How to improve edge of rubber membrane over gutter?

[David001]

A roofer has fitted new outward-slanting roofs on two dormers here which had always had inward-slanting roofs.  The aim of the new outward-slanting roofs was to ensure that falling leaves will no longer settle and clog at the back of the dormers, stopping rainwater from escaping from both roofs, causing trapped water to freeze in water to damage the surface of the dormers, with rain-water then leaking into the rooms below.

 

So the new roofs have achieved the objective except that it seems to me that the roofer cut the EDPM (rubber membrane) a bit short on both new roofs and this could cause problems in the future.  I think the roofer should have let the EDPM run over and into the gutter.

 

It seems to me that having cut the EDPM too short, the roofer then tried to remedy the fault by inserting a plastic tray behind the edge of the EDPM.  The plastic tray hangs over the gutter.

 

In the photos below you can see that the edge of the EDPM is somewhat wavy, and that there are occasional air-spaces or gaps between it and the plastic tray running behind it. 

 

The dormers are north-facing, and I know only too well how easily moss develops in wet crevices on the north-facing side of this house!  So I expect that moss will develop in the spaces between the EDPM and the plastic tray, that the moss will eventually press its way further into those spaces so that it reaches the edge of the plastic tray and the surface of the OSB board lying under the EDPM - at which point the OSB will begin to absorb moisture.

 

So what can I do to improve the two edges myself?   

 

 

Photo 1, below: the old dormer roofs, slanting inwards, taking leaves and rain-water towards the centre of the house, for the rainwater to find its way past a mess of clogged leaves so as to escape around the four corners and then flow down eleven slates to the gutters at the bottom of the slates.

 

 

 

Photo 2, below: the new dormer roofs, sloping downwards and towards their own gutters, the rainwater then emptying through downpipes on the left side of each dormer (not visible in this photo).  Note the visible edge of the EDPM adjacent to each of the two new gutters.

 

 

 

 

Photo 3, below: the left end of one of the two new gutters.  See the plastic tray, meant to take all rain-water from the EDPM above it.

 

 

 

 

Photo 4, below: a close-up shot showing the wavy edge of the EDPM, with the plastic tray under it, the new gutter below.  I think the EDPM needs to be permanently adhered to the tray, with no gaps between the EDPM and the tray.

 

 

Thank you for your help.

 

David.

 

 

 

 

 

[Alan Ambrose]

Think I agree. Pity otherwise it doesn't look a bad job. The epdm is stuck onto a board below?

[David001]

@Alan Ambrose, yes, I think is glued to the OSB board.

[kandgmitchell]

That gutter edge is surely wrong? It depends on the individual system but some have a two piece trim that sandwiches the membrane. If I recall the system we used a few years ago on a porch roof had a mechanically fixed gutter edge membrane strip that the main sheet glued onto using contact adhesive. Whatever it should be it ought to be neater. Best way is to find out who makes the edpm and look up their standard installation detail on the web. That should illustrate how it's done.

[Alan Ambrose]

My epdm shed roof was supplied with a pva-looking glue to hold the majority of it down and a contact-adhesive looking glue for the edges.

 

I guess sticking the free edge down with contact adhesive would be a good start.

 

But epdm isn't very expensive, so it wouldn't be a big deal to replace it with a bit the right size.

[Russdl]

There is a specific gutter trim that should have been used, Google EPDM gutter trim and you’ll find it straight away. I think it needs ripping off and doing again as has been suggested, it wouldn’t take long or cost the original installer a great deal. 

[David001]

@Russdl, thank you!  I have googled as you suggested and indeed found that there are such things as "gutter trims".  I will get in touch with two companies offering an EDPM roofing system and ask their advice.

[David001]

Update, @Russdl, one supplier of an EDPM roofing system has responded by sending me a PDF of instructions as to how to use their system, and it seems to suggest that when it comes to the gutter edge, using their system first of all you screw in a long plastic plate along the vertical edge, and then you attach another long plastic plate by pressing and clipping it on top of the first one.

