Is this a fair quote??

[Seasider]

Good morning

I have a double garage with concrete roof with lots of leaks. It has steps to the side and we walk across the roof for access to further steps up to the house. It is just sealed with a barrier paint and shingle on top. It’s approx 30-32sqm. 
My quote is £5600 for 3 layers of torched felt (?) and lead flashing. Is this reasonable? Thanks for reading and replying. 

[markc]

Very difficult to comment on prices without knowing where? Access? Etc etc. but roughly £175/sq meter for 3 layers and flashings doesn’t sound too far out.

[Seasider]

Hi Markc

thanks for your reply. Do I need 3 layers as it’s not part of the house? Quite seemed quite high but I guess I have to deal with it! 
I’m in a Devon town and garage is easily accessed. 

[ToughButterCup]

It is common to get three quotes for any build project - part of the Due Diligence process.  If you don't go through that process (need not be as complex as implied in the link given) you increase the risk of coming back to us with a (commonly heard) tale of woe.  In short ; ask, talk, look. 

 

Lets speculate about the costs involved - this is PURE speculation

• Ancillary works: 2 days  £400
• Felt 3 rolls (3* 275)  £825
• Skip 8 yards  £280
• Torch-on felt kit  £300
• 2  guys 2 days (4 man days) £800
• Equipment hire  £100
• Incidental costs (fuel , phonecalls , consumables) £100
• Profit  ( roughly the sum of the above) ~ £ 2000+

That  coffee house fag-packet calculation makes the quote above about right.

 

Yes, you'll get it done for less.  But consider that he  might do a good job - in which case you've started to build trust. And thats valuable.

Network hard: has yer man worked in the area long? Who has had work done by that firm before? Go and look (or sneak a look) . Talk to as many as you can about the builder - ask at local estate agents for anyone who knows him . Mind you in Devon the Jungle Telegraph works particularly  well if my experience is anything to go by.

 

Other members will have a view about whether 3 layers of felt is enough straight on to concrete where the surface will be walked on every day. My instinct is that it isn't ....

 

We aren't experts. Just nosey, hard-bitten (often nosey) self builders with long memories. There is no substitute for doing your own research: it builds confidence and decreases risk. 

Photos please. 

PS, I had no idea how acidic ( alkaline? ) seagull shooshoo is..... 

[markc]

55 minutes ago, Seasider said:

Hi Markc

thanks for your reply. Do I need 3 layers as it’s not part of the house? Quite seemed quite high but I guess I have to deal with it! 
I’m in a Devon town and garage is easily accessed. 

If it is used as a garage or store and not open to the living accommodation then you don’t need three layers. As you walk over it have they allowed extra for local extra layers for a path of some kind

Edited November 14, 2023 by markc

[ToughButterCup]

One stone (a local flint will do)  picked up on a shoe heel and traipsed over some felt ..... even 3 layers hmmmmm......

[Alan Ambrose]

I would be inclined to check out an EPDM solution with carefully made duck boards or similar to avoid puncturing the bit your normally walk over. Should be much cheaper and probably last longer. Use the thickest EPDM you can find.

[ToughButterCup]

@Seasider raises an interesting question: How can you make a leaky concreted flat roof waterproof ?  Is a triple layer of felt adequate for the job? 

My feeling is that in this case (because  the the roof doubles as a footpath) it isn't - Or if felt  is OK for a while - it soon won't be : shoe, stone, heel, puncture, leak, frost, thaw, bigger leak, peed off @Seasider.

 

Somehow, shoes need to be kept off that roof. Marine ply walkway on 4 by 4 bearers? 

Edited November 14, 2023 by ToughButterCup

[SteamyTea]

@Seasider

As you are in the devil's county, you should easily find someone that thinks they know how to GRP the roof.

Done properly you will be able to walk in it for the next 50 years.

Felt and EPDM do not make for good foot paths.

[LnP]

7 minutes ago, SteamyTea said:

@Seasider

As you are in the devil's county, you should easily find someone that thinks they know how to GRP the roof.

Done properly you will be able to walk in it for the next 50 years.

Felt and EPDM do not make for good foot paths.

+1 for GRP. I've just done a flat roof in GRP and am pleased with the result. Definitely better than felt. 

[SteamyTea]

5 minutes ago, LnP said:

+1 for GRP

It may have to be done with a polyurethane resin rather than a polyester, it all depends what sealant has been used already.

