Key smoothed bricks before rendering?

[andyrew1]

Hello

The area below our front step had been covered with cement render and painted and the paint extended onto some adjacent bricks.

My plan is to repoint/dub out, and then rerender the area with some lime as the faces and edges are damaged from the cement removal.

In some areas I used a grinder to take off the paint leaving quite a smooth surface.

Would it make sense to key the very smooth areas slightly before trying to render?

 

[a twig]

From what I can see of the photo - definitely not needed, no matter how careful you were with the grinder it won’t be as smooth as the original fired face, and that doesn’t need keying

 

[Lacan07]

Hello

The area below our front step had been covered with cement render and painted and the paint extended onto some adjacent bricks.

My plan is to repoint/dub out, and then rerender the area with some lime as the faces and edges are damaged from the cement removal.

In some areas I used a grinder to take off the paint leaving quite a smooth surface.

Would it make sense to key the very smooth areas slightly before trying to render?

View attachment 14346

Thats fine, no key required. the new repointing will provide suction anyway.

Traditionally when plastering over painted or smooth bricks that would hammer and chisel a couple of rough dents into each brick

 

[stuart45]

There's a number of different methods of achieving a good key for render. On new work it used to be a normal part of the job to rake out the joints. On some bricks there are keyed sides in the brick. Terracotta blocks go one better and have dovetail grooves for a key.
Otherwise, metal lathing can be fixed to the wall. This is especially important on really poor, friable walls. A splatterdash coat is another method. Using a bonding agent like SBR or PVA is popular, or roughing up the surface as Lacon07 said.
On a highly absorbent background you need to damp down the wall properly.

 

[andyrew1]

Thanks all, I'll put a few chips into the smoothest areas as suggested by Lacon07 even if it seems it might be bit overkill