DIY replacing flat roof.

[kindai]

Ok either I am

a) Insane

or

b) Insane

but I am currently looking at a horrendous bungalow thats up for sale with a flat roof.

As they say a picture speaks a thousand words...

The price matches the condition. The entire roof is f-ed to put it lightly. The interior walls are all plasterboard and the water has gotten in and long story short the whole place will need gutting.

Now rebuilding internal stud walls is easy enough, the question comes to the roofing.

As far as I can tell, for the most part the construction itself for the roof is nothing more than glorified decking with a few bonus features to add (a slight angle to allow water to run off, air gap, insulation etc). But the quotes to replace a full roof seem entirely disproportionate to what I consider the actual work to be given the basic materials.

So this leads me to the question, is this actually something that is in the realms of DIY? Or is it just not worth considering?

 

[Thecaferacer]

Is the entire roof flat? Are you re-engineering it? It's a tough one to answer as flat roofs are relatively child's play with modern EPDM sheets. But depends if it's being married to a pitched roof etc .

 

[kindai]

Is the entire roof flat? Are you re-engineering it? It's a tough one to answer as flat roofs are relatively child's play with modern EPDM sheets. But depends if it's being married to a pitched roof etc .

Yup, wall to wall entirely flat.

 

[bremen1874]

Could you put a pitched roof on it?

Flat roofs are a liability. I'm sure there are some decent modern options, but I still wouldn't want one.

Insurance companies don't like flat roofs either.

 

[Maccapacca]

False economy.

Most of the cost of a flat roof is materials of which you probably won't get at a trade or discounted rate. Plus your calculations won't include all the little odds and sods trims etc.

The labour content is relatively small that'll be you're only saving. Do you want to run the risk of it leaking over your newly decorated house and having no one to call on to save £800 ish ?

 

[Lakeland]

False economy.

Most of the cost of a flat roof is materials of which you probably won't get at a trade or discounted rate. Plus your calculations won't include all the little odds and sods trims etc.

The labour content is relatively small that'll be you're only saving. Do you want to run the risk of it leaking over your newly decorated house and having no one to call on to save £800 ish ?

I'd agree with this, get it done properly as the smallest of holes on a flat roof will result in a big headache.

 

[Thecaferacer]

Flat roofs have come on leaps and bounds with EPDM.

However by the time you have costed on the roof joists man enough for the job, sheathing OSB and materials for the EPDM, you aren't far off trusses and tiles for a pitched roof.

Plus pitched roofs look better, gives you a roof cavity to run pipes, wiring with easy access, can hide your water tank up there and can be better insulated.

 

[Psycho Sonny]

i'm guessing he wants to do it on the cheap as he won't be living there and renting it out so wants maximum return on investment.

so he doesn't care what is better but what will work and is cheapest.

 

[kindai]

i'm guessing he wants to do it on the cheap as he won't be living there and renting it out so wants maximum return on investment.

so he doesn't care what is better but what will work and is cheapest.

Correct. Inside it needs entirely ripping out. So when it is back to a shell it will quite literally be 4 walls (well, 6 as its a strange layout) with utility supplies, no roof and no internal structures.

I have access to trade accounts for the materials and am pretty good at DIY in general. Would likely go for a warm flat roof option. Pitched would be nice but prohibitively expensive given the layout of the walls. But given it would effectively be starting from scratch, nothing to get in the way, once the main joists are in would be able to fly along. I would get a pro in to do the final seal but the rest seems easy and cheap enough.

 

[Psycho Sonny]

Correct. Inside it needs entirely ripping out. So when it is back to a shell it will quite literally be 4 walls (well, 6 as its a strange layout) with utility supplies, no roof and no internal structures.

