Walt Smith wrote: > My foundation is a cinder/concrete block with some layer of > plaster or cement put about a 3/4inch layer covering > it externally all around. A small section came off about > a casement window, about 10 x 10 inches or so. > > What do you recommend to use to patch ? Basically a 1-3 mix of cement to sand. I think HD or Lowes will have a smallish bag of that which they will call: mortar mix. Ya do two coats. 1- scrape or wire brush exisiting patch area surface down to good material. (no loose particles and NO dust) You got a pan about 12 x 12 ? A paint roller-pan will work fine. mix up enough mortar to fill the patch 1/2 way to the final finish. Add water till the stuff will settle down into a cow flop. It should pile up but not with jagged edges. (chunks) YOU CAN ALWAYS ADD MORE WATER! and will be. The trick here is to get this stuff to bond to the existing crap. So take a crappy paint brush , stick it in some water , and sling it into the pan. The water will settle into puddles. stick the brush into these puddles and swish it around to soak up some stuff. Then sling this against the patch. The stuff will fly off into the patch and should stick pretty good. I guess what happens is that the existing surface will suck the water out of the stuff and the cement with it into the cracks and crevices. The kinetic energy of the sling helps to drives it in as well. Important: At each one of these test the bond by sticking the brush into what you just slung and move it. If the stuff flakes off, throw it back in the pan and get some more watery stuff and try it again. Eventually it will get wet and bond. Now keep doing that until the whole thing is coated pretty well. Next take a cement trowel (like the diamond shaped things) or you can use a spackle knife and smear more stuff onto the area until it is 1/2 way full. Try to stick to a smear and not a float. A smear will have on edge against the cement and the other in the air. A float action is where you have the blade flat on the surface and it is like sucked to it. When this happens it will suck the cement off the wall! Air molecules in the block will expand and hold the cement away! Hopefully the block will suck the water out fast enough so that the cement will not flow down the wall which can be problem it th block is damp. If the block is real damp just smear the un-thinned cement directly on it instead of the water/brush technique. Anyhow when the cement is no longer runny but before it's too dry you want to "scratch" it. They make a scratching comb for this which is like a wide pic. You know , a fro comb , for the afro hairstyle. - got a handle like a paint brush and long teeth. If you have one around from your Starsky and Hutch days you can use that but it may roughen the plastic and ruin the collectors value. Right-on Just use a dinner fork. So you take the scratching comb and just drag it across the surface one way for the entire surface and then at 90 degrees. So should have a cris-cross of scratches that are about 1/8 inch deep or so. The second coat can be done as soon as that gets fairly hard or you can wait forever. Well you can't wait forever because that will never come , but you can wait... hmm wait , don't wait , , , , What you can do is recoat any time in the future that you want. The scratches will help provide the next bond. Now by fairly hard I mean hard to the touch. When you press on it you do not make a depression. Well if it's in the sun it could be an hour, if it's damp and in the shade and or the cement is crappy many hours. Ok the net coat ... Basically mix and apply as fist coat bringing the level out a tad above exsisting. Takes a board and screed off the excess... - the board should be wider than the patch. - starting at the bottom press the edge of the board against the wall. - move the board side to side - keep the side to side going and move the board up - if you tip the board back it will tend to leave more cement. - if you tip the board forward it will tend to scrape more cement off. - I would probably leaver it a smidge high. Ok let that sit. What is your present finish? Sand ? (sponge float finish) - after cement it fairly solid (before fairly hard) sling some water on it and move a sponge float across the surface in a small swirling motion. A kitchen sponge can be used or a block of wood too. Be carefull not to dig into the soft stuff! Sand with brush marks? - while cement is soft take a wide brush and dip it in water and move across surface as few times as possible and imitate the existing strokes.