After reading your explanation, it seems I have received the wrong advice. I have spralling concrete on my bathroom ceiling and I was told to use putty. Another shop recommended using Davco k11 rapid plug. I have a 1kg white cement at hand. What should I use? I have already applied anti rust coating on the exposed bars.
spalling concrete, need to make mortar mix rather than just white cement. use 3 parts sand to 1 part cement. then patch over the exposed bars. its not easy work, you better get a handyman to do this if you no experience. you need to apply quite a lot of pressure when troweling/pressing in the cement or it will be weak.
that shop is recommending you a premixed rapid setting mortar mix (means already have sand mixed in with cement), good for sealing leaking walls and wet places.
most importantly, have you checked why your ceiling is spalling concrete? normally it means you have water leaking from above.
This post has been edited by diffyhelman2: Dec 26 2022, 10:23 PM
The actual label on the Davco tin doesn't have this description "non shrink grout cement". ...
That davco will work as it is a type of cement mortar mix that is used to seal leaking holes very quickly ( the cement hardens within five minutes). However it is expensive and you need a lot of it To patch your spalling cement since your rebar is visible.
Just call a contractor. Tell him/show him the video and tell him you want that kind of repair. But also ask him to check the roof above to make sure there is no water leaking.
scrap out all the surrounding paint, and any loose plaster, beginner can use putty if the patch of plaster that came out is not too thick (< 5mm). apply in thin layers as the first layer will likely have cracks after it dries. sponge it with a car wash hard sponge that is just damp to smoothen it and conceal any fine cracks after.
but to me, the problem looks like you might have a leak from above as the loose plaster is only at the edge of the ceiling/wall. touch the ceiling see if its damp after rain.
This post has been edited by diffyhelman2: Dec 27 2022, 02:20 PM
Unless the whole house is under renovation and the workman is always there, all repair work on minor ceiling spralling are completed in one visit. There is no luxury of time for the coating on the rebar to dry or the concrete to set. The contractor will just paint over and move to the next job. This is what I have heard from friends who hire contractor to fix their bathroom ceiling.
You are right. That Davco is 7X the price of white cement and putty. My first attempt to prepare the mix was too slow and the whole mixture turned into a rock before i could apply on the ceiling. Yes, it sets in five minutes. There was no time for proper skimming. I am using Davco now for the bathroom ceiling that has an exposed rebar.
The other cracked ceiling in the bedroom was thankfully just the plastered celing coming off. It wasn't damp. I patched it with putty.....will spread another layer of putty tomorrow before painting over with Vinelex and antimould paint the next day.
Good to hear that, normally i use davco type products to seal gaps in drains and joints where water is flowing, thus the need for a very quick setting mortar. The other use for that type of cement is to “hold” rebar or some other pieces of item i need to place on concrete before applying the main concrete. It sets so fast that you can use it like an extra pair of hands.
Dec 26 2022, 10:20 PM
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