Expansion joints or not in monocouche render

[nomisr]

Hi,

Having extended my detached bungalow on both sides I'm about to have it rendered in monocouche (http://monocouche.co.uk/). The contractor has recommended expansion joints where the extensions meet the original building, indicated by arrows on the drawing below. Is this strictly necessary as I'd rather have a nice continuous finish?

The total width of the section to the left is ~10m and the section to the right is ~14m. The original dwelling sits on 450 x 600 footings while the extensions are on 600 footings varying in depth from 1200 to 1800. The whole lot sits on Oxford clay.

Thanks in advance.

Nomis

Untitled

• nomisr
• 12 Dec 2014
• 1

 

[Micilin]

Of course, expansion joints would be sensible.

They are also called 'control joints' . You can't stop buildings moving, but you can try and control where the resulting cracks run, and disguise them.

Likely area to crack are where he says, also around doors and windows which is why we use a 500mm band of overlapped mesh in these areas if it is not a 'full mesh' job.

You can use integral expansion beads or stop beads and mastic. Use of mesh can ensure that the joints are in internal angles so less visible, if you have to move the joint.

He may also be using them to allow for day joints , so that he can stick protection onto the bead to protect the finished work, while applying the next area of render.

After all, you need a break somewhere, either at an external or internal arrice.

Sounds like good advice to me.

 

[nomisr]

Thanks Micilin for your thorough and very informative answer. Control joints it is then.

 

[stevethespreader]

Good advice from mic defo expansion joints if you don't have them you will almost def get a crack where new meets old better to have joints rather than cracks

 

[Micilin]

Thanks Micilin for your thorough and very informative answer. Control joints it is then.

That's okay - easy to answer when there is a sensible question!

Good luck with it.

 

[Micilin]

Good advice from mic defo expansion joints if you don't have them you will almost def get a crack where new meets old better to have joints rather than cracks

We are back on the same page, Steve

 

[stevethespreader]

Good advice from mic defo expansion joints if you don't have them you will almost def get a crack where new meets old better to have joints rather than cracks

We are back on the same page, Steve

yes expansion joints is a no brainer