concrete ceiling patch

[beddy]

The bonding of 30 years ago & today are totally different stuff. You used to be able turn the shovel upside down & gravity still wouldn't make it let go.
It's let me down a couple of times in recent years applied to ceiling repairs of an inch in thickness - You turn your back & the lot is on the floor.

for the task in question I would scratch coat it in Weber Rend aid, and apply the Limelite to it the next day.
I have used Rend aid onto smooth concrete (after shuttering was removed) and it ain't gonna fail ... trust me!

weber.rend aid - Weber

There you go. Its not designed to go on an inch thick. 2 half inch coats keyed in between wouldn't Budge I reckon

 

[carlos]

SBR slurry then render on a SBR modified render coat while the slurry is tacky. Key well and second coat the next day.

 

[johniosaif]

SBR slurry then render on a SBR modified render coat while the slurry is tacky. Key well and second coat the next day.

Sbr modified render coat ? Can you expand ?

 

[Pluto]

Sbr modified render coat ? Can you expand ?

Yes if @carlos eat as many doughnut as I eat today lol

 

[leebo02]

Yes if @carlos eat as many doughnut as I eat today lol

:RpS_lol:

 

[carlos]

SBR slurry then render on a SBR modified render coat while the slurry is tacky. Key well and second coat the next day.

Sbr modified render coat ? Can you expand ?

Yes mate Use SBR as the only additive in the render,
https://www.permagard.co.uk/media/uploads/SBR Bonding Additive Data Sheet.pdf

Worked well for us in the past when going over glazed bricks.