Flat Roof Refurbishment

[Creakyoldhouse]

Hello,

 

I have two GRP flat roofs that are failing due to poor installation and need to be replaced, including the build up. They are each about 25m2 and have a large roof lantern in the middle. The lanterns are wood and a pain to remove (impossible without damage). I am concerned about using GRP again given our bad experience so I want to look at other options too, such as EDPM. Would it be impossible to re-roof in EDPM without removing the lanterns? They sit on an upstand so it wouldn't be possible to bring the EDPM up over the top with the lanterns still in place. Any thoughts welcome please.

 

Thanks

[scottishjohn]

as you stated the problem with the GRP was installation --not the product itself

 with grp roofing it is essential that the boards under them are replaced at same time 

 

 If these roofs were a repair of exsisting other roof 

my guess is they cut corners 

the prodcut is fine 

 

 as for a rubber roof 

i have a friend who has a hotel with rubber roofing ,or had 

the crows would take things up on there and peck at them  and made holes  in the membrane 

 it could also be they did not allow for expansion 

a good roofer will know how big it can be before it needs expansion flashings

 note the expansion joint on my balcony 

and lead flashings in the stone work that come down over the grp upstand flashings at the edges

Edited October 16 by scottishjohn

[Creakyoldhouse]

That’s interesting. Thanks for sharing your experience. I think I will speak to some local GRP installers to see what is possible. 

[Conor]

show us some photos. I've installed two DIY GRP roofs and I've never had an issue. Might be able to sand it down and put another layer on.

[Creakyoldhouse]

Hi Conor, I can’t show photos right now but the GRP is flaking and large cracks have appeared over board joins. The roofs are very noisy in the sun and make loud banging noises when temps drop at night. No firrings were used at joist level and the roofs have standing water all the time so need a proper fall and we have no height available to work on top. 

[scottishjohn]

16 minutes ago, Creakyoldhouse said:

Hi Conor, I can’t show photos right now but the GRP is flaking and large cracks have appeared over board joins. The roofs are very noisy in the sun and make loud banging noises when temps drop at night. No firrings were used at joist level and the roofs have standing water all the time so need a proper fall and we have no height available to work on top. 

sounds like rip it all off and start again

I there  somewhere the water goes off the roof into a drain pipe  even if its flat ?

 if its not a roof you ever walk on every day  and its very flat you could cover it with a layer of chips when its done .that will keep water on tthere  to ceratin level and stop it getting too hot

[Creakyoldhouse]

Thanks Scottish John. There is a drainage outlet but the fall is rubbish so water doesn't exit unless at a very high level. The roof is only walked on for maintenance so I will look into adding a layer of chips, thanks!

[scottishjohn]

1 minute ago, Creakyoldhouse said:

Thanks Scottish John. There is a drainage outlet but the fall is rubbish so water doesn't exit unless at a very high level. The roof is only walked on for maintenance so I will look into adding a layer of chips, thanks!

it was very common when everyone used roofing felt as summer temps would cause damage

Edited October 17 by scottishjohn