Cracks in rendering

[Gaygle]

Hi all,

Just bought a new house which is around 7 years old.

It is timber framed and has rendering over it, with brick at the bottom of the house. I've noticed that there are quite a lot of hairline cracks over the rendering on the front and side of the house.

Now, I don't know a lot about building etc, but can these be repaired? Most of them are very hairline in that you can see them, but you couldn't really fit anything in between them, but there is a vertical one on the corner of the house which is around the thickness of a credit card.

The worst ones (only 2):
http://imgur.com/P80F4eH
http://imgur.com/phT1g2d

The medium ones(about 4):
http://imgur.com/3Al7uPB

The minor ones (15 or so):
http://imgur.com/u3JYrgJ

 

[Derek W]

do you have any movement joints fitted to the external walls anywhere? (10 mm gap filled with mastic running top to bottom of the wall).

 

[Maccapacca]

Timber frames move, settle and shrink. I'm surprised they rendered it. Not a very good choice of construction methods.

 

[Derek W]

Timber frames move, settle and shrink. I'm surprised they rendered it. Not a very good choice of construction methods.

Done properly there's nothing wrong with that method

 

[lsg1r]

not 100% on this but don't new builds have a 'warranty' of 10 years (could be wrong on number of years)... this might fall under that although not sure if thats transferred to new owners etc

 

[Maccapacca]

Done properly there's nothing wrong with that method

Obvious statement is obvious.


Daft combination of building methods. To make it work properly would require many ugly movement joints and still won't guarantee not cracking.


Building warranties would only call that settlement and shrinkage I doubt you'd have much joy with claiming.

Most insurance firms won't look at a claim unless you can get a finger in a crack.

 

[Derek W]

Obvious statement is obvious.

Might be obvious but at least its not daft like the below statement.

Daft combination of building methods. To make it work properly would require many ugly movement joints and still won't guarantee not cracking.

Its a tried and tested method up this way and out of all the houses we've done I've only known one to have an issue with a crack appearing.

 

[Gaygle]

do you have any movement joints fitted to the external walls anywhere? (10 mm gap filled with mastic running top to bottom of the wall).

Nope, not that i can see. I'm guessing that allows for and absorbs small movement without cracking the solid rendering?

Timber frames move, settle and shrink. I'm surprised they rendered it. Not a very good choice of construction methods.

So do all houses when they're new tbh. It's a cottage style so the only real option tbh.

Done properly there's nothing wrong with that method

I agree - think it may have been rushed/done by idiots. TBH though, the cracks aren't terminal, there is only a couple of bigger ones, but the vast majority are such small/hairline cracks you couldn't even fit anything in between them.

not 100% on this but don't new builds have a 'warranty' of 10 years (could be wrong on number of years)... this might fall under that although not sure if thats transferred to new owners etc

If covered by an insurance policy like NHBC/Zurich etc, but this was covered by an architects certificate instead, which only lasts for 6 years... and 6 years was up in 5 months ago I'm not too bothered though, from hearing from other people, architects/insurance companies only get involved when there is serious structural defects. They would in all likelihood dismiss mine as just settling minor cracking.

Derek, you seem to know about this sort of stuff. Is it possible for a builder/renderer to remove a small amount of rendering and repair the section? There is one corner of the house about about 1.5 metres tall (Z axis), and 20cm on the X and Y axis of the corner which looks as though it could fall in the future.

 

[Derek W]

Nope, not that i can see. I'm guessing that allows for and absorbs small movement without cracking the solid rendering?

Essentially yes it does. Typically when i do drawings we have a covering note that movement joints should be fitted in external blockwork (or brickwork in this case although it may just be a brick basecourse!) every six metres.

Derek, you seem to know about this sort of stuff. Is it possible for a builder/renderer to remove a small amount of rendering and repair the section? There is one corner of the house about about 1.5 metres tall (Z axis), and 20cm on the X and Y axis of the corner which looks as though it could fall in the future.

This one is a yes / no answer. A builder / renderer will be able to remove a patch and repair it, however it would be near impossible to match the new render with the existing without it looking 'patchy'. They could match the pigment easily enough but with the 'weathering' that the existing stuff has taken, it would stand out like a sore thumb.

 

[the_r_sole]

something I've discovered recently on a job trying to avoid movement joints...
With blockwork leafs you need to have mjs every 6m but with a brickwork leaf you can get up to ~11m (according to the engineer certifying it anyway!)