Renewing a Flat Roof

Cordie

Anyone here with recent experience of having a flat roof renewed, mine was done about 30 years ago and there appears to be more options available now.

My flat roof is attached to the side of the house, it is not a lived-in space but a passageway and old coal shed. It is also attached to the neighbours coal shed and in full sun for much of the day if that makes any difference to the type of surface that would be available to use.

Any opinions would be appreciated.

smudger1964

I have used this https://www.rubber4roofs.co.uk/classicbond?&mkwid=sa0R76jBp_dc|pcrid|107707137038|pkw|epdm roofing|pmt|e&mh_
on my flat roof its a fit and forget kind of thing its a little more expensive than felt but you never need to do it again
I have done it on my rear flat roof extension in full sun most of the day

I have also fitted it to my large shed roof 4 years or so ago easy to fit too

babyblooz

Smudger 1964

We are wanting to renew our existing flat roof which is an extension to the main part of the house and where we have our dining room. There is no insulation in it at all and it is always cold at that end of the house. Even with heating on it still seems cold so we thought if we renewed it and added insulation then this might have an effect. I've read up a bit on it and a 'warm roof' seems to be the way to go but then we have different options of what to put on the top surface. We have thought about the rubber option and the fiberglass. We need to be able to walk on it because we have a bedroom window overlooking it.

Did you have any insulation put it when you had your roof done and if you did has it made the room below any warmer? We have south facing patio doors in our extension so hopefully we would be able to get some free heat and then hang on to it if the insulation does it's job.

Any advice would be appreciated.

smudger1964

I havent had any experience of a warm roof but im sure someone will come along soon who has
https://www.rubber4roofs.co.uk/epdm-warm-deck-roof-design
this is the section on warm roofs..I inserted some fibre glass insulation in the gap between the ceiling and the roof in my extension..It has made it warmer in mine as there was none there previously
My flat roof extension is only some 4meters by 3 meters and used as a laundry room come dumping ground and not lived in as such

nickcc

I had both my extensions covered using EPDM Firestone roofing and supplied by Permaroof. It's supposed to be suitable for DIY use but if not applied correctly you end up with large air bubbles. I'd certainly use the product again but not let my dodgy builder lay it for me.

babyblooz

I'm glad its made it warmer. That's what we are looking for but having read about it, it would seem that putting insulation in between the joists over time can cause damp and then trouble with wood rotting, unless you have ventilation at both ends to allow condensation to disperse.

If I understand it right the idea of the warm roof is to leave that gap between the joists free of insulation and then above that apply a vapour barrier followed by sheet insulation such as king span etc, then your finishing layer, either rubber or traditional felt etc. If you need to walk on the finished roof then you'd need to board over the insulation to make it strong enough to bear weight.

I am getting very confused as this seems to be the preferred option yet the photo's that roofers are using on their websites or facebook pages don't seem to be using that method.



That's why I am interested in other people's experience and opinions.

This is the link I have been watching. https://www.youtube.com/watch?v=wyNviteSOzY

nickcc

Our flat roof is packed with insulation between all the joists with plaster board skimmed as the finish. This met with local building regs, we still get plenty of condensation but have a de humidifier running for 4 hours per day, we live in Cornwall.

ColinFishwick

I have both fibre glass flat roof and several EPDM roofs. Porch, bay, small extension and two garages. Fibre glass is better but EPDM come a close 2nd and can be done yourself if your competent. I even put EPDM on my shed as 2 year old bitumen roof which came with the shed was pants and I got a decent shed tongue and groove

babyblooz

Any ideas on how much I should be looking to pay for the rubber option? Our roof is about 3.5m x 3.5m.

phil24_7

babyblooz wrote: »

Smudger 1964

We are wanting to renew our existing flat roof which is an extension to the main part of the house and where we have our dining room. There is no insulation in it at all and it is always cold at that end of the house. Even with heating on it still seems cold so we thought if we renewed it and added insulation then this might have an effect. I've read up a bit on it and a 'warm roof' seems to be the way to go but then we have different options of what to put on the top surface. We have thought about the rubber option and the fiberglass. We need to be able to walk on it because we have a bedroom window overlooking it.

Did you have any insulation put it when you had your roof done and if you did has it made the room below any warmer? We have south facing patio doors in our extension so hopefully we would be able to get some free heat and then hang on to it if the insulation does it's job.

Any advice would be appreciated.

I have a warm roof (18mm OSB board/100mm PIR borad/18mm T&G OSB)on my garage which also has 50mm PIR board in the cavity and an insulated garage door. It is toasty in there most of the year around (2 large double glazed windows in the rear projection facing East and South) and is warmer than the actual house!

I have fibreglass on it and having the extra layer of OSB on top means there is no danger of damaging the roof from walking on it. The only danger would be from dropping something on it.

phil24_7

babyblooz wrote: »

I'm glad its made it warmer. That's what we are looking for but having read about it, it would seem that putting insulation in between the joists over time can cause damp and then trouble with wood rotting, unless you have ventilation at both ends to allow condensation to disperse.

If I understand it right the idea of the warm roof is to leave that gap between the joists free of insulation and then above that apply a vapour barrier followed by sheet insulation such as king span etc, then your finishing layer, either rubber or traditional felt etc. If you need to walk on the finished roof then you'd need to board over the insulation to make it strong enough to bear weight.

I am getting very confused as this seems to be the preferred option yet the photo's that roofers are using on their websites or facebook pages don't seem to be using that method.



That's why I am interested in other people's experience and opinions.

This is the link I have been watching. https://www.youtube.com/watch?v=wyNviteSOzY

For occasional foot traffic you can get away without boarding over the top (you do run the risk of denting the insulation depending on the finished surface though), you can also get away without boarding underneath (though 1 side needs to be boarded) as the weight is transferred over several joists.