EDPM roofing

[djs63]

Hi, does anyone have experience with EDPM roof material please? To go on garden office, thinking particularly of bits falling off neighbouring trees trying to puncture it!

[kdmnx]

I have no direct experience. However I looked into it when building my garden office a few years back:

- EDPM is a high end roofing material with a 50+ year lifespan.
- Fitting it correctly is a skilled job. Doing it yourself is probably a false economy.
- Ordinary roofing felt is way cheaper, you can install it yourself and it lasts 20 years (if you buy the good stuff).
- How long do you expect the rest of the structure to last?
- Both materials will cope with twigs/leaves and both will fail if a large enough branch falls.

As you can probably guess I went with felt. If I was re-roofing a dorma or other flat-roof structure of my actual house I'd pay professionals to install EDPM.

[billi]

Hello ,

I did  a green roof (30% slope) on my logcabin (100m2) with an Epdm , and  planted it , the membrane itself should last decades if covered

Tricky part is the connection to roof-windows  and rainwater run of connections , but there are  proper designed ideas for those "problemzones"

Billi

[Countrypaul]

When we renovated our current house, we have 3 largish flat roofs to cover and 5 small ones, all were done with EDPM.  One large one is 2m x 9m with a parapet wall on 3 sides and a sloping roof joining it on the 4th with 2 outlets through the parapet wall opposite the sloping roof (long side), another large one is on a sun room 3m x 4m with one side a wall and the other 3 side have a 45 degree slope for about 18" followed by a 1 foot verticle drop to to the gutter with the EPDm then tucked underneath and a drip strip attached to ensure a clean break. The final large on is on a dormer and is 2.5m x 9m with sloping roof above one long side and at both ends, the other long side has two sections that are 18" wide and 18" back from the edge (thanks to local planners!) with guttering along the 3 sections of full width. One small one is on a dormer 2m x 2m otherwise much the same as the larger dormer, the other small ones are over a triangular bay and other triangular windows.

The parapet wall roof and dormer roofs are all 175mm SIPS which required covering with 12mm plywood prior to the EPDM so as to have something decent to glue down to (OSB not acceptable), the sun room has 9mm ply over 200mm of PIR (long screws to hold the plywood down). This roof also has 33 outriggers for a brise soliel (?) with come out through the PIR and EPDM. The final ones are all over wooden structures with 200mm XPS insulation and plywood covering.

The roofs have only been in about 5 years (3 for the sun room) and have had no problems even though we have many trees about and lots of twigs hit the roofs. One feature of EDPM is that it is easy to apply patches if it does get punctured for any reason (it our case someone managed to nail a lat the wrong place so we have 3 or  small patches on a sloping section hidden beneath tiles now - there was a debate about whether it was necessary to path given the location but decided it was safer to do so even though it wouldn't be seen.

The only problem we have is some areas of EDPM have lifted from the plywood - think this is because it was applied during autumn and when the sun has hit it in summer moisture has come out and lifted small areas. We have not done anything about it.

We had a look at alternate solutions for the sun room but due to the difficulty in fitting other solutions (felt and fibreglass) EPDM seemed to be by far and away the best (and also matched the other roofs.

You can buy DIY kits, and having seen the roofs fitted, I would certainly be tempted to DIY if it was a smaller straightforward roof  - say upto 4m x 4m. The EPDM comes as a single piece and can get very heavy, even at 4m x 4m getting in onto the roof is likely to require move than one person.

[biff]

I was never a fan of flat roofs,
          However any time I uses Esso Butyl, I was more than happy with the results, So were my customers. I used the trim and edging provided, The upstand can be problematic   and need full support under the angles. I cut the flashing groove to the main building with a con saw on the rail,  Then used a 225 lead apron  down the upstand and  onto the roof. The lead over the sheet was trapped with lead plugs and rendered into place 50mm below the flashing groove. Securing the batons to plaster to is tricky because you must not puncture the sheet or flashing so the edging batton is suspended from the wall,above the flashing. I screwed lengths of 50 x 25mm x 900m every linear 600mm,  they have to be secure and the whole outfit is best assembled on the ground then taken up and banged into place to a line with good quality masonry nails. This is quite a tricky job and you need an extra pair of hands.
  Once the flashing has been rendered into place and the bellcast setting, you can get on with the rest of the job .
   It seemed to me back then  that most cases involving esso butyl roofs were emergencies and improvisation  was a key word. The flat roofs were carefully checked for sharp projections, In two cases, We did not stick the sheet
  Instead we rolled it out and secured it with the edging which was raised 50mm above the rest of the roof. Then we laid sheets of 50mm poly and threw buckets of round shore pebbles over them, the sheets stopped 300mm from the edging and the whole roof was covered in 50mm poly with a 50mm layer of pebbles on top. A few times when the wind was hammering the building like it is hammering  our house, right this minute, the whole performance was like a reality TV show with bits of poly and pebbles taking off into the beyond. Yet sitting inside afterwards over a mug of tea,  we had to admit that the Esso Butyl  the poly and the pebbles were a rather good job.
    Give me a good peaked roof any day.
         Biff
  

  

[desperate]

The trick with rubber roofs is to get a flawless contact between the rubber and decking sheets, it sounds straight forward but unless your roof is all on one plane it really isn't. I've seen a fair few of them that look pretty flaky to be honest, I don't believe 50 years either. Like a lot of these things if it is put down  professionally it will be OK.

Desp