There are a number of ways to make a strong catwalk on a roof, a non slip finish is important though.

[ToughButterCup]

14 minutes ago, SteamyTea said:

...

Done properly you will be able to walk in it for the next 50 years.

....

 

I was hoping you would join in @SteamyTea. 

 

In terms of GRP walkways, what does .... Done properly ... mean in practice ?

I ask because I'm not aware of any GRP walkways - or perhaps I just don't notice them when I walk on them ?

 

@LnP  was your GRP roof also used as a walkway ?

[Seasider]

Thanks to everyone for their input. Lots to think about! 
currently there are pavers for the walkway and rest of roof is covered in shingle. 
I better crack on and get more quotes 👍

[SteamyTea]

34 minutes ago, ToughButterCup said:

Done properly ... mean in practice

By someone that knows what they are doing, so not a chancer that 'made a canoe once'.

36 minutes ago, ToughButterCup said:

not aware of any GRP walkways - or perhaps I just don't notice them when I walk on them

We made the walkway at St. Mary's Hospital in London. Not sure if it is still there as it was nearly 40 years ago.

A lot of marinas have GRP walkways.

You generally will not notice them. They are constructed in a modular fashion to aid installation, they are not made to be light and strong, just lighter than steel and concrete.

[LnP]

2 hours ago, ToughButterCup said:

 

@LnP  was your GRP roof also used as a walkway ?

It's an 11 m x 4 m roof terrace, which means we walk on it. It has a parapet around it so the GRP goes up and over the top of the parapet under the masonry copings. Two layers of 450g fibreglass mat, two pack polyurethane resin and top coat. Including flashing, trim, rollers, acetone, parapet rain outlets etc the materials came to about £1300. I got a builder to install it and it took him about 4 days with a labourer, so about £1,000 labour. I decided not to use non slip top coat because I was concerned about keeping it clean. It's only been in a few months and so far don't see the need for non-slip. If I change my mind I'll just put a coat of non-slip top coat on it.

[Alan Ambrose]

Personally I hate fibreglass after a bunch of experience with glass, resin and gf boats in my youth. You'll be sheltered from the installation yuk, but I wonder what the real expected lifetime is? Used as a terrace, I would expect it to crack under point loads, then leak, then need replacing. 

[LnP]

16 minutes ago, Alan Ambrose said:

I would expect it to crack under point loads, then leak, then need replacing. 

All good points. We'll see. I can put decking on top of it if I have these kinds of problems. I designed it with that in mind, e.g. set the handrail on the balustrade higher than the 1100 mm required by building regs to allow for the height of the decking.

[Alan Ambrose]

>>> set the handrail on the balustrade higher than the 1100 mm required by building regs to allow for the height of the decking.

 

You do know that thinking ahead is actually forbidden on BH forum?

[SteamyTea]

6 hours ago, Alan Ambrose said:

but I wonder what the real expected lifetime is? Used as a terrace, I would expect it to crack under point loads, then leak, then need replacing. 

I think you have highlighted a common misconception about GRP.

If you build a suspended walkway, you would expect a proper design.

Something built from GRP that does the same job also needs a proper design.

What it does not need is someone that thinks they can just mix a bit of resin and hardener together in a bucket, soak some chopped strand mat with it, run a paddle roller over it a couple of times, then think the job is done.

 

I ran a composite factor in the Midlands back in the early 1990s. Half the workforce came from Reliant Cars.

Reliant, with a glass manufacturer and a couple of resin makers had developed a system that was designed to make the manufacture of car panels easier and cheaper. The system worked well. Was used in the DeLorian as well.

Trouble was, those Reliant worker were not using the same materials at my factory, so they used the same manufacturing technique as they had at Reliant.

The quality was shit, absolutely hopeless, it lacked a decent finish, had high structural failure rates, and rejects that needed remedial work was over 90%.

 

Why I always say, GRP has to be done correctly.

It is not hard to do right, but it is very easy to do it wrong though ignorance.

 

[ToughButterCup]

In relation to the OP then, are we saying to @Seasider

• Felt the roof to cure the leaks
• Design and build an appropriate walkway using GRP
• Fit the walkway

Because if we are, we've hit yer man right in the bank-balance. 

 

@Seasider - if you can bear it - ask for a quote ( .... erm 3 quotes ) to design, build and deliver you  a @SteamyTea - approved walkway.

Thinking of your bank balance, might it be possible to just have the walkway, and leave the rest of the flat roof 'til later?