What Kind Of Roof?

[securespark]

Hi guys.

Our flat roof is leaking. Knowing nothing about roofing, I'm not sure what is best to replace it with. I guess a pitched roof is best, but have not yet taken the plunge for a quote.

We have had a quote for a replacement flat roof using EPDM and 18mm marine ply, it comes in at £2500, plus insulation and any joist end repairs.

I'm guessing a pitched roof would be at least double this price.

We have also seen GRP roofs. The EPDM guy said they used to do these but moved over to the rubber after some "issues" with the GRP.


The roof is approx. 6.2m x 3.6m.

Could I trouble you for your thoughts, please?

 

[joe-90]

You may need permission to go to a pitched roof. Talk to your local Council.

 

[Zeberdee]

I'd get a few more quotes for the EPDM, £2500 seems a bit steep to be honest, Plus no need to use marine ply IMO.

 

[securespark]

Thanks for your comments.

Surely it's more robust?

How much would you expect to pay for this?

 

[masona]

There's no real answer to pitch verus flat roof. I would get a couple of quote for pitch roof then make up your own mind, have done mine few years ago but only cost me materials. I do think the pitch roof is more of advantage than a flat roof and depend how long you're staying there and if you don't mind paying the extra for a good long term investment or could be a strong selling point(?)
Pitch roof will give you storage space but if needed, you will need access via loft trap or which I have is a small door access though the wall and you can leave the old existing flat roof which will be the loft flooring area. A pitched roof is less maintenance, more pleasing to the eye and don't looks like a shoe box! A pitched roof is stronger, quiter in the rain and maybe a better heat loss and because of the shape they can withstand strong wind better than flat roof. I've nothing against flat roof providing it's done correctly and will say you will be hard to push it won't outlast the pitch roof. The problem I'm finding with flat roof is a very slow drainage meaning gutter problem such as grass/plant and debris which will need more clearing. Like I say you have to weigh up the cost with the pro and the con.

Also I would be a bit wary regarding some of these long term 40 yrs warranty of flat roofing materials but have a look at the stainless steel any others metal sheeting for flat roof which was mentioned here.

Normally you don't need planning permission, just building permission which is straight forward, ring your local BCO for their free advice

 

[securespark]

mason, thanks for your advice. Food for thought!

Cheers mate.

 

[DaveckJ]

mason, thanks for your advice. Food for thought!

Cheers mate.

£2500 is a bit steep for 23 square meters. As mentioned no need for marine ply. 18mm OSB is adequate plus has no structural voids in it.

Re-roof falls under building regs for thermal reasons - most people won't mention this to you. Insulation will probably work equally as well on pitched or flat roof - same R and U values.

Unsure how a pitched roof will be stronger than a flat roof or in what aspect? Pitched roof will be heavier for sure.

Personally have not yet heard of a 40 year guarantee though many EPDM fitters claim that EPDM has been proven to last in excess of 40 years - so do old fashioned plastic bags! (It was a piece of German research done on a sheet of EPDM rubber using a simulated aging process that produced this figure. Little peer review of the research and not much replication of the study. Research did not look at the glues used to hold rubber down or the uncured flashings or contact adhesives etc etc). That said the EPDM is not a bad material and is certainly better than felt.


Often the issues with GRP are due to the installer not being able to do basic arithmetic in order to mix components in the correct ratios. They then fail to consolidate it properly and run the air out. etc etc. Similar research to that quoted by EPDM installers has indicated there to be no reason for GRP not to last for the lifetime of a building if and this is the big IF - installed correctly.

I looked across at a GRP roof last week that was fitted in 1980 that still looked good and was as watertight as the day it was installed, which is more than can be said for the very silver coloured epdm roof I was replacing due to leaks (it was 8 years old by the way) owner didn't have much luck getting their guarantee honoured either

There are other alternatives out there also. Kemperol being 1 that is pretty damn good. But even for fitting that £2500 is dear!


HTH

DaveJ