EPDM fastners concerns

Hi folks,
I am wondering how concerning the “protusion” of the fastners below the rubber is. To me it looks like a potential concern for poking through the rubber in the near future. I would think as the roof is exposed to the sun, the material is going to become more brittle and have a greater risk of the fastners poking through. I admittedly do not see a lot of EPDM roofs, at least with this concern.
The owner does not know exact age, but was told it is relatively new.

Looks like a big patch job.
The roof does not look like the contractor installed the EPDM membrane professionally as required by the manufacturer, installed on a nice clean flat roof deck surface.
The surface of the EPDM appears bumpy as if a BUR gravel roof was not scrapped clean and flush to the membrane ply’s and covered with a thin sheet of iso board and fastened with those buttons retainers.
The orientation looks wrong. Water will flow into seams
As well shrinkage. The membrane pulled away from the flashing.
There are small air blisters near the seam.
Refer your clients to a licensed roofing contractor for further review and maintenance prior purchase.
Lets hear what others have to say. Mr. Cyr is good with EPDM.

  1. General Exclusions.
    (a) Home inspectors are not required to report on:
  1. Life expectancy of any component or system;

(b) Home inspectors are not required to:

2. Calculate the strength, adequacy, or efficiency of any system or component;

8. Predict future condition, including but not limited to failure of components

It is functioning as intended, till it no longer is…

There is nothing posted that indicated the roof is damaged or not functioning as intended.

(iii) State any systems or components so inspected that do not function as
intended, allowing for normal wear and tear, or adversely affect the
habitability of the dwelling

It goes on to say you can report items not listed in the Rule.
But if your inclined to, you are on your own. You can’t come back and claim it’s not a Home Inspection requirement.

This is typical of EPDM roof, the mechanical fasteners are used to attach insulation or such and then EPDM goes over that. The fasteners telegraph through and normally cause no problem.


Robert- I see nothing there to support your claims.
Looks as professional as it gets for a residential job.
Seams are chemically welded, it’s not asphalt shingles that lap each other. I don’t see a leak. The roof is low pitched. No indication of standing water locations.
The membrane is not pulling away. It is also welded to the flashing.
Air blisters? In the weld? Does not cross the weld.

Sorry, I see no reason to make an issue about any of this. These roof have up to a 30-50yr warranty (but not on residential applications), that’s 3-5 times the rest of the roof.

Marcel, myself and ten others from here attended the Firestone Training Center with a bunch of architects. All I do these days is diagnose Thermal Imaging roof scans for drone pilots. I wish half the roofs I work on were this good.

I see what your calling out, but I can not see a further investigation on what your looking at without more associated issues which the OP did not include.


David, what do you think about that one photo of the one uplifted fastener? Do you think it may rupture the membrane or should be corrected?

Afternoon, David.
You have the right. I was awaiting others to chime in.

Here is a zoomed in illustration of the right corner.
epdm roof illustration 1

How do you propose to correct it? Would trying to correct it cause more damage? At this point it does not appear to be failing, why promote it? It is a potential source of failure, however nobody walks around on this roof like they do on a commercial building. Again, are we not speculating on failure?

1 Like

Well yeah, you would have to cut it then patch it. I guess it depends on the severity of the issue or how widespread. I’m not a big fan of cutting a membrane that is not leaking :smile:

@acotton21 this may be helpful

Blisters are not a concern as long as they don’t exceed the manufacturer’s standard, usually 25-40% maximum of the area of the seam. I locked horns with Firestone over this about 8 years ago, and couldn’t prove them wrong. I even had two samples tested by a lab. Also, blisters are not a defect stemming from any sort of mechanical stress. They stem from too short of a curing time time of the contact cement. If you don’t wait long enough for curing, once you make the seam, the adhesive will off-gas vapor and create the bubbles within the first 24 hours or so.

What I see from the photo is insulation anchors translating through the membrane (normal), and seam tape covering the edge flashing (normal, as long as the main membrane hangs over the edge of the roof). The edge caulking is also normal.

What I don’t like are the flashing fasteners driven through the main membrane along the edge, and the width of edge flashing flanges. That’s no bueno in my book, but then again it could be some manufacturer’s standard detail. But I doubt that.

Thank you to everyone who responded. This was very helpful. I see the concerns Robert had pointed out about the blistering and seam orientation. I also agree with David in trying to find the severity of the issue. I also agree that it appears the roof is doing its job correctly and no need to make a big fuss or have someone tear into the roof if not necessary. This is a post-sale inspection and they already own the issues. I wanted to double check as I am not too familiar with seeing so many fastners telegraphing through. There are seams (which I did not include photos of) that are degrading and starting to crack, which will require to repaired shortly by a qualified roofing contractor anyway. This was more for my own learning experience.
Thanks again


Where do you see this?

Great info, thanks.

Some of those fastners appear to be gasketed roofing screws.

This appears to be the detail they used for the edge along the lower portion of the photo. I don’t agree with driving fasteners through the primary membrane.

Likewise this is Firestone’s gutter edge detail.

Good to know. Thank you, Darren.

Darren, does the roof flashing in the OP’s post look anything like the flashing in the Firestone flashing illustration. You made my point. The seam is downhill with the membrane inches away. As well I think there is another roof underneath. The perimeter looks like an older EPDM membrane. Why would you strip roughly 1’ foot with epdm and then put the membrane. That is why the used an insulation sheet.

That weld is 6" wide. The edge matters not.

Agreed, however from HI perspective it is working (and for a long time). The job as Home Inspector is to detect defect, not analyze installation technique that is working. If it is determined to be failing through IR or other testing, the way it is installed can explained the leakage etc. However that is not in the HI preview either.

(6) General Exclusions.
(a) Home inspectors are not required to report on:

  1. Life expectancy of any component or system;
    2. The cause(s) of the need for a repair

Improper install could void warranty, but last I heard there is no warranty on residential applications like this anyway. :thinking:

Thanks for the input Darren.