Retro Fitting Movement Joints into Concrete Walls

[self builder 123]

Hi

We have been advised to have movement joints fitted into the walls on the house before it is rendered.

The walls in question are over 6m in length. The house is a timber frame construction with a standard dense 7N/sq.mm concrete block outer leaf.

I understand that there should be a movement joint every 6m along a straight wall and 3m from either an internal or external corner.

The roughcaster is going to cut down half way through the blocks with a Sthil saw before fitting the movement joint and then rendering.

I appreciate that the actual movement joint should have been a 10mm gap right through with frame ties either side in each course - not sure why the builder did not do this in the beginning ??

The house has been built for several years and no cracks have appeared, however I like the idea being suggested by the roughcaster.

I take it that there is no down side to this ?

Comments please !

 

[Shytalkz]

Use expamet (riblath) and render onto that. Render directly to blockwork is always prone to cracking. No need to be titting about cutting joints then.

 

[self builder 123]

Hi Shytalkz

You mean use the rib lath to cover all of the concrete walls and then render onto that ?

 

[Shytalkz]

Yep