Does EPDM have to be glued down?

[SenileGit]

Hi, my neighbour has two smallish flat roofs on her front and back dormers that are covered with felt, and she says it's twenty years old and is afraid that it needs replacing. I am thinking of stripping the felt off and putting EPDM on - does this have to be glued down or can it just be laid on top as long as the edge trims are done correctly?
I only ask because I fitted EPDM on my 8' x 10' shed about five years ago by just screwing a long batten at either end of a large sheet of EPDM, rolled it up onto one of the battens, then unrolled it over the top of the shed (in the pouring rain, as the shed roof felt had started to disintegrate and I had to do it urgently), and then after it was unrolled over the entire roof of the shed, I just screwed the battens into the side of the bottom sides of the roof (sorry, I don't know the correct term), and refitted the flat timbers that go on either end of the roof (the two diagonals at the front and back of the shed, as it were), and I've never had a problem with it.
I only avoided using the glue because a) it was raining b) the roof didn't feel very strong and I didn't want to put my weight on it, and c) I'd watched a few videos of EPDM being put on shed roofs and they said that after putting the glue on the roof, you had to be very careful how you unrolled the EPDM onto it, because one mistake and it's stuck in the wrong place, so you could more easily get ripples in the EPDM.

 

[Notch7]

If you don't glue it, it will be ripple all over because it expands and contracts a great deal as weather changes.

That in itself doesn't mean it won't be waterproof - I put EPDM on a 20 square metre roof and left it unglued for a couple of months whilst work progressed and to allow the rubber to get some sun on it to relax out the creases.

Actually it's not true you can't reposition EPDM.

You lay the rubber on the roof, fold back one half, then roller on water based adhesive ( I vacuumed both roof and rubber, then glued both roof and rubber). You leave a margin all around.

Once the main bit is done you need to use solvent based impact adhesive....now that can't be repositioned.

It looks professional stuck down, stripping off the felt will be harder than gluing the rubber.

 

[^woody^]

Wind suction causing reverberation noise and stresses as it pulls the fabric comes to mind.

 

[SenileGit]

Thanks for the advice, I will use glue then, just wanted to make sure it was vital.

 

[andrew_ysk]

Isn't EPDM is the same material as pond lining ? So, we actually use pond plastic liner onto roof ?

 

[catlad]

Yes pretty much but the roofing stuff says not to be used for fish.

 

[^woody^]

A roof is no plaice for pond liner.

 

[andrew_ysk]

Haha! why not for fish ? if they are the same material.. should be same.. or maybe the roofing liner is of more toxic material.. we should use pond lining for water proofing instead.. less toxic.. (since fishes are not dead using it) lol

 

[andrew_ysk]

A roof is no plaice for pond liner.

If the roof is made with strength to withstand the weight of water.. roof is in fact the best place for a shallow fish pond, because the heat from house that escaped from insulation will goes to the pond water.. hence energy is put to good use.. lol..

 

[^woody^]

Plaice.

 

[andrew_ysk]

yup! good to do self sustainable ever since this kungflu happens

 

[SenileGit]

Last year I installed EPDM on a set of four sheds I have in my garden - I didn't use glue, I just used stainless steel screws and stainless steel penny washers around the edges. Initially there were a few wrinkles, because the EPDM had been folded up during delivery, but after a couple of months, it's as flat as a pancake. We also had terrible winds last year, and they had no effect whatsoever on the EPDM.
This is about 12 metres by 4 metres of EPDM, as the sheds are all joined together in a row. I'll have another look at it mid-Summer, to see if anything has happened to it in all the heat, but I expect it will be the same as it is now.

 

[datarebal]

Plaice.

A flat fish so shallow ponding will be ok

 

[robinbanks]

If there was a low spot that would cause ponding it would be better to fillet


Like Notch says don't worry about positioning it and gluing it at the same time-do it in half and it's very easy. Note that there may be a different glue for the edges than the middle.

Also another tip, there are a few companies that put their roll ends and off cuts on eBay at a lower price than full size sheets are; getting a smaller sheet may do well for your application

 

[SenileGit]

As I said, I didn't use glue and this is the third shed roof I've done (okay, this was four sheds in a row, so a giant roof), without glue, with no problems years later on the previous two.