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weetoo 04-12-2008 02:19 PM

leaking flat roof
2 Attachment(s)
I have a flat rubber roof with a slight pitch.that has developed a couple of leaks. I tried to coat with tar but that has not helped . If anyone can give me any suggestions it would be greatly appreciated. thanks

johnk 04-12-2008 03:07 PM

Shouldn't have used tar that's for sure.Tar eats rubber.Time to re-roof:no:

tinner666 04-12-2008 06:01 PM

I think Ultra19 is compatable with APP, but it's not really a fix. You might have just signed a death warrant on that roof.

weetoo 04-12-2008 06:20 PM

leaking flat roof
thank you for info. so now do I just strip the rubber off and can I use roll roofing or do I need to replace with a new rubber roof. thank you

johnk 04-12-2008 06:28 PM

There are many flat roofing solutions out there.No,you don't have to use rubber.Most are not for the diyer though.Best thing to do would be to get a few quotes from reputable roofing companies and decide from there.

weetoo 04-12-2008 07:33 PM

thank you for the help .

Ed the Roofer 04-13-2008 12:51 PM

I just want to make sure of something.

From the photo of the flat roof, there seems to be too many seams for most actual Ruuber Roof systems and I can not tell from the picture for certain if it truly is an EPDM Rubber roof or if it a Modified Bitumen Torch down roof material.

Either way, regular plastic roofing cement is not supposed to be used.

The reasoning is, that the roofing cement, to remail pliable for usage, contains certain Solvents, which can attack and leach into either one of those membranes.

Note: This next statement is only my opinion.
An exterior application of roofing cement "Should" allow the Solvents to "Flash" out of the product into the environment, rather than directly into either membrane.

The problem with using plastic roofing cement, especialy on an EPDM Rubber roof membrane, is that the membrane expands and contracts substantially and that the roofing cement becomes dry and brittle. especially when exposed to the drying out process from the ultra-violet rays of the sun.

Once it becomes hardened and brittle. it wil beging to further pull the seams apart, causing additional seam leakage, because it was applied without any reinforcement mesh.

Is the material as thin as a bicycle innertube or is it thick and rigid?

I would like to see some close up shots of what you perceived to be the leak sources and of the wall flashing termination and where it ties into the shingle roof, especially in that corner area behind the wal.


johnk 04-13-2008 01:05 PM

Well put Ed,but either way he went pretty hard on the plastic cement.Wouldn't you say it's unrepairable?

johnk 04-13-2008 01:07 PM

Even if it was modified bitumen,you should always use compatible products.

Ed the Roofer 04-13-2008 01:12 PM

It really depends on what was causing the leaks in the first place.

If it is EPDM, and the seams were fismouthing, meaning opening up and allowing water to enter through them, then he eliminated the proper contact surface required to adhere a patch to by contaminating the seams.

If it is a Modified Bitumen roof material, even though he wil have to wait for the roof cement to harden enough to scrape it off and wash it out of the seams with a soplvent, it "May" and I only suspect less than a 50% chancxe of this, be able to be reheated with a small torch to adhere the seams once again.

The pictures will really help for an accurate assessment though.


weetoo 04-13-2008 06:00 PM

5 Attachment(s)
I would say the membrane is ridged it is about the thickness of a quarter. I tried to take enough show what the roof is like . The tar is still not set up and I could scrape some of it off. should I do that or what?I hope I got the pics you wanted. thanks again for any help.

the roofing god 04-13-2008 07:54 PM

YOU HAVE A SMOOTH SURFACED RUBBERIZED BITUMEN ROOF,not epdm,if using tar use karnak ultra,or tamko rubberized SBS cement,embed fiberglass membrane (4")so 1/2 is on each side of the seam,and then recoat it again this is called 3 coursing or stripping in and is not a problem,check the entire roof for holes or tears in the roof membrane,and treat them the same way,ultra membrane,ultra again----if roof 3was very dirty,yopu may want to scrape the plastic cement off,and brush coat the seams with asphalt primer-then do all your 3-coursing with the ultra,and membrane,then as a final touch,mix up a can(5 gal)of fibered aluminum roof coating,when you do this mix it quite a bit till the coating is silver color and all the fiber from the bottom of the can is thoroughly mixed in,then using a paint roller,brush the coating up against the seams,leaving it heavy at the seam area,and make a point to only roll one way not back and forth,after all the seams are laid up with the coating roll it over the rest of the roof,make it a point to apply it heavily--this should have been done shortly after the roof was finished for proper protection---now by your pictures,with the seams sealed you are still leaking??--this may mean that the leaks are coming from the shingle area,running down under the undelayment,and the roofing itself,check the shingles thoroughly,including any flashings and vents,if possible take more pics of the shingle areas above the flat roof area,and post them here so we can examine them,and see if anything stands out----although the rubberized bitumen roof area should have been aluminum coated,with the seams sealed,and the roof still showing leakage,I`m inclined to believe you have leakage thru the shingle areas,not the flat---the rubberized bitumen also probably does not need replacing either!!

tinner666 04-13-2008 09:23 PM

Can you figure out, inside the house, where the leak(s) showing up, from above? You know; X marks the spot that the leak is directly below?

And give us more detailed pics of that?

weetoo 04-15-2008 06:10 PM

6 Attachment(s)
I tried scraping the tar off which is not working well and marked the areas above where the leaks are with chalk. the u shape valley I cleaned tar off of and there is a slit i hope you can see it where the rubber material steps down to the flat roof. that i,m sure that needs to be sealed.just want to make sure i understand what you stated .I should be able to use the 3 step repair over the tar and it shouldn't hurt to seal that in? thanks

Ed the Roofer 04-15-2008 07:04 PM

Read post #'s 5, 7 and 9 out of this thread.

It describes in descriptive detail the process to patch seams with an MB Cement, with a link to one version of the product.


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