what sort of ceiling paint

jrhartley

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I have a little problem with my ceiling- the exterior was treated some time ago, but the paint ins ide still keeps coming off- no visible damp,but the cotton woolly bits push the paint off, any ideas about what sort of paint to use, Im contemplating water based pool paint as nothing else seems to work (desperate measures)
 

reese_in_va

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We have the same problem with our painted, concrete roof.
The exterior paint gets a bubble, then the bubble fills with rain water and the water slowly leaches into the concrete. When the concrete is moist enough the paint eventually absorbes it and it flakes of, creating a dust like powder.
Overtime the bubbles on the roof get bigger and there is more moisture absorbed.
It doesn't take a lot of moisture either.
There are two ways I know of dealing with it.
First, is to re-paint the roof with elastomeric paint. This involves scrapping the old bubbles off. Manufactures recommend doing two coats, typically with-in hours of each other.
The other alternative is to rubberize your roof. This is more costly but in the long run will last longer, if installed properly.
 

jrhartley

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the actual outside has been doone with the specialised rubber paint....but the inside doesnt seem to want to know....been scraped and repainted three times now in six months
 

AlaninDR

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You might try drilling small holes in the ceiling to allow the concrete to vent. It was done on my south coast home years ago and worked well.
 

bob saunders

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MASONRY AND CONCRETE - If efflorescence or cement dust is present on masonry and concrete, it should be removed by etching with a 10% solution of muriatic (Hydrochloric acid) solution; wear protective goggles and rubber gloves. Flush off surface, after etching, with clean water and allow to dry.
On surfaces where muriatic acid cannot be used to neutralize the efflorescence, sand, scrape, and wire brush and coat with Masonry Conditioner before painting.
Prime with latex primer and allow to dry four hours before topcoating. Rough concrete and haydite blocks should be filled with Latex Block Filler. Allow to dry overnight before priming.

So in a nutshell clean, seal, prime, paint. None which will be any good if your roof leaks.
 

whirleybird

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Feb 27, 2006
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the actual outside has been doone with the specialised rubber paint....but the inside doesnt seem to want to know....been scraped and repainted three times now in six months

Could it be that there was too much salt in the sand that was used for the original plastering? I am told that this might cause the continuing problem.
 

Chip

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the actual outside has been doone with the specialised rubber paint....but the inside doesnt seem to want to know....been scraped and repainted three times now in six months

It sounds like you still have a leak somewhere. Check around the edges on the roof. If you have a tank on the roof it could be a like in the piping supplying it.

I had the same problem but after we sealed the roof and fixed some plumbing it all but went away. It still happens when it rains a lot and I think it is probably a downspout coming from the roof is not sealed good.
 

reese_in_va

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Whirleybird has a good point here, salt in the sand/ cement mixture. If there is salt present it will create efflorecence on a larger scale.
I would not recommend "drilling holes" to "vent the ceiling, this in itself does not make any sense to me and I can't image how this would resolve any problems with water retention.
To fix the problem you MUST repair where it originates from, this is the outside/ exterior of your roof.
jr, I know you said it has been painted with "specialised rubber paint", this is elastomeric paint. I would have to assume that the paint is not doing its job properly, or that it was never properly painted correctly. You can't paint under direct sunlight (it cures too fast), you can't just simply roll it on quick (this doesn't allow for a thick consistant coat), you can't walk on it too much right after its been painted (this is usually when problems occur to putting the second coat on, and again manufactures recommendation is ...I think...3-4 hours after the first coat).
Take a look yourself up on the roof, if you can and look very closely to the existing "rubberized" paint. Look for tiny bubbles in the paint or "hairline" cracks in the paint.
Your will be wasting your time and materials redoing the interior, without correcting the problem at its source.
 

Spicedwine

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MASONRY AND CONCRETE - If efflorescence or cement dust is present on masonry and concrete, it should be removed by etching with a 10% solution of muriatic (Hydrochloric acid) solution; wear protective goggles and rubber gloves. Flush off surface, after etching, with clean water and allow to dry.
On surfaces where muriatic acid cannot be used to neutralize the efflorescence, sand, scrape, and wire brush and coat with Masonry Conditioner before painting.
Prime with latex primer and allow to dry four hours before topcoating. Rough concrete and haydite blocks should be filled with Latex Block Filler. Allow to dry overnight before priming.

So in a nutshell clean, seal, prime, paint. None which will be any good if your roof leaks.

That is exactly the only way I know how to deal with your difficulty. We had much the same trouble. No roof leak anymore!!! But clean, seal, prime, paint.... we primed several times with much drying time between and it seems to have solved it for us. Good luck!!
 

AlaninDR

Mr. Chunky Skin
Dec 17, 2002
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I would not recommend "drilling holes" to "vent the ceiling, this in itself does not make any sense to me and I can't image how this would resolve any problems with water retention.
To fix the problem you MUST repair where it originates from, this is the outside/ exterior of your roof.

