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Builder opinions wildly differing

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 ogreville 23 Nov 2022

My two storey house has water leaking into the attic at the gable end and Im having an issue with builders/roofers. There are some cracks in the render on the chimney stack. 
 

I have spoken to two builders.  One has quotes €6,600 to remove the whole chimney stack and re-line and cap it with a scaffold up. Happy to pay this if this is what’s needed. 
The other builder seemed to think it was just a case of jumping up a ladder and patching the render - no price provided yet. 
 

My surveying engineer thinks the flashing needs replaced, but told me to get a builder out as an expert eye.  
 

How can a person get competitive quotes if tradespeople have wildly differing opinions on spec?  
 

Any advice out there?

1
 pencilled in 23 Nov 2022
In reply to ogreville:

Try builders forums maybe. Did the chimney guy show you the ingress? I’d check that.  Patching render in my experience is often a fairly temporary fix but worth trying if it’s the cheaper option. We had a chimney stack removed without replacing it which was a permanent fix. My youngest has a bigger bedroom now too. My only advice is to find a tradesman you trust and stick with them or their trusted referrals, which isn’t particularly helpful, sorry. 

1
OP ogreville 23 Nov 2022
In reply to pencilled in:

We have a wood burner, so the preference is to keep the chimney. The water ingress is coming from the area around the stack but it is impossible to tell if it is the render or the flashing. 
My guess is that a builder couldn't guarantee 100% what the source is either. Some will quote to do a patch job, hoping this will resolve without a call back and some will quote to strip the lot out and start again to sort it. 
Leaves me in a tricky spot knowing which option is correct. 

 wintertree 23 Nov 2022
In reply to ogreville:

Why would a builder quote to remove a chimney that you use?

People have been able to make roofs pretty water-tight around chimneys for centuries.

Something fishy here.  Ask them for their reasoning.  Unless there’s something exceptional about your case it sounds like they’re trying it on…

3
 daWalt 23 Nov 2022
In reply to ogreville:

jump up a ladder yourself and have a close look, and I mean a proper close look. you might even want to consider taking a watering can with you.

you could then take lots of photos, which might help you (or even any roofer) understand the lie of the land.

one other thing to bear in mind is wind driven rain can get into and under almost anything if it's blowing hard enough.

 Billhook 23 Nov 2022
In reply to wintertree:

> Why would a builder quote to remove a chimney that you use?

> People have been able to make roofs pretty water-tight around chimneys for centuries.

> Something fishy here.  Ask them for their reasoning.  Unless there’s something exceptional about your case it sounds like they’re trying it on…

They have been repairing faulty or damaged chimneys for centuries too.!!

Post edited at 20:17
OP ogreville 23 Nov 2022
In reply to wintertree:

They have quotes to remove and completely rebuild the existing stack with a new cap and relining of the flue. 

 wintertree 23 Nov 2022
In reply to ogreville:

> They have quotes to remove and completely rebuild the existing stack with a new cap and relining of the flue. 

Ah, I thought you meant to cap it at roof height.  So, question is why do they think it needs rebuilding rather than repointing and remedial works on the roof?  You need to push them for the reasons and dig in to it if you want to understand the difference in approaches.

 craig h 23 Nov 2022
In reply to ogreville:

The trouble with water ingress into a building is it's quite often hard to track down the origin of it unless it sticks out like a sore thumb.

We still have an ongoing leak, flashing around the chimney has been replaced, chimney repointed and all slates and roof tiles are secure. There is a possibility the water may be coming through the roof next door and then tracking along the roofing timbers to then emerge in our roof space.

I use to do a fair bit of sealant work / leak repairs on tower blocks, often the problem was caused by degraded sealant a few stories above and to the side of where the end result manifested itself.

Starting from the top and working down does seem an obvious approach if there is no obvious defect in the first place.

In reply to ogreville:

Do you have a mate with a drone? Get them to fly it up there and have a proper good look with the camera. You might be able to see well for yourself exactly what the issue is.

 PaulJepson 23 Nov 2022
In reply to ogreville:

Where are you based? I dont know if it differs wildly being  gable stack rather than a mid-terrace (I'd have thought maybe a bit more brick building but easier access), but 6k sounds like a lot to remove a stack. I was quoted 2k as a standalone job or £800 if done with a re-roof. That's a 4 chimney stack in a mid-terrace. 

Doing the lead flashing, soakers and pans around a normal stack will be in the region of £500. 

