EPDM to Composition in Colorado Monsoons

[John Svoboda]

I need some guidance with an EPDM to asphalt shingle transition.

DEAD flat EPDM. Top course of shingles appears nailed right through EPDM. Leaking badly under recent record rains. Feels like EPDM was laid straight over sheathing or maybe a little felt or something- not the padded feel I believe correct underlayment provides.

I know this is wrong, even if I can't see exactly what was done, but what is right? Custom flashing to match roof angle and what? Firestone guidebook solutions all involve some sort of bead developed at the edge transition (and they assume 90 degree edge) which is obviously going to be a problem with more ponding.

Does UBC ever allow dead flat? I thought not. What are the circle and square impressions showing-through in the second pic? Some sort of adhesion pads?

Thanks in advance.

JD
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[Raymond Wand]

There should be a flashing cap (metal) where the EPDM meets asphalt. Its missing nor is the EPDM installed correctly as shown in photo.

The circle and square impressions are metal disks used to secure the substrate (usually tar board) under the EPDM down to the roof decking. Its done that way usually when EPDM is laid over an old built up roof (tar and gravel).

[Raymond Wand]

John

I couldn't find the specific details for the transition from flat to asphalt at the link, but a great resource none-the-less.

EPDM Mechanically Fastened Roofing System | Johns Manville (http://www.specjm.com/products/system.asp?system=epdmsingle&type=mechanically&main=engineering)

[John Svoboda]

Thanks for the help. It's new construction, as of 10 years ago.


John

I couldn't find the specific details for the transition from flat to asphalt at the link, but a great resource none-the-less.

EPDM Mechanically Fastened Roofing System | Johns Manville (http://www.specjm.com/products/system.asp?system=epdmsingle&type=mechanically&main=engineering)

[John Kogel]

Dead flat does not have to leak. Water will find its way off. But if the roof deck starts to sag, then it is no longer dead flat, and we end up with ponding. :(
Since you posted questions about this roof on another forum, I looked up a roof I inspected which is dead flat and located near the rain capital of the world, the Pacific North West.
1, EPDM was a poor choice because of the problem you are seeing. An edge flashing must lap over to hold the membrane down. Then it will leak at the fasteners. Your roof is not even installed properly so it is not surprising it is leaking. If you have insurance, a roofing professional will hopefully report what we are telling you - that roof is kaka.

Here are the pics of a flat roof that is working well. Torched-on modified bitumen is lapped down over the fiberglass shingles and simply sealed tight to the shingles. They laid 2 layers on a plywood roof deck with staggered laps, Ridge shingles were added along the sides and front to create the illusion of ridges, but the back side was left open to shed water.

Getting up there was a challenge. :biggrin:

[John Svoboda]

Thanks John and for including the pics. Are you suggesting this as a solution for me? Do you think it would work considering the channels/valleys inherent in the asphalt shingles, as opposed to the much more smooth/flat fiberglass of that roof? My roof deck is not sagging at all. There is minimal ponding.

Oh, yeah, I've got tons of folks who tell me it's messed up and zero who can tell me what should be done other than completely rebuild it at the cost of a Camry. Had three roofers look at it, including the guy who built it, and their advice adds up to a big shrug. How do I find a roofer who knows how to do this right? Last time I asked a GC I know well and that led to the shrugging guys. Roofers are generally the knuckle-draggers of residential construction in Colorado. Asking them to devise a solution is like asking my dog to do my tax return.

ALL insurance policies specifically exclude construction defects. I've got damage to the interior caused by this roof that will not be covered again. Adjuster looked at the roof, told me it was wrong and, once again, offered nothing on what would be right. That's why I'm here.

Thanks again.


Dead flat does not have to leak. Water will find its way off. But if the roof deck starts to sag, then it is no longer dead flat, and we end up with ponding. :(
Since you posted questions about this roof on another forum, I looked up a roof I inspected which is dead flat and located near the rain capital of the world, the Pacific North West.
1, EPDM was a poor choice because of the problem you are seeing. An edge flashing must lap over to hold the membrane down. Then it will leak at the fasteners. Your roof is not even installed properly so it is not surprising it is leaking. If you have insurance, a roofing professional will hopefully report what we are telling you - that roof is kaka.

Here are the pics of a flat roof that is working well. Torched-on modified bitumen is lapped down over the fiberglass shingles and simply sealed tight to the shingles. They laid 2 layers on a plywood roof deck with staggered laps, Ridge shingles were added along the sides and front to create the illusion of ridges, but the back side was left open to shed water.

Getting up there was a challenge. :biggrin:

[Raymond Wand]

John

Here is how my roof with EPDM has been done at the eaves and something similar should have been installed as per your concerns. 29430

[John Kogel]

EPDM has a projected lifespan of over 50 years, so I think you want to repair the edge of that membrane with a metal curb such as Raymond's. But those fasteners showing through the membrane need to be dealt with too, because those will be leaks very soon.

If the membrane can't be salvaged, then, yes, check out the torched-on membrane approach. After the upper row of shingles is removed, the membrane can be torched directly on to your shingles, no problem. Those are similar to what we use here.

[Raymond Wand]

Fwiw, Any EPDM systems I have seen have had the ghosting of the fastener making it noticeable. My own roof is the same.

UltraFast Fasteners and Plates - Roofing Materials | JM (http://www.specjm.com/products/roofing/ultrafastfasteners.asp?system=epdmsingle&type=fully)

[John Kogel]

Thanks, Raymond. Fasteners don't cause wear of the membrane? I don't know, because we seldom see EPDM and when I have seen it, it was installed by cretins.

[Raymond Wand]

Good morning John and John,

Wear can only happen if there is foot traffic. So one must be careful not to step on the fasteners.

Standard Attributes | EPDM Roofing Association (http://www.epdmroofs.org/what-is-epdm/why-epdm/standard-attributes)

See picture 2
New EPDM Roofing Pictures and Photos (http://www.homeadvisor.com/resources.dg.project.New-EPDM-Roofing.35.57.61558.html)

[Peter Louis]

Great pictures.

Hi, John the pic 3 ridge cap is flat or on slope? will it cause leak once flat? The attached is the flat roof flashing/slope transition. I do not like the work but seems that is the way.

I believe most flat roofing in BC are motified Bitumen. Theoretically it should last over 20 yrs but normally only about 10 yrs. In this case, no much difference from Roll roofing. Any thoughts?

[John Svoboda]

Yes- this is just the sort of solution I had imagined as being correct. Thank you sir!
John

Here is how my roof with EPDM has been done at the eaves and something similar should have been installed as per your concerns. 29430

[John Svoboda]

I'm no EPDM expert but I have been around construction most of my life. I don't think those fasteners showing through are a problem now or likely very soon. The intensity of our sun here at 5k foot elevation may play a role. They all show pretty equally so foot traffic is likely not related. But when the membrane does fail I bet those are the spots.


Fwiw, Any EPDM systems I have seen have had the ghosting of the fastener making it noticeable. My own roof is the same.

UltraFast Fasteners and Plates - Roofing Materials | JM (http://www.specjm.com/products/roofing/ultrafastfasteners.asp?system=epdmsingle&type=fully)