This forum has helped me so much this year. I couldn't find this topic via search so I'd thought I'd start a new thread.

The builder put a cosmetic coating on the exterior foundation (1-2' from ground level up to the brick). It looks like concrete color paint (very thick)? Maybe a thin layer of concrete?.

Anyway, the coating has been slowly coming off in large chips/sheets over the years and now (6 years from new) is very weakly bonded in spots. It is making a mess of my landscaping around my home and also the bare foundation looks awful.

I'm looking to stop the flaking off of this coating and restore the cosmetic coating in a lasting way.

Any advice would be appreciated.

Cheers

 

Sounds like it could be stucco. Can you post some pictures?
http://www.doityourself.com/forum/el...-pictures.html

 

Ya, pics would help. If it's stucco, you'd need scrape off any loose and then restucco those areas. Painting the stucco should help it last longer.

 

I'll take some pics this evening and post ASAP.

 

Pictures:

 

That's stucco. Basically you'll trowel it on and then as it sets up take a brush to it to get the texture. I don't do much masonry work so you might want to post in the brick/masonry section of the forums to make sure you do it correctly.

 

Now that we know it's stucco, I'll move this thread.

 

In the top picture which is the foundation and which is the coating?

 

I can see the height difference on my monitor - the foundation is on the left and the coating on the right.

 

I doubt if you can stop the flaking. Best bet is to scrape off everything that is loose. If you are lucky it will all come off. Then you do not have an offset to deal with. Pressure wash everything or else use a 10% muriatic acid solution and scrub it with that then rinse it thoroughly with clean water or neutralize the acid with ammonia or a baking soda solution and rinse that very well. Whatever you use to retexture this will probably bond better and last a lot longer if you add some acrylic to the mix Acryl 60 or BASF WS Poly 1 are good ones there are others. Use a hopper sprayer to do this or a dash brush. You can spread it and float it. I think you get a nicer texture if you dash it. A dash brush is the old time poor man's sprayer.

 

Thanks. I'm definitely going to try and get all the old stucco off. I'm not sure if I want to re-stucco though. I have no experience and not a clue what to do. Would a masonary paint be ok? I'm looking to get a long lasting uniform gray color look (as opposed to the dirty white/black/gray look of the bare foundation). Not really interested in uniform texture.

 

I'd go with a good coating of Thoroseal, possibly with Acryl 60 as a bonding agent. We used thousands of gallons of the stuff on new bridge surfaces back in my DOT days, and it stuck like glue (and comes in colors). May not be available at Big Box stores, so a masonry supply place would be a good source. As others have said, proper surface prep is mandatory, or you'll be doing the job again in a few years.

 

I'm not very fond of masonry paint, basically it's just a cheap house paint. Latex house paint will hold up longer. For painting - use a masonry primer or exterior latex paint thinned about 5% as a primer. If the substrate is chalky - add 1 qt of Flood's EmulsaBond to each gallon of primer. Top coat with either a quality latex house paint or an elastromeric paint. Elastromeric paint has some waterproofing qualities and usually holds up well.

While I've heard good things about Thoroseal, I've never used it or to my knowledge been on a job where it was used..... maybe it's a regional thing.

 

When you get everything scraped and clean then use a Portland cement based product. Thoroseal is a good one. Use acrylic in your mix. There are proprietary materials that have a dry acrylic already in them. You can spray this with a hopper or use a dash brush. Some materials like Thoroseal can be applied by a brush by spreading them. Do what works. The most important things are get it clean and use acrylic.

I have had good luck making my own material for this. 1 part fine sand : 1 part Portland cement mixed with enough acrylic solution to make it do what you want. Like thick paint to paint it on with a brush or like pancake batter to spray it. The acrylic is mixed with water in the ratio of 3 water : 1 acrylic or as otherwise specified on the container.

Stir all of this up, let it set a few minutes then stir it again get the consistency right and put it on. A whitewash brush works well to paint it on. Don't try to spread it too tight, that is make it go too far. You can put on more than one coat and if you time it right you can even it out with a clean, damp brush after it takes up a little

 

I studied the picture a little more. I think some kind of Portland cement coating was put on over the dirty stucco foundation. Had the stucco been clean the coating would probably have bonded. On the other hand had the stucco been clean it might have looked good enough that no other coating would have been applied.

There might be mold or algae on the stucco, too so in addition use some bleach to clean it. I would use bleach, rinse, acid rinse and TSP and rinse then rinse again then put on a Portland cement based product and expect it to last the rest of my life. Or forty years which ever is longer.

 

In the first picture the left portion is bare foundation (ugly and rough). On the right is the cosmetic coating that is flaking off. The coating thickness is ~4-5mm average.

The second picture shows a flaked off piece of the cosmetic coating.

The coating looks and feels like very light and brittle cement.