 

Have I interpreted the directions correctly?  Is that how the gutter edge should be treated?

[Russdl]

@David001 there are several slightly different solutions out there. Here’s an installation video of what I installed, which sounds similar to what you are describing. If it is, then looking at the pictures you posted I don’t think you have enough EPDM to lap over the gutter trim.

[David001]

@Russdl, thank you very much for that very clear installation video of the EDPM which you installed.  I have invited the contractor to consider the situation and I look forward to his response. 

 

This has been a very trying experience.  Initially the contractor delegated the work to a rather wild young lad who clad the dormers as below.  The first shot shows how the cladding did not follow the original horizontal lines of the slates, and that when he fitted the guttering he aligned it with the slanting cladding, so that the gutter rose up towards the downpipe and so the gutter remained half full of rainwater.  The second shot shows how the four corners, on the two gutter edges, were "finished".  

 

After I brought these issues to the contractor's attention he and a different assistant came and spent an additional four days rectifying the earlier work - and at some point they trimmed the EDPM right back to the edge of the roof.

 

 

 

 

[Russdl]

Good grief. 

[David001]

@Russdl, thanks for that confirmation of the shoddiness of the work done. 

 

As the contractor has been paid, and as he has already spent an extra four days here rectifying most of the mistakes of his assistant, I don't expect to hear from him.  So I have wondered how I can "make good". 

 

I am thinking along the lines of cutting two fairly heavy planks to the widths of the dormers and then screwing a wooden baton along one edge, to create a solid L-shape.  Then I am thinking of injecting some "Roof and Gutter Sealant" all the way along the underside edges of the EDPM, or at least in those spaces where the EDPM is not glued securely to the strip of plastic which the contractor placed behind the rubber.  And then I would carefully lay the L-shape along the edge of the dormer with the baton pressing against the vertical edge.  I am hoping that after 24 hours I could then lift off the planks, leaving the EDPM permanently fixed to the plastic strips.

 

I have some "Soudal Roof and Gutter Sealant", which is described as:  A rubberised, oil based sealant that remains semi flexible after curing.  Ideal for applications such as guttering, downpipes, lap joints, chimney stacks and flashings.  Excellent adhesion to common roofing materials such as asphalt, bitumen, felt, metals and wood.

 

Will such a "Roof and Gutter Sealant" act as an adhesive on rubber?  Will it bond to rubber?

If not, could you recommend another product which I could use in the same way, to fix the EDPM to the plastic which has been laid behind it?

 

Thank you.

[Russdl]

@David001  I’m no expert, I’ve laid EPDM once but I don’t think your solution will last, mainly down to the detail Ive highlighted in your picture below. 
 

 

I don’t think you’d get an effective or long lasting seal on those corners and the roof will fail in the not too distant future. If it were me I’d do exactly what you are doing, namely asking on here, and if that failed I’d be looking at a minimum of bonding a strip of EPDM to the underside of that which is already in place and then have the correct gutter detail installed correctly, with the correct amount of EPDM in that gutter trim.  Your ‘upstand to gutter’ detail could still be problematic.
 

Ideally rip it off and start again but I can understand the reluctance to do that. 
 

Someone with more knowledge and experience with EPDM will perhaps be along soon to give you an alternative viewpoint and/or solution. 
 

Alternatively, ask an EPDM supplier what they recommend as a solution, the video link I posted came from a company that were very helpful when I asked questions. 

[David001]

Thanks, @Russdl.  

 

The latest is that the contractor has said that:

 

1. They prefer not to use a gutter trim because it fades to a grayish white and eventually splits (in which case surely the side trims and the side cladding which they fitted would also fade to a grayish white and split).

 

2.  They have ordered some hot-glue and will come and bond the EDPM to the grey plastic tray which they placed behind it. 