As I said, drill holes in the ceiling. I didn't say drill holes in the roof. One is inside, one is outside. Obviously the water entrance must be addressed first. But once the water is inside the walls, ceiling or any other structure, it has to be given a way out. That's one of the reasons paint blisters and bubbles, because of water exiting. If ambient humidity in the ceiling is equal to the outside humidity, there is little problem. The problem is when the humidity/moisture is higher in the concrete than the surrounding area. All forces tend toward equalization. Drilling holes in the ceiling worked for me.
 
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J D Sauser

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It never leads to a satisfying result to paint masonry on both sides, especially masonry facing the outside on one side. That's why usually an interior insulation or "lining wall" should bear the inner finish. Here, these rules don't find much observation of course, even when the local climate would call for special observance. Masonry needs to be able to breath. If you have a rubber (sealant) finish on the exterior, the wall or concrete roof will try to breath towards the other -in this case, the inner- side where the lighter finish will give way.
There are also some known and well documented inherent health issues related to homes which have been made too moisture and thus in a sense almost air tight. Mold and paint prematurely loosing it's bond to wall, would only be one visual testimony of not only and excess of humidity but lack of aeration.

My suggestion to you JR, if this is your home and you plan to keep it as such for some time, is that once you are certain you don't have any physical leaks, you'd consider have a lining installed at 1 to 2 inches of distance of the concrete. This can be quite decorative using wood panels, platane leaf sheets, or just a drywall or laminate of some sort. This may also help to keep your home cooler.


... J-D.
 
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Chip

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It never leads to a satisfying result to paint masonry on both sides, especially masonry facing the outside on one side. That's why usually an interior insulation or "lining wall" should bear the inner finish. Here, these rules don't find much observation of course, even when the local climate would call for special observance. Masonry needs to be able to breath. If you have a rubber (sealant) finish on the exterior, the wall or concrete roof will try to breath towards the other -in this case, the inner- side where the lighter finish will give way.
There are also some known and well documented inherent health issues related to homes which have been made too moisture and thus in a sense almost air tight. Mold and paint prematurely loosing it's bond to wall, would only be one visual testimony of not only and excess of humidity but lack of aeration.

My suggestion to you JR, if this is your home and you plan to keep it as such for some time, is that once you are certain you don't have any physical leaks, you'd consider have a lining installed at 1 to 2 inches of distance of the concrete. This can be quite decorative using wood panels, platane leaf sheets, or just a drywall or laminate of some sort. This may also help to keep your home cooler.


... J-D.

With all due respect JD, what you have written is correct to some degree, but the problem with jr's house is certainly not a breathing issue as he noted they have painted the house three times in six months. He has a rainwater or plumbing leak.
 

J D Sauser

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With all due respect JD, what you have written is correct to some degree, but the problem with jr's house is certainly not a breathing issue as he noted they have painted the house three times in six months. He has a rainwater or plumbing leak.

Thanks for pointing that out to me, Chip.
It was not what I understood from his opening post:

I have a little problem with my ceiling- the exterior was treated some time ago, but the paint ins ide still keeps coming off- no visible damp,but the cotton woolly bits push the paint off, any ideas about what sort of paint to use, Im contemplating water based pool paint as nothing else seems to work (desperate measures)

I don't know JR's home, so my answer was a generic one, based on the general question of what paint to use on the interior (ceiling) of a concrete roof which I am led to understand had been sealed on the outside.
As I mentioned, any cure or the finishing issue would have to be preceded by making sure there are no more leaks.

J D Sauser said:
... is that once you are certain you don't have any physical leaks,...

If now the issue I failed to recognize has turned out to be plumbing and roof leaks... no sense to talk about inner finishes and aeration until that has been solved.

Thanks for pointing that out to me, Chip! ... J-D.
 

jrhartley

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I wonder why they dont make concrete in colours other then grey, then I wouldnt need to paint it at all
 

Black Dog

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[QUOTE = jrhartley; 794,484] I wonder why they dont make concrete in colors other then gray, then I wouldnt need to paint it at all [/ QUOTE]

There are lots of shades of grey though! and they say "grey is the colour of kings" well actually they don't say that, I just made it up to make you feel better! :bunny:
 

Black Dog

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And why is this site changing my correct English spelling into dodgy American spelling?

No offence to anyone American!
 
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jrhartley

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elephant grey was very popular in the 60,s -teamed with tangerine ,yellow and a black ceiling,my father had some strange decorating idea
 

Black Dog

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And why is this site changing my correct English spelling into dodgy American spelling?

No offence to anyone American!

Hey, I just realised that I had the google website translator on and it was changing spellings grey = gray and colour = color. Now I've turned it off and all is well with the world!!!!
 

J D Sauser

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I wonder why they dont make concrete in colours other then grey, then I wouldnt need to paint it at all

As already responded by other forumites, yes, concrete can be tinted from gray or tinted from "white" cement. The issue however is, that white cement has much less strength than normal gray cement. Also color additives to gray cement have shown to affect the resulting concrete's strength.

It has been suggested that you might or do have a plumbing issue. Given that we are talking about your poured roof (?), this is something which, if it's true, would have me quite concerned. These poured roofs usually don't have the thickness to accommodate pipes buried in them without affecting their strength.

... J-D.