Chimneys are an absolute nightmare to be honest. They're a real point of weakness in a buildings envelope. It could be any number of the below, or several of them:

  • Cracked or poor condition flaunching
  • Cracked or poor condition pointing
  • Spalled or absorbent brickwork
  • Cracks in the render
  • Bridge in the chimneys damp course
  • Failed flashing or pan
  • Cracked tiles around stack

If you are wanting to keep the chimney for your burner, it might have to be a bit of trial and error on fixing the above, and getting a few different quotes in. If there are cracks in the render then that definitely isnt helping, so start with that and maybe the lead while they're at it.

Roofers will always want to do the thing they can guarantee will work, which is take it down and roof over it (not to mention it gives them some extra work/money). That doesn't mean it's the only option, it just means they arent sure what the problem is and dont want you ringing them up and telling them you still have a problem even though they did this or that. 

 Wainers44 23 Nov 2022
In reply to ogreville:

Let's blame the builder shall we....

I know that's not what you meant but from a rough description on a forum it's hard to tell what's fair advice and what isn't. Looking at the problem might not help much either until its taken apart. 

I could be a builder,  but have also had leak or other chimney issues, so my four penny worth...

Flashings are classic weak points, but the work in behind is harder to suss. Are the soakers all installed correctly and with render (over brick?) it's difficult to tell? Sometimes the leak is bringing in salts,  which you can see, which means it's more of a masonry or render problem rather than dodgy slates?

Our chimney looked fine, until one day it wasn't when the TV aerial,  fixed around the chimney,  suddenly cheese wired one of the joints and nearly put the chimney through the roof. Issue was the sulphate attack on the mortar by the fire/smoke. That happens inside to out so cannot be easily seen. 

Your chap who priced to take down and rebuild maybe saw that in yours? 

Hope you get it sorted. 

3
 Kemics 23 Nov 2022
In reply to ogreville:

Did they actually get up on the roof and have a good look around? 

I had a leaky chimney and had a builder come round who had a look from the garden and suggested replacing the flaunching and flashing but would be £1800 as it's two blokes and scaffolding. Had a second quote from a roofer who looked from the garden and suggested rebuilding the stack, two blokes and scaffolding £6k. 

I wasn't sure given the two different opinions so asked a 3rd guy, who actually climbed on the roof and found 2 cracked caps which he replaced for £50. It might be case as Pauljepson suggested that people are just advising belt and braces solutions so it works. 

In reply to ogreville:

I'm not saying that missing render can't cause dampness, but (without having seen your house!) if I wanted to line up suspects I'd put that in 4th place

  1. Flashing - fix it
  2. Some other roof leak - roofer to get up ladder and find it and fix
  3. Condensation in the loft - add some roof/tile vents. A particular problem if a cavity wall (which are there to prevent damp) and wall cavity is blocked up by cr*p blown into it on some government insulation scheme a few years ago or if loft insulation doesn't leave a little gap round the edges
  4. Pointing and render - fix them

Get into the loft and check from the inside have a good rummage about, water runs down so check lower and work upwards. If you have bitumen felt or modern roof membrane, at an overlap slide your hand in there and feel for wet. The more you find out, the more likely you can make the right judgement on the builders' advice.

Anyone who diagnosed this purely from the ground (didn't get up on roof) while scratching their chin is not to be taken seriously (including me). Someone needs to get on your roof 

Good luck 

Post edited at 07:19
 Tringa 24 Nov 2022
In reply to wintertree:

> Why would a builder quote to remove a chimney that you use?

> People have been able to make roofs pretty water-tight around chimneys for centuries.

> Something fishy here.  Ask them for their reasoning.  Unless there’s something exceptional about your case it sounds like they’re trying it on…

Agree. I'd be concerned that the builder did not ask if the chimney was in use before suggesting removing it.

Dave

In reply to ogreville:

I assume your chimney actually has a DPC in it? How old is the property?

1
 jkarran 24 Nov 2022
In reply to ogreville:

> Leaves me in a tricky spot knowing which option is correct. 

I'm not sure you'll get a definitive answer, the definitive diagnosis would be by addressing the issues individually until the water stops. If the cheap option is cheap enough it's probably worth a gamble. If it doesn't work you've lost a few hundred quid, if it does you've saved a few thousand.

jk

In reply to ogreville:

We have two wood burners and we also had water ingress on both chimney stacks. Our house was built in 1901 of limestone, so quite and water ingress is not totally unexpected. We started off with targeted patch repairs off a ladder, but a failure. In the end we had both gable ends scaffolded, the chimney stacks raked out and repointed and most importantly the haunching replaced. We also had different chimney caps fitted to stop rainwater. After that I sprayed both gable ends and chimneys with water repellent. Dry house!

In reply to Philb1950:

> After that I sprayed both gable ends and chimneys with water repellent. Dry house!

