Flat Roof Replace and Rough Cost

Joined
4 Aug 2014
Messages
79
Reaction score
4
Location
West Midlands
Country
United Kingdom
Time is... i'll try not to swear! Something that should have really been done a while ago has got worse and, where did all the time go!!!???

I have a kitchen extension with an old style flat roof, it's pooling water and coming through into the kitchen. I'm no expert but I think it needs to be replaced quite quickly.

It's about a 3m x 4m extension and I would like the quickest / cheapest solution to get the house on the market and sold. I know quickest / cheapest might seem typical but my reason is this... a cold deck with added cross ventilation (which doesn't currently exist on it) would only increase the height very slightly and would give the extension enough life before any future person would actually want to knock the extension down and build a new one across the whole of the back of the house. No point doing more expensive warm deck solutions and certainly not pitched solutions when, in all honesty, the whole extension will be knocked down and rebuilt within 10 years.

So... in the midlands area, what would be a reasonable quote I can aim for to simply redo the flat roof but adding some ventilation?
 
Sponsored Links
Joined
2 Feb 2006
Messages
46,244
Reaction score
3,221
Location
Staffordshire
Country
United Kingdom
Time is... i'll try not to swear! Something that should have really been done a while ago has got worse and, where did all the time go!!!???

I have a kitchen extension with an old style flat roof, it's pooling water and coming through into the kitchen. I'm no expert but I think it needs to be replaced quite quickly.

It's about a 3m x 4m extension and I would like the quickest / cheapest solution to get the house on the market and sold. I know quickest / cheapest might seem typical but my reason is this... a cold deck with added cross ventilation (which doesn't currently exist on it) would only increase the height very slightly and would give the extension enough life before any future person would actually want to knock the extension down and build a new one across the whole of the back of the house. No point doing more expensive warm deck solutions and certainly not pitched solutions when, in all honesty, the whole extension will be knocked down and rebuilt within 10 years.

So... in the midlands area, what would be a reasonable quote I can aim for to simply redo the flat roof but adding some ventilation?
What makes you think cold deck (with the faff of venting etc) is cheaper? You would be an idiot not to go with a WD solution whilst you have the opportunity.

Anyhoo upwards of £3'600 plus scaffold (£300ish).
 
Last edited:
Joined
4 Aug 2014
Messages
79
Reaction score
4
Location
West Midlands
Country
United Kingdom
I was thinking more along the lines of £50 all in. Just kidding.

I know what you are saying regards the warm deck. My thinking on the other side was, I am sure I have read that to meet the U rating the warm deck has to be quite thick these days and so will heighten the roof to a point that just adds extra issues with building control (and extra complications on the neighbouring joining pitch roof etc and I was reading that in general, the cold deck is cheaper and is a direct like for like replacement and as I just need a quick roof recovering to last maybe 5 - 10 years before it's all pulled down, it really only needs to be done to that kinda standard.

I have drilled a hole underneath and measured the rafters and they are 130mm. Is it still also an option under building control to just pack them with insulation, leaving no space, and then there is no need for ventilation? Honestly just looking at a quick roof and get this thing on the market.
 
Joined
15 Sep 2017
Messages
29,471
Reaction score
2,192
Location
S. Uplands
Country
United Kingdom
I was thinking more along the lines of £50 all in. Just kidding.

I know what you are saying regards the warm deck. My thinking on the other side was, I am sure I have read that to meet the U rating the warm deck has to be quite thick these days and so will heighten the roof to a point that just adds extra issues with building control (and extra complications on the neighbouring joining pitch roof etc and I was reading that in general, the cold deck is cheaper and is a direct like for like replacement and as I just need a quick roof recovering to last maybe 5 - 10 years before it's all pulled down, it really only needs to be done to that kinda standard.

I have drilled a hole underneath and measured the rafters and they are 130mm. Is it still also an option under building control to just pack them with insulation, leaving no space, and then there is no need for ventilation? Honestly just looking at a quick roof and get this thing on the market.
if you are selling the house -just patch it up with roof seal

if you are living in it for another winter and want it done cheap, then buy an EPDM kit and do it yourself over the summer, dont bother with insulation -you might need to replace the boards and firrings if its pooling badly

by the time you sell it the surveyor wont be able to tell when the roof was done
 
Sponsored Links
Joined
16 Sep 2006
Messages
2,329
Reaction score
325
Location
Fife
Country
United Kingdom
Assuming the existing roof isn't 'that' bad (any chance of some pics?) and given you're putting it on the market (soon?) I'd use something like this, over the entire area and properly applied to make it watertight:

 
Joined
15 Sep 2017
Messages
29,471
Reaction score
2,192
Location
S. Uplands
Country
United Kingdom
how so?

house surveyors always moan about flat roofs -and one that is pooling and knackered will be noted

it will be used as a bargaining chip by the buyer


Its pointless spending money on a new roof because you wont get that back on the sale

I could argue "its not nice" they way buyers play games to get the price down
 
Joined
11 Nov 2020
Messages
1,078
Reaction score
134
Location
Mercia
Country
United Kingdom
I had a 2m x 4m flat roof done a couple of years ago, all the old lead taken off and a fibreglass replacement for less than a grand.
 
Joined
4 Aug 2014
Messages
79
Reaction score
4
Location
West Midlands
Country
United Kingdom
I patched the spots with some roof sealant, bitumin type stuff I think it was, about 2 years ago or so but it's gone beyond that now, the boards absolutely are totally shot.

It think it's probably a good shout to just take up the existing, put down some new boards and re-cover, leaving the existing insulation in place. ie, it's basically a big repair. I feel in the same park as Notch7, weighing up the situations if I spend £3k - £5k for example on a new roof, I am not going to get that reflected in the sale, the true reflection will probably be the quick cut and cover solution. The buyer won't give a crap about me or my money or my family, the same argument will be had whether I spend £1k on the roof or £5k on the roof for the purpose of them trying to pull my price down only for them to know they will pull the whole extension down before long anyway.

If it's a roof that lasts even 5 - 7 years, I have not done anyone any injustice at all.

I appreciate all the inputs.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Top