Gable end water ingress & damp following re-pointing - can the chimney liner be the cause?

dpetherick

Help! I will try and keep a long story short.

• Bought a ground floor flat in Scotland & the gable end rendering needed completely replacing.
• We (the 4 flat owners) commissoned a recommended builder to do the work in 2019
• He suggested re-pointing rather than re-rendering and we didn't know any different so agreed
• The first Autumn/winter I had significant water ingress (1 ltire collected) through the door frame in the gable end and eventually damp appearing in adjacent bedroom
• Long saga since because of needing to wait for the 'perfect storm' to test. Builder couldn't suggest anythign and says used waterproofing mixed in the cement used for pointing.
• Last year we had the chimney stack completely stripped, re-rendered, new flashing, new ridge tiles, new chimney pot. Got through last winter with just a few drops but a storm a couple of weeks ago caused same amount of initial ingress.
• There was no sign of internal damp or leaks before this work was done
• It seems to me that the pointing just absorbs water like a sponge! Rainfall this October is a lot higher than last year. My theory is that is just seeps through the pointing and with consistent rain reaches saturation point.
• Several other 'experts' have said that the pointing is shoddy work (the wall should have been left flat, not lumpy and bumpy) and it should have been re-rendered due to the walls position and the prevailing weather. The buidler is local so would have expected him to know this.
• All that has been half-heartedly suggested by the builder so far is waterproofing or painting
• I raised the issue again this week and reminded him of his 10 year guarantee and asked what he intends doing to identify and rectify the problem
• He has replied this morning saying he advised fitting a chimney liner to the one active chimney before he did any work and that this is the cause of the ingress. This is news to us! And surely there would have been a problem before the render was removed if this is the case?

So, to my question!  Can the fact that there isn't a liner cause water ingress, bearing in mind the recent works on the chimney? Many thanks, Dawn 

FreeBear

Looks like you have solid stone walls there. Slapping a waterproofing compound on is not going to do much, and painting won't cure water ingress either. If this is indeed a solid (rubble filled ?) wall, a lime mortar would have been preferable to a cement based one. That aside, I doubt water ingress through the wall is the problem.

If there is a problem with water getting in through the chimney, fitting a liner isn't going to cure anything... With a new pot being fitted, the flaunching will have been checked & repaired as required (if the contractor did a proper job).

In your shoes, I'd get a decent roofer out to take a look - The amount of water you are collecting suggests a roofing problem rather than an issue with the walls.

stuart45

I can't see the pointing properly from the photo, but I guess the other builders are probably talking about the joints being made flush with a lime mortar. 
Even with flush joints in a lime mortar, a solid wall can allow moisture through when subjected to continuous driving rain.
I'm these cases a lime render with a shelter cost is probably the best. 
Roughcast seems to be popular in Scotland.

dpetherick

stuart45 said:

I can't see the pointing properly from the photo, but I guess the other builders are probably talking about the joints being made flush with a lime mortar. 
Even with flush joints in a lime mortar, a solid wall can allow moisture through when subjected to continuous driving rain.
I'm these cases a lime render with a shelter cost is probably the best. 
Roughcast seems to be popular in Scotland.

Thanks Stuart. I asked whether they would be using a lime mortar as I knew this would be best and got fobbed off with some reply which sounded plausible. I wasn't involved in the initial requests out to potential builders to do the work and with hindsight we should have stipulated a lot more.  
This builder was commissioned to remove the old render/roughcasting and replace and then he suggested pointing. We didn't realise the risks of not doing this  

dpetherick

FreeBear said:

Looks like you have solid stone walls there. Slapping a waterproofing compound on is not going to do much, and painting won't cure water ingress either. If this is indeed a solid (rubble filled ?) wall, a lime mortar would have been preferable to a cement based one. That aside, I doubt water ingress through the wall is the problem.

If there is a problem with water getting in through the chimney, fitting a liner isn't going to cure anything... With a new pot being fitted, the flaunching will have been checked & repaired as required (if the contractor did a proper job).

In your shoes, I'd get a decent roofer out to take a look - The amount of water you are collecting suggests a roofing problem rather than an issue with the walls.

Hi, Many thanks for replying.
It is a stone wall (built in 1850). I'm not sure whether it would have intentionally been rubble filled but suspect that there is not quite a bit fallen down within the wall and that this is now wet   Thanks for confirming my thoughts about the liner, I was fairly sure that this is a red herring! 
We are confident that the chimney contractor did a good job, he has an excellent reputation. 
Getting someone to re-check the roof sounds like a good way forward, thank you