Until the damp starts because the water repellant doesn't let the old limestone wall breathe... 😉

2
 Jimbo C 24 Nov 2022
In reply to ogreville:

I think your surveyor is right. Under the render should be lead flashing that re-directs water running down the stack onto the roof slates / tiles. The render is most likely just there to improve appearances or cover up a bodge and is not (or should not be) the waterproofing.

I would rather give builders instructions than ask for their opinion. Something like: hack off enough render to expose the flashing (or reveal a lack of flashing), then repair / replace / install new flashing and then patch repair the render. Ask for itemised costs so they don't rip you off if it ends up only being a minor flashing repair. Get them to send you photographs of it before and after the repair and agree the final cost based on how much lead they had to use.

Post edited at 14:18
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 daWalt 24 Nov 2022
In reply to Ridge:

That though crossed my mind too. And it can take 10 or 20 years before anything is noticeable. 

(But let's not go down that road today )

OP ogreville 24 Nov 2022
In reply to Toerag:
 

its around 15 to 20 years old. I don't know if there is a DPC though. 
 

In reply to ogreville:

>  

> its around 15 to 20 years old. I don't know if there is a DPC though. 

If it's that new you'd probably expect there to be a complete lead tray through the full cross-section of the chimney like this:- youtube.com/watch?v=7tpc7Xiy7sI&  and it's quite unlikely that this would leak.  I stand to be corrected though!

In reply to ogreville:

Our roofer showed us pics of our chimney while reroofing about 3 years ago. He offered to rebuild, render and put flashing on our half for extra £500. Of course scaffolding was already in place. Our neighbour declined same offer. Attaching my pics of our half (whiter) and neighbour's. Essentially the chimney on neighbour's side is a pile of bricks (as ours had been) perhaps supported by fairly recent rerendering when he had a roof extension. Perhaps surprisingly neither of us had had obvious damp issues though stuff fell down chimney regularly.

Incidentally we had our chimney pots capped as part of the original quote, however when I removed one of the sprung caps as I was thinking of having a gas fire and needed to replace it, I found that half the area of the chimney duct had been blocked by a "slate" used as a base for the pot. 


 hang_about 24 Nov 2022
In reply to ogreville:

Of course your situation may be different, but I had a leaky chimney and first suspect was always flashing (and second suspect and third.....). The problem was finding a roofer competent to fix it. The problem re-occurred every other year until I found a good roofer. My favourite was one of the poor roofers telling me the ceiling had come down in the attic due to water ingress. The ceiling had come down, there was some water ingress, but he'd also put his foot through the roof (very obvious 'foot-sized' hole he conveniently covered up).

In reply to hang_about:

Did you call him out on it? 

 OCDClimber 24 Nov 2022
In reply to ogreville:

I wish I knew the answer.  I had a roof leak on a dormer.  I was quoted £3500 to remove the tiles replace the felt and put the tiles back. Another roofer had a quick look replaced a foot or so of lead flashing and didn't even charge me. This solved the problem.

 hang_about 24 Nov 2022
In reply to Dan Arkle:

No. A long saga of dodgy roofers. Finally found a good one. 

In reply to oldie:

Is there anything under the gap between your tiles and your neighbours?! Who on earth would think that was a good idea?

In reply to Toerag:

Didn't notice that! How is it even watertight?

In reply to Toerag:

> Is there anything under the gap between your tiles and your neighbours?! Who on earth would think that was a good idea? <

There is a flat, plastic channel about 30cm wide with raised ridge down edge. This was put in when neighbours had new roof extension before we had new roof. Mortar under tiles onto channel. I don't like it either as I imagine there could be water ingress around mortar especially when it cracks. Apparently this is an accepted method.  IMO the gap is also far too narrow and could be easily blocked and I'm not sure if the nailing of the bounding tiles conforms to regulations.

Interesting you pointed it out.

More questionable work has recently become apparent. The front fascia and soffits were not removed as specified and the new plastic was simply put over the old wood ones. When I examined the vents in this soffit I found one was useless as its hole was through the plastic but not the underlying wood ! and another was simply round marks made by incomplete drilling with no attempt to even place the plastic vent grill at all. Gutter leaking where there if a rough join over a kink due to edge of new fascia being above adjoining neighbours old fascia. Many tile nails missing battens and protruding through membrane including one long line which has nearly treppaned me. One new sprung C cap over a chimney pot was missing spring and simply had 4 blobs of mastic to hold it. As roofers were finishing I noticed that where there should have been venting around periphery of roof but only half was in present....compromise was the soffit vents. The plastic vented ridge had continuous breathable roof membrane under it (ie not actually venting)....agreed compromise  cutting slits from inside loft. Just mentioning these points in case they are useful to others. Much due to inadequate supervision by roofing company owner.

