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Concrete calthemite

Hey guys - I asked the below question on here last week and had some fantastic help, I've just come across this online which I'm almost certain is the issue I have been having. https://en.wikipedia.org/wiki/Calthemite

Just wondering if anyone has any direct experience with this and if my POA below will need to change at all, I'm guessing I'll have to get upstairs on to the neighbours balcony and look at sealing the concrete ceiling and look at examine it for any cracks 360 degrees.

- cover the railings to stop further damage short term.
- wait for the weather to improve a bit.
- have a look at upstairs balcony to see if they have a crack or if it's in disrepair.
- strip the ceiling back to as close to bare concrete as possible and leave it to try out for a bit.
- paint with a primer and then two coats of weathershield

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Outdoor Paint Dripping
Hey guys - any help or guidance gratefully received and apologies about the length of the post.

First time home owner here, we have a small outdoor balcony with (what I think) is a concrete ceiling with another balcony directly above, the balcony has thick black metal railings.

When we moved in, areas of the thick black metal railings were eroded and exposed so I painted them with decent quality hammerite metal paint and it seemed to have done the job, unfortunately it highlighted that a chemical like substance (that appeared almost like thin candle wax) was dripping from the ceiling on to the areas where the railing were most exposed and eroded whenever it rained leading me to conclude that the white paint that was used on the underside of the concrete ceiling was the wrong sort of paint and it was causing the damage - although the ceiling is undercover, it is quite exposed and the wind blows rain in, I was thinking maybe whoever painted it last (many years ago) used the wrong sort of paint.

As it's been pretty wet here the chemical substance was dripping down on to my newly painted railings so I wanted to get it sorted ASAP, I bought some white masonry paint that was cheap but had good reviews and got it up on the ceiling when it was pretty cold (about 6 degrees celsius) and there was still some moisture in the air.

It has rained a lot since and the dripping is even worse than before and the paint is visibly bulging in areas with what appears to be damp trapped behind it.

My next move was going to be wait for a good dry period and put on some Pliolite Based Masonry Paint as people online are saying it's the stuff to use but am wondering if I need to remove the previous paint layers before or somehow try to remove the trapped moisture?

4 Answers from MyBuilder Painters & Decorators

Best Answer

If it is the calcium from the rain and concrete just wait till the weather is better before you proceed with your specification as above.

2020-02-27T14:00:03+00:00

Answered 27th Feb 2020

from your description as an overhanging concrete balcony I can only assume that water is hitting the above concrete balcony overhang and running off/ dripping onto your as such exterior ceiling which is causing this build up of these droplets.
I would first investigate the above balcony/ floor to see if water is draining off or creating a puddle, if it's not raining you can test with bucket of water. if above is draining correctly then it's back to your external ceiling to see how and where droplets are forming.
You could possibly create a small over hang on the very edge of your concrete ceiling which would be built to overhang your balcony railings, use maybe a 1inch pvc bead to sit on the very edge of your ceiling to stop water running into the center of your ceiling.
as for paint, masonry paint is no good for any external area unless adequately sealed, I would suggest any OIL based undercoat to seal, for this area I suggest you remove all/as much paint as possible allow to fully dry then apply an oil based undercoat x 2 coats before finishing coat.

2020-03-05T22:30:02+00:00

Answered 5th Mar 2020

I would there's crack on the floor of the the balcony above until that's sorted there is not much you can do

2020-03-14T16:30:03+00:00

Answered 14th Mar 2020

Yes wait for it to dry out firstly if you can get in contact with your upstairs neighbour get t if the crack is up stairs aswell it should be grouped or filled with a waterproof but flexible cement grouting and sealed to stop water getting into it from above then you may be able to make good a coat it up with two coats of weather shield or other masonry paint main reason for doing it's a more permanent solution rather that patch and potch and filling and painting for ever more

2020-03-18T19:30:03+00:00

Answered 18th Mar 2020

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