Render cracks

[TeaTime]

A colleague of mine has asked about the cracks in his conservatory wall.

He believes it a breeze block wall with render and pea shingle. It has a crack approximately 1/4" wide. He has heard that there is some sort of epoxy resin / mastic that can be used to fill the gap. Rather than chasing it right out and starting again.

Can anyone suggest what he needs to do to repair this?

 

[theprinceofdarkness]

Need more facts, is the side wall pulling away from the house? Dropping away from the house? Some of these DIY conservatories are built on insubstantial foundations, so filling the cracks will just give a few more years until that drops out as well.
Not like another poster on this forum who had a underground drain leak, causing a seven feet earth retaining wall to bow?
Frank

 

[TeaTime]

As far as he is aware, there is no movement obvious apart from the crack. Foundations seem to be sound.

If I need to provide additional details, please let me know what else I need to tell you.

 

[theprinceofdarkness]

As neither render or blocks are elastic, some thing has moved to open up a crack. Most subsidence cracks are wider at one end compared to the other. The widest part is on the outside of the bend. So for instance if the crack is 5mm at the top and it goes down to a hairline at the bottom, one side of the crack is "bending downwards", i.e. that half of the foundations have dropped. If the crack is the same width at the top and bottom of the building, then one half is drifting away from the other half.
Frank

 

[TeaTime]

Right, I have some more information.

It is actually on the back wall of the flat room extention i.e. outward facing wall not connected to the rest of the house, just the other two sides of the extension.

Crack runs from the room, down the wall, down the side of the window and to where the waste pipe exits the wall.

Thanks for the information so far by the way