I have access to trade accounts for the materials and am pretty good at DIY in general. Would likely go for a warm flat roof option. Pitched would be nice but prohibitively expensive given the layout of the walls. But given it would effectively be starting from scratch, nothing to get in the way, once the main joists are in would be able to fly along. I would get a pro in to do the final seal but the rest seems easy and cheap enough.

as it's structural you won't really know about load bearing, etc i'd get a pro in to do it but I can see why you want to try and do it on the cheap and just wanted to make it clear to others as you don't care about what is best but what is cheapest and will work long term. otherwise you will just get contact replies saying do it properly.

if you had the cash i'd be tempted to knock the full thing down and rebuild from scratch and get 2-3 townhouses on the land. much more capital needed up front but much bigger returns to be had.

 

[kindai]

if you had the cash i'd be tempted to knock the full thing down and rebuild from scratch and get 2-3 townhouses on the land. much more capital needed up front but much bigger returns to be had.

Yea, nowhere near that much money lying around unfortunately

as it's structural you won't really know about load bearing, etc i'd get a pro in to do it but I can see why you want to try and do it on the cheap and just wanted to make it clear to others as you don't care about what is best but what is cheapest and will work long term. otherwise you will just get contact replies saying do it properly.

I have a couple of mates who are builders who are going to price me up, on the flip side theyve both offered to help out as I've sorted them out in the past when theyve needed a hand with some things.

The project while "big" is not difficult, in fact, in my mind at least because it would be gutted with only the utility points left, once the roof is watertight the inside should fly up because we can route pipework and electrics efficiently as possible.

 

[JBuk]

Don’t do it, talking from experience these things seem like a great idea at the time but it’ll suck the life out of you as well as probably costing far more than you will budget for

 

[fastwunz]

It is unlikely that you will secure a mortgage with a main stream lender on a bungalow with a 100% flat roof - we Surveyors and indeed the lenders don’t like them when the total roof area is over 25% flat owing to short life spans, often dodgy and frankly lazy construction and the resulting deterioration you have demonstrated on your smashing photos.

Effectively a house with a 100% flat roof has very limited marketability.

 

[Usher]

The days of chipboard and green mineral felt are gone, cover any flat roof with Butyl rubber sheet & it will last for decades,it's the same heavy duty stuff used to line lakes and ponds. Ours was done 37 years ago and shows no signs of failure.
Fibreglass roofs however can and will crack with expansion

 

[Lakeland]

The days of chipboard and green mineral felt are gone, cover any flat roof with Butyl rubber sheet & it will last for decades,it's the same heavy duty stuff used to line lakes and ponds. Ours was done 37 years ago and shows no signs of failure.
Fibreglass roofs however can and will crack with expansion

A school close to me had a roof like that installed on part of a brand new building and 7-8 years later they still have leaks that cause 10s of thousands of £ worth of damage.

 

[blueboy2001]

You need Building Regulations approval for the roof replacement as its classed as renovation of a thermal element. You'll need to insulate it to current standards.

I'd confirm that ceiling and the walls are definitely plasterboard too, because a lot of cheap housing of a certain age used Asbestos Insulating Board (AIB) quite extensively.

 

[Usher]

A school close to me had a roof like that installed on part of a brand new building and 7-8 years later they still have leaks that cause 10s of thousands of £ worth of damage.

A butyl or fibreglass roof on the school?

 

[Lakeland]

A butyl or fibreglass roof on the school?

Fibreglass. Not the whole roof just a part of it but the flat roof is the only part that leaks and boy does it leak!

 

[Usher]

Fibreglass. Not the whole roof just a part of it but the flat roof is the only part that leaks and boy does it leak!

I guessed so, Butyl withstands a lot of movement and stress with no problems, I suppose the school keeps paying for endless fibreglass repairs whereas covering it in Butyl over the top of the fibreglass would fix it for good

 

[Lakeland]

I guessed so, Butyl withstands a lot of movement and stress with no problems, I suppose the school keeps paying for endless fibreglass repairs whereas covering it in Butyl over the top of the fibreglass would fix it for good

I think it was all fixed under snagging but they did repeatedly try and redo it in fibreglass. Part of the problem was they couldn’t find where the actual leak was!