In reply to oldie:

> There is a flat, plastic channel about 30cm wide with raised ridge down edge. This was put in when neighbours had new roof extension before we had new roof. Mortar under tiles onto channel. I don't like it either as I imagine there could be water ingress around mortar especially when it cracks. Apparently this is an accepted method.  IMO the gap is also far too narrow and could be easily blocked and I'm not sure if the nailing of the bounding tiles conforms to regulations.

Sounds fair enough. It's unlikely to be any worse than the tiles themselves other than the potential for blocking and subsequent sideways 'flooding'. That could be resolved by filling the gap with mortar or mastic all the way along its length.

> Much due to inadequate supervision by roofing company owner.

Or more likely, cost-cutting by roofing company owner "Let's see what we can get away with lads"

In reply to ogreville: From personal experience of doing this kind of work, £6600 to remove the chimney and simply cap it is a straight rip off. Taking a chimney down is not a skillful job, it's the rebuild that needs the knowledge.

I've recently taken down and rebuilt a chimney with this exact issue. In this case the (stone) chimney was rotten and we could only reuse about 10% of the stone, it was that bad. The flashing was absent and the concrete render was very poor. A complete rebuild, new chimney pots, immaculate flaunching and lead flashing have completely solved the significant leakage in the attic conversion. We used our own scaffold tower which reduced costs, but overall the bill was £3200. Scaffolding would add another £1000-1500 depending on the deal you get.

Multiple opinions are essential. Getting people to come and do the work is strangely impossible.

If it's a question of cost for you, I would suggest doing the simplest things first.

1) Make sure your pots have cowls (£5 per cowl from B&Q)

2) Remove and replace the render

3) Add flashing (expensive but important) Must be done at the same time as the render - 2 days work at most.

4) Remove and replace the flaunching. 2 days work at most.

Then see what happens in the attic and move on from there if necessary. Also, check reviews of builders, get their registered addresses and do everything in writing (email is best). Only pay once the work is done to your satisfaction. There should be no need for money up front.

2
In reply to PaulJepson:

“Doing the lead flashing, soakers and pans around a normal stack will be in the region of £500. “

By doing you mean supply fit and strip a scaffold, and weigh in your lead?

what labour rates have you in for the hour 

In reply to Frank the Husky:

£4700  your price never having seen the job  £1900 more  from the man on the ground not such a major difference  

In reply to Name Changed 34:

> £4700  your price never having seen the job  £1900 more  from the man on the ground not such a major difference  

What's your experience of taking down & rebuilding chimneys? How many have you done and how many dodgy builders in that field have you met who massively overcharge for simple jobs (like the guy you call the "man in the field")?

The price I mentioned for the recent job I did was for taking down a chimney and rebuilding it, which I made very clear. If I was just taking it down & capping it that'd be a far easier job and the overall price would be way less, likely in the region of £1000. At that point, even with the most expensive scaffolding the overall cost would be £2500, compared with your "man on the ground" charging £6600. The difference is £4100 which is a complete rip off and a very long way from being - as you put it - "not such a major difference".

4
In reply to Frank the Husky:

Good morning, to answer your question, none. However this is not stopping me understand realistic business costs including profit, or how to tender for work.

from the first poster :

(They have quotes to remove and completely rebuild the existing stack with a new cap and relining of the flue. )

your comment about the price differences of  £4100 “being a complete rip-off “ is in no way a like for like comparison. You do not rebuild, or line the flue, in the exemplar you sighted.

 I accepted that I have not removed a chimney, can you accept that 1) you are sucking through your teeth and pontificating on a job you have not seen 2) That you have no idea of access and moreover how big it is or the number of flues within. ?

Ps. It was man on the ground,  not “ in the field “ 

Post edited at 03:50
In reply to Name Changed 34:

In the OP, he doesn't mention rebuilding the chimney, he says the quote is for just removing the stack and capping it and lining. If I missed the bit where he said they are rebuilding it that that's a fair cop. Relining is £75-250/m plus the daily rate. That can be as expensive as you want to make it.

As to your points 1 & 2 - I'd agree up to a point. Bear in mind he says it's a 15-20 year old 2 story property with no exceptional or unusual issues regarding the chimney. To be suggesting a complete rebuild of what is effectively a new chimney is pretty unusual. Access has never, in my experience, been at all relevant as the scaffolding takes care of that. I'm always impressed by the high prices companies quote and my experience is that companies/tradesmen charge way over the odds in the vast majority of cases, often with average results. If I was the OP I would be doing exactly what I suggested to begin with - the simple (and therefore cheap) stuff. My bet is that those remedies will resolve the problems without paying through the nose for an unnecessary rebuild.

Merry Christmas!


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