Replies

1. 
   MalibuJim | May 07, 2002 01:38am | #1

   I've never stained a block wall, but I just have an observation that you should be aware of. Most CMU walls have the cells filled only where there is vertical reinforcing steel (around here min. every third cell or 24") other walls are solid grouted.

   I've noticed that walls that aren't solid grouted stay wet longer at the grouted cells when sprayed with water. This is intuitive and perhaps acrylic top coats would dry unevenly?

1. 
   outside | May 07, 2002 02:00am | #2

   MALIBUJIM,

   Thanks for the warning, I'll let you know if that happens. For this case it won't matter due to limited visibility of this wall and the fact that it is a retaining wall and all the cells are fully grouted. This could be an issue for an older wall on my property that I was considering staining if the this wall works out well.

1. 
   BillHartmann | May 07, 2002 02:55am | #3

   They make concrete acid stains that usually give a molted effect.

   Do a search on "concrete acid stains". You will find a lot of information. As they are a chemical reaction I suspect that they will work outdoors. But I don't have any idea of how they would work on blocks.

   Also there are oil and latex concrete stains. Check with a Sherwin Williams, Benjam More or similar full line paint store.

   You could get a could of different colors and then spong paint them.

2. 
   IronHelix | May 07, 2002 05:21am | #4

   Into a 5 gal bucket pour about a gallon of water, add portland cement and agitate using a drywall mud mixer. Continue to add portland until you reach either a thick brushable consistency or add portland until the mix would be towelable.  Wet the block surface. Apply  a coat in 1/8" to 1/4" thickness. Apply a second coat if needed

   You may add sand(fine-coarse) for texture,  and/or mortar/concrete colorant.

   You can buy a product called Quikwall that will allow you to parge/plaster the surface to cover the generic block look.  Quikwall comes in white or gray,,,,you can add colorant to it also.............................but

   It is more expensive per bag (3x)to purchase than portland.   The portland mix goes a long way in the  brushable (pancake batter) consistency.

   Give it a try.................in a wet shaded area the parge will allow for a nice moss growth.

   .............................Iron  Helix

1. 
   outside | May 08, 2002 09:18pm | #5

   This idea sounds like a thin stucco like treatment. I like the sounds of it and will test it out on a different wall on my property. I will still probably try to stain the retaining wall as an experiment since it really will end up being barely visible.

   Thanks to everyone who replied!

   Scott

1. 
   Rein_ | May 09, 2002 07:04am | #7

   If you follow Iron's plan, make sure you keep the wall moist for a few days after coating. It will make the parge much stronger. Mist it and try not to let it dry out.

3. 
   MarkH128 | May 09, 2002 04:44am | #6

   I saw this on Bill Nye the science guy show. Blend milk and moss together. Pour on surface. Moisten occasionally with water. Moss will begin growing where applied. This might work assuming you like moss, and the area is friendly to moss growth. You could collect many varieties of moss for color and texture variations.

1. 
   outside | May 09, 2002 05:58pm | #8

   Bill Nye is cool. We live in San Diego and the retaining wall in question faces south. Probably not a good location for moss. I hope to someday do a large addition to our house. After the addition we will have a north-east facing microclimate area that the moss thing might work in. I know that we do have mosses native to this area, I have seen them in some of the local canyons. When you say "Blend milk and moss together" do you mean in a blender? Sounds like a moss smoothie. Bleh

   Thanks again everyone.

1. 
   MarkH128 | May 09, 2002 06:45pm | #9

