patch in wall

[marsaday]

I have a circular patch in the wall near where the new stairs have gone in.

This needs filling with bonding and skimming.

BUT could i just use a sand/lime/cement mix instead and skim over that. I have a load of these left over, but will need to buy a new bag of bonding just for this small patch.

If i can do i need to score the mix after it has hardened ?

 

[NickB_99]

BUT could i just use a sand/lime/cement mix instead and skim over that. I have a load of these left over, but will need to buy a new bag of bonding just for this small patch.

If i can do i need to score the mix after it has hardened ?

I don't see why not, though will take longer.
Using sand/cement/lime will take longer to harden than bonding 'going off'.
I.e. you would need to apply the s/c/lime, score it for a better key, and then leave until the next day ideally. (You score whilst still wet, but firmed a bit).
I would scrim tape over the joint (as it's probably a different material than what's on the rest of your wall and may expand differently and crack the finish at a later date). I would then multi over the top. Depending on size of wall, whether I try to blend in or re-skim the whole wall.
Of course if not competent skimmer, you could consider easi-fill.

Though for the extra £5ish if you went with Bonding, you would get the job done in the same day, as it goes off quicker than s/c.

 

[Richard C]

Try & use whatever is there already i.e. if render base use render, if base plaster use a base plaster. As newbie99 says, different materials expand & contract at different rates & could mean you get cracks forming where the two meet. Fill the base out in two hits rather than slapping it all in there, less chance of cracking.

A little trick is to remove the layer of finish skim from the base around 30mm or so all around the patch, fill out the render/plaster repair flush with this, add a good dose of reinforcing tape where the base coats join, then skim out & finish flush. Blending Multi can be tricky if you’re inexperienced so you may need a little filler but don’t use too much water in an attempt to smooth it out or you’ll end up with a mushy mess between the two & it won’t adhere. I usually fill out repairs flush with the base & re-skim the entire wall, it’s the only real way of guaranteeing you won’t see the join.

 

[marsaday]

thanks for the info. reskimming the whole wall will be a pain, but it may need to be done.

i think i will go with bonding as i also have another patch to do which i forgot about.