Repairing render

[ntl142]

I've got a small region of boss render, adjacent to a downpipe. The pipe used to leak from halfway up and was blocked below ground, but both are now fixed. I suspect this is why the render has become detached. It's a localised area, around the corner of the wall, probably covering about 1 sq ft. I'm aware I might end up chasing it a bit more than that, but I'm feeling optimistic. Photo attached.

I can chip it all off in this area, clean it up, and give it some texture for the new stuff to key on to, but what is the stuff I need to buy to put back on? It's a 1905 end terrace in an old Scottish mining village. I assume it's lime mortar but don't know for sure. Does this influence what I need to buy?

Once I've put the new stuff on, can I paint white straight on top, or do I need to leave it to dry for a few weeks and then prime it before painting?

Thanks.

 

[KenGMac]

ntl142, good evening.

Must admit if it were me I would leave well alone, why?

Because the crack as is at present is very small, if you proceed and undertook any repair that "Patch" would be visible, even once painted.

Ken

 

[ntl142]

The crack is small, yes, but the whole section of render below it is hollow. With the proximity to the ground, and downpipe, it is at more risk than usual of getting water behind it and spalling off with frost. That's fine if it stays in that area, but do you think it would have the risk of water creeping up behind it and causing it to spall off progressively further and further up the wall? Winter is cold up here... Thanks.

 

[ntl142]

Great, thanks. I'm planning on repainting the front of the house so I'll plan in a 2-3 drying time.

Still got the question of what do I need to buy to actually repair it with. Something like this? Doesn't seem quite right.

https://www.sandtex.co.uk/products/sandtex-ready-mixed-masonry-filler/

Lime mortar instead?

 

[KenGMac]

ntl142, good evening.

The roughcast render appears to be what is called [up here in the far frozen north] a Wet Dash

The original pebbles were mixed with the cement and sand then "thrown" on to the wall, paint was next.

How about you consider trying to get some liquid glue in behind the boss area of roughcast? you could water down some external water proof glue and using an empty squeejee bottle introduce the mix into the crack, you can assist this process by boring a small say 5. mm hole or holes into the crack to allow the glue an entry point??

As an aside? how long has that crack been there [that you are aware of??]

Ken