 

So I will see what improvement the hot glue makes.  The last time I saw hot-glue being used to bond a felt roof onto an extension, a long and powerful blower-torch was being used.  If they use the same kind of torch here the plastic and the gutter will melt.

 

Thanks for your help and advice.  It's really appreciated.  I will update the thread once the hot-glue solution has been tried.

 

 

[FuerteStu]

 Just my 2p worth. 

If it looks that bad from what you can see, it will be worse that's covered up. 

 

Think of the over all cost of repairing a lot more than just the trim of the epdm. 

 

Contact the guy (he's not a tradesman he's a chancer) and tell him your second opinion has confirmed the work is substandard, and that it he isn't willing to refund you the labour costs, then you'll consider legal action to recover the entirety plus costs of putting it right. 

 

You will have countless sleepless nights every time it rains hard, the wind blows strong, or there is snowfall sitting on it. No amount of cost would offset that. 

 

Get someone in to do a proper job.

You'll be glad you did

 

 

[Russdl]

2 hours ago, FuerteStu said:

If it looks that bad from what you can see, it will be worse that's covered up. 

That’s probably spot on @David001, have you got any photos of the substructure?

 

Get some money back money off the original installer (if you can) and then don’t invite the back, take your time to find someone who can do a professional job (what you’ve got should be ok for a few months) and get it redone properly. 
 

4 hours ago, David001 said:

They prefer not to use a gutter trim because it fades to a grayish white and eventually splits

Sounds like a complete load of bollox but even if it was the case it would just be the front part of the trim that would need replacing which is pennies in the grand scheme of things. 

[Alan Ambrose]

Just leaving the epdm longer so water flows directly into the gutter would have been a good start.

[David001]

Update: the contractor has screwed a long plastic baton to the edge of the top surface of the dormer's edge, to keep the rubber sheet down.  They placed spacers between the rubber and the baton, so that rain-water will be able to pass under the baton and then down into the gutter.  They did not consider that the gaps between the rubber and the baton will eventually fill with debris gunge, and moss, and that the baton will cause leaves to pile up against its higher side.  

[Russdl]

It seems like what your saying is that he’s penetrated the membrane at several points and installed spacers to ensure debris and water is trapped at those points of penetration in order to guarantee that the roof fails sooner rather than later.

 

Is that about right? 

[David001]

He's separated the baton from the rubber by placing 4 or 5 little piles of spacers (set at intervals) underneath the baton, then he has fixed all in place by driving a screw through the baton and the spacers beneath it, then through the rubber, and into the wood baton under the rubber.  

 

I think he's added the baton as a way of hiding, masking, or disguising the little piles of spacers. 

 

I think his intention was to hold the rubber firmly down at 5 or 6 points along the top edge of the dormer.  I think his first thought may have been to screw a baton directly along the top of the rubber, but then he realised that the baton would be an obstruction to water and debris.  So then I think he decided to raise the baton above the rubber by a centimetre or so, by way of using the little piles of spacers.

 

Every year now I will need to get up there with a thin screwdriver and make sure that the open areas between the little piles of spacers (under the baton) are free of debris, moss, etc.

 

 

[FuerteStu]

So he's basically gone against all standard practices, the manufacturers recommendations and all logic.. Rather than do it properly

 

Don't allow him near your house again. 

 

When it fails, which it will.. Get a proper tradesman in. 

[David001]

@FuerteStu, indeed!  Never again near this house. 

I am now very glad that I insisted that the old fibreglass roof coverings were well-coated with liquid rubber before the new roof was built on above it.  

 

I wonder if the current economic climate, in which many people can't afford to have work done, is causing some contractors to tell customers they are familiar with types of jobs with which they are actually unfamiliar and which they wouldn't ordinarily do.

 

[Marvin]

On 16/07/2024 at 16:34, Russdl said:

Good grief. 

Plus 1

 

Lots of videos available these days to show how systems work. Also parts can be seen at, for example, the Rubba seal website.

 

Good luck

 

Marvin