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View Full Version : How do I apply the final finish (concrete wall) ?


mrfeetman
Sep 19, 2008, 02:38 PM
Hi guys , I am loving this forum so much its becoming difficult to stay away. Anyway , a few weeks ago I built a concrete brick wall , following instructions from a masonry book and it turned out pretty good : problem is I don't know how to mix or apply that smooth white looking finnish that the masons usually put on after plastering. Question : can anyone tell me how to create the finish mix and what the proportions are for the ingredients, all I know is there is suppose to be some portland cement, lime and sand, that's it. ANY help would be appreciated, thanks. Ps I tried to find the info in some masonry books that I have, can't find anything on it.

ballengerb1
Sep 21, 2008, 06:34 PM
Are you trying to describe stucco or parge? That ius the smooth white finish I know of.

mrfeetman
Sep 24, 2008, 12:38 PM
Are you trying to describe stucco or parge? That ius the smooth white finish I know of.

Hi ballengerb1, sorry it took so long to get back but I have never heard the term parge before so I had to do some checking. I live in the Bahamas and from what I've found out "parge" is what we refer to as " browning ". As far as the difference in the mixtures I think the stucco best describes what I am looking for according to what I've found out. Thanks for the response bellengerb1.

Gerald Ebbuts
Dec 31, 2008, 01:58 PM
I spent 10 years in the masonry trade here in Canada. We "parge" our concrete walls we parge our masnonry block walls also. This is done to make it look nice and also provide a better seel.

We used a mixture of 1/2 part type n and 1/2 part portland cement, then three parts masonry sand. Added enough water to make its spreadability somewhat between peanut butter and ketchup.

You do not want to do this on a blazing hot day, shade is helpful to allow it to dry slowly in order to prevent cracking.
We would first clean and wet the blocks or concrete and allow to soak in a bit. Sometimes we would cover the surface with a white glue like construction adhesive meant for concrete, let it get tacky then take a finsihing metal trowel starting at the bottom at the corner spreading upwards lay on a coat as about a foot and a half wide area at a time. Make it as smooth as possible and hopefully by the time you are done you can go back to the beginning taking a large sponge and rub the coating to get a sand finish effect.
You can't use the sponge if the coating hasn't hardened up enough so sometimes you have to wait depending on the weather.
Rub the sponge in circular motions in order to get the trowel marks out and a nice sandy finish. Wet and ring out the sponge frequently in a bucket of water.

21boat
Jan 1, 2009, 04:52 AM
Hi 32 year Lancaster Pa. mason here. The skinny on pargeing. If this is concrete block and clean block. And if you are going to "parge" /stucco it. You will be putting on two coats of mortar. First wet the wall slightly before you start. Use a concrete finish trowel and apply the first coat about 3/8 or less thick. As it sets up you need to 'scratch it" There is a scratch comb that is about 12 inches wide metal tangs. Looks like a very small grass rake you can buy at a masonry store. OR cheap, take a 2X 4about 12 inches long and pound some nails all the way through it and now "rake" Let part of the wall dry out and then Rake over the now stiff coat. Don't let the mortar dry out too much if is in the sun. The dry out is little shrink cracks.
Now 24 hrs later take your trowel and lightly scrape down the dry scratched cost. Mix up more mortar dampen the scratch coat and apply another coat and try to keep it flat and smooth. Now here is the big decision. Your finish of what you like. After the finial coat is partially dry get a bucket of water and a horse hair brush and wet totally shake it out and now half swirl the damp coat you just put on don't rush it too much wet on wall and coat will run or peel of right in front of you. Another finish is use a nice good sponge instead of brush.Or Find an old cushion and the inside is a smooth foam and cut that ti use. You can go over some brushed area again but be careful it can change the color because it brings out more lime. When you use any of these techniques re rinse very often to re brush wall as you go on. Now the mix choice. If you want to use Portland type N or S this will be in a 92 pound bag. Now the lime and sand I ratio 1 bag of Portland to half bag of lime to 32 big shovels of sand. Or break it down 1/2 Portland 1/4 lime 16 sand. Now If you want it easier at the masonry supply house where you get the cements you can get Keystone mortar bag this has the lime in it one bag to 200lb of sand 200lb of sand is ruffly 16 big shovels of sand. P.S. If this is a clay fired brick wall a galv. Stucco wire is needed for stratch coat.
Gerald 1/2 part type N 1/2 part Portland is the exact thing Portland is a type S or N. the S is for high strength and you did not mentioned Lime just sand and Portland bad mix. Sorry big guy. Bahama man do they use a blue "Bull Bond" to coat the bare wall first and then mareleena plaster with Portland mix for the finish I do conc In Puerto Rico and that's what the use Sorry guys for the long post I don't do short well P.S. the reason for the two coats is when the wall gets wet in rain you won't see the block joints show up as much as one coat. The mortar joints in the laid block stays wet longer and shows shrow more with one coat.

Signed 21 boat

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mrfeetman
Jan 7, 2009, 07:42 PM
Hello guys , been really caught up in the holiday festivity and I've just manage to get back to this forum. Thank you Gerald Ebbuts and 21boat I've read both post and found valuable information in both answers certainly made my job easier . By the way 21boat I've seen masons use a blue substance usually comes in a gallon bottle on concrete walls mainly when they are adding an addition onto an existing structure .(I don't know what its call) Once again thank you guys I find these post very helpful.

21boat
Jan 7, 2009, 08:01 PM
blue substance
Its called Bull Bond.

Bull Bond Manufacturing Corp
35 Rio Canas Indus Park, Caguas, PR 00725
Contact Phone: (787) 653-4900
URL (web address):
Business Category: Paints And Allied Products, Nec in Caguas, PR
Industry (SIC): Paints, Varnishes, Lacquers, Enamels, and Allied Products
http://www.manta.com/coms2/dnbcompany_g9gv7d

Where have you seen this what geo are you? Puerto Rico in they use this like candy. I laugh because they put this on New block walls and its crazy to say the least New block walls are pores and ruff for the mortar to stick good. Most all of the crib uses it and I Imagine in the U.S. where the Mexicans work too. It's a type of glue to bond old to knew plaster / Portland mix to walls. I ve been around this for 22 years going to Puerto Rico where I do Construction in the winter What they haven't figured out is it should only be used on old ceilings or old plaster walls and it doesn't last. I patched a ceiling In P.R. at least 9 times over the years, and no its not me it's the product. It doesn't even vary much in temp( No freezing) I finally fiberglassed the patch and it works great. We did the fiberglass on a newly built exterior concrete 3 story hotel bed and breakfast in P.R. The blue stuff should never be used outside. It should never be used unless you can't galv wire up and stucco. It should never be used where temperature changes too much and or freezes. In P.R. they have to use it outside because the galv. Wire would rust out from the salt moisture. There concrete eats out the rebar because of the salt in that. All bar should be coated before pour. Here in the states where I'm its parge new wall or galv wire over old walls and coat.

Signed 21 Boat

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