Roofing Question

Flat roof, do i repair or replace? advice of materials and flat roof windows too

Flat roof requires maintenance for a small leak in the middle of ceiling. Should we replace the entire roof with new materials (9 years old) or just patch repair? If new roof, what material is best...felt, rubber, lead, fibreglass?
Also, considering a roof glass window to bring in more light on this roof. How do velux compare to other flat roof window providers? I have heard they can leak. Does anyone recommend the remote open close type? Don't want any leaks. Looking for self cleaning glass, not sure weither to go for a dome or a window for lots of light? Looking for quality not cost. Like doing things right first time, but useless with any type of knowledge n this area. Answers greatly appreciated...cheers

10 Answers

Best Answer

I would reccomended GRP Fibreglass as it’s a very robust product that comes with a 20 years guarantee from the manufacture. I have not ever had any issues with this product it has no seems / joins as it’s fitted and moulder tontge roof execelent product. The light issue realy depends on what u personly like I would advise you to go to a roofing supplies and have a look at the units most roofing suppliers stock samples the main thing you need to keep in mind is you need to employ a competent roofer you can rely on quality always comes at a price and if it sounds to good to be true genarly it is. Good luck

Answered 12th Dec 2017

Zenith Roofing and Building Ltd

Member since 28 Nov 2017


I would recommend getting a roofer to go up and check the condition of the roof before anything, it may well be a small dry lap or crack that could be repaired without too much cost or trouble, if however its discovered you do need a new roof I'd recommend either the GRP or a polyester based torch on felt if a new roof is required.. As per windows its down to personal preference, here's a link to roofing superstores flat roof windows to give you an idea of whats available

Hope this was of some help



Answered 24th Apr 2018

Reaction Roofing

Member since 9 Apr 2018

I would go for a new GRP warm roof to comply with current regulations. Guaranteed for 25 years with an anticipated life of 50 years plus.

I do not like Velux Windows. The upstands are expensive and made of plywood which are poorly insulated (12mm ply and 50mm of polystyrene). There are many good roof lights on the market with good insulation properties and ventilation (kitchens and bathrooms).

The good thing about fibreglass is that the detailing is second to none. Or you could insert sun tubes; we fitted four today on a warm sedum green roof they are excellent. All depends on your budget............


Drew @ Fibretechs Flat roofing - Glocuestershire & Herefordshire

Answered 15th Sep 2016


Member since 26 Jul 2012

I would personally go with epdm rubber roof and I personally use firestone which comes with a 20 year guarantee and 50 year life expectancy each roofer will have there own preferences to materials but that would be mine and I would use a sun tunnel you can get many makes of these but they are excellent at letting light in and no need to alter the rafters to fit thanks and all the best

Answered 24th Jan 2017

W.E.B Roofing and Building

Member since 17 Jan 2017

I would recommend grp fiberglass system applied as a warm deck roof and go for a sky pod window witch comes in different sizes for more light in to the living area

Answered 26th Jun 2017

Matthews Roofing Cumbria

Member since 11 May 2016

I would go with green minrell torch on with a pod window as you can heat seal the felt around the bottom of the window base and prevent leaks and if done correctly will last 15 years one of the oldest and best roofs you can get hope this helps you .cheers roofcheck

Answered 16th Aug 2017


Member since 6 Dec 2016

If roof is only 9years old depending on the leaks how bad thay ar if is bad 1 recommended re roof with a good thickness of mineral felt to heat torch on get good grade felt an good board s for under lay or u can repair an fixe roof dry roof off u can use arcypol liquid sealant guaranteed recommended from customers dome window s can leak if fitted correctly within a good snugg fite make sure edging s at double layered correct not gaps if leadworks make sure get lead dressing tools for lead meeting felt regard s crownroofing

Answered 8th Sep 2017

Crown roofing

Member since 8 Sep 2017

I would recommend either fibreglass or EPDM. On a warm deck roof. Both have a similar life expectancy. Both need to be applied by trained professionals as neither is as easy as it looks to install and poor installation will mean having to renew after a short period.

When it comes to letting natural light in them it's all a matter of personal taste really. There are great products available in various designs that will do the same job.

Also be careful going for the cheapest quote as sometimes there's a reason these tradesmen are cheaper!
Do your homework on the company first.

Good luck.

Answered 29th Sep 2017

Toprank Roofing & Building LTD

Member since 22 Mar 2016

I would reccomended GRP Fibreglass as it’s a very robust product that comes with a 20 years guarantee from the manufacture. I have never had any issues with this it has no seems / joins as it’s fitted great stuff

Answered 26th Jun 2018

Storm Shield Roofing Services

Member since 26 Jun 2018

A 9 year old flat roof shouldn't be giving you problems to be honest. So I'd be advising you repair the existing roof. As far as the roof light is concerned velux windows work on pitched slate and tiled roofs with the correct flashing kit. Theres loads of flat roof lights you can buy from the popular auction sites. You can buy the timber for the upstand the roof light sits on. Ideally 4×2. Gives you a good height for making water right. Any other questions just as me.

Answered 6th Jul 2018

Roofing Specialist Scotland

Member since 29 Jun 2018

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