting that corner DIY?

One thought, can I bring the dimensions to a sheet metal shop and have them design something? 

Thanks guys, for everything!


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## tinner666 (Mar 14, 2005)

I'm sure it's the rookie factor. Corners are critical and it's easy to build a leak into the roof.

It will need to be folded to fit, on site. It's almost how you would need to bend EPDM to close it's corner. Only difference is that with EPDM, all the sides would need priming, then, each detail of the fold would need to be glued seperately because it is a contact glue, and the fold would finish on the roof side, not out of site.
Thing is, flashings are never cut in critical areas. Unless you want to use copper and solder to fit. That requires another skill and mindset to do it correctly.
Here's an EPDM corner that looks like crap, but is serviceable. It's not glued because there was no room to work. Less than 2" above the roof deck, and 5" under an overhang with a valley dumping water there too. It should give you an idea.
We roofers prefer not to show our ugly solutions! When I do the upper roof this fall, I will make it prettier and even less visible.


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## tinner666 (Mar 14, 2005)

I'll have limited to no internet this weekend, so you might need to call me if you can't wait for certain answers.


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## AaronB (Jan 29, 2005)

The thing that worries me is the very point of the fold fatiguing and cracking open.


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## tinner666 (Mar 14, 2005)

AaronB said:


> The thing that worries me is the very point of the fold fatiguing and cracking open.


 A good point Aaron. These are confined to small pieces of step and corners, usually 8" long, 4" wide, 4" tall and I've never even seen an old one that failed. The only failures I've observed was when the applicator turned the fold the wrong way and lots of water was directed into the dwelling behind corners like 1/2 chimneys. And stubits, take note! If at first you bend it wrong, toss it! Do another. Metal can safely fold once. Not twice. Then, you WILL fatigue it.

In your case, the wall counter-flashing will hide the corner itself, the the termination flashing will hide (cover) it again. Any flexible sealant should be fine. Or, like I noted before, it can be folded shut on the top.


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## chimx (May 1, 2010)

Inside corners on EPDM are easy. Just cut a 12x12 inch piece of flashing, remembering to round your corners. Fold the entire piece in half. Take the remaining half and fold it again in the other direction, but only half way this time so that it looks like an "L". Take the corner of that "L" and shove it into the corner. Worth the inside transition in, and then the two faces of the "L". Now on the other side, slowly unfold the rest of your membrane on the opposing wall. They should meet at the corner. forming a "pig ear". Often times manufacturers want you to place a patch over the "pig ear" as well.

Don't worry about the fold cracking. That is the standard spec for EPDM. If you really are worried about it, put a patch on top of the fold. 

FIRESTONE DETAIL: http://www.firestonesp.com/bmt/files/videos/21_Firestone EPDM Geomembrane Installation Detail.pdf

--

I've done countless single ply roofs for commercial contractors. If you have a question feel free to ask.

edit: I just read the 2nd page and realized you are going with shingles instead and are talking about putting a corner on your tin shingles. ignore everything i said..


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