Underlying boards showing through render - suggestions?

[Bitpipe]

6 hours ago, jack said:

Glad to hear they're taking responsibility.

 

Yes, their proactive nature has come as a relief - I've given them space to deal with it and stayed calm.

[Bitpipe]

So the problem went away over winter and has returned with the warm weather we're having.

 

Pinged them a note (we'd agreed to leave any action until spring) and their new thought is that warm air is getting trapped in the 25mm cavity between render board and exterior TF wall, causing the issue, so perhaps improving airflow in the cavity is something to investigate initially.

 

I'm a bit sceptical as in my mind the action of the sun on the face of the board will heat it up more than the air behind it. Also, the parapet roof alu cladding overhangs the render and sits on brackets to allow expansion, so far from airtight.

 

Anyway, will see where this idea goes...

 

 

 

 

[Bitpipe]

Another year on and we're getting closer to resolution.

 

I put a temp probe in the render cavity a few months ago and have been logging every minute so clearly saw that the temp inside fluctuates with the external temp, no build up.

 

Render company boss came out today along with Brendan from MBC (who co-incidentally was working on a build not 10 mins away from us) and looks like root cause is that the render battens hit and miss the wall studs behind the external weatherboard, so as the boards expand, they're pulling out the fixings on some battens.

 

Next step is to chop out the render on a small side wall and see for sure. Then the only remedy is to strip it back to the blue paper and start again!

 

Obviously they're less than delighted but have committed to do the right thing and the fact that they're back on site 3 1/2 years after doing the work is encouraging.

 

So, if you're rendering a timber frame house, make sure the render battens are aligned with the structural studs....

[scottishjohn]

7 minutes ago, Bitpipe said:

Obviously they're less than delighted but have committed to do the right thing and the fact that they're back on site 3 1/2 years after doing the work is encouraging.

 

So, if you're rendering a timber frame house, make sure the render battens are aligned with the structural studs....

glad to hear its getting sorted at last and as was predicted  its strip back and start again ..

all the woes you have had just confirms my thoughts that render on TF  is not the way I would go 

It would be cladding.

I don,t suppose they would convert it to that instead ,if you wanted?  

 it does show that the actual render is very  good + flexible as it has not fallen off in lumps ,

Edited June 27, 2019 by scottishjohn

[Bitpipe]

1 minute ago, scottishjohn said:

glad to hear its getting sorted at last and as was predicted  its strip back and start again ..

all the woes you have had just confirms my thoughts that render on TF  is not the way I would go 

It would be cladding.

I don,t suppose they would convert it to that instead ,if you wanted?  

 

No, I like the render finish and if the battens are correctly fixed to the underlying studs (which were marked) then there should have been no issue - an unfortunate oversight that will cost them a few £ but they're very professional and have never shirked from their responsibility.

[Mr Punter]

26 minutes ago, Bitpipe said:

make sure the render battens are aligned with the structural studs

 

Were they not clearly marked out with plastic tape stapled to the breather paper?

 

I can't think of many contractors who would undertake this. Is it just the one elevation or the whole thing?

[scottishjohn]

I certainly would be wanting to check the moisture content of all the wood behind this render panel -as soon as there is a hole to get at it 

just in case it is some other underlying problem .

 

[PaulQ123]

Has the problem been resolved?

Were the battens screwed or nailed?

Were the replacement boards EuroForm MgO boards or are they now using a cementitious board?

What are recommended screws and fixing centres for fixing boards?

What are the recommended joint gaps?

Were joints tapped with mesh

Were the joints filled in any way and what with?