Expansion joint in block wall

[jmhill]

Hi

I’m building a retaining wall in my garden.

There are already similar walls in the garden that have been constructed from 140mm blocks laid flat and rendered with sand & cement.

The walls have been in place for around 20 years and show no signs of cracking or movement.

I have decided to copy this formula and am building a 1.2m high 9 m section of wall between two of the existing walls.

My question is, the wall I am building apparently should have an expansion joint however none have been inserted in the existing walls of similar dimensions. Are expansion joints just best practice or are they essential. After all there are no expansion joints in my house?

As a diy’er I want to keep the job as simple as possible but I of course I want to make the wall long lasting and structurally sound.

Thanks in advance.

Jon

 

[^woody^]

Is this the wall you are joining to an existing wall that would need a movement joint (not expansion joint) not because there will be expansion, but purely because the new wall will move and it will crack render where the two join?

 

[Leofric]

The provision of movement joints depend on the lengths of walls. ( or possibly where joining new to existing ) Retaining walls also require weep holes at the base of the wall to prevent water pressure building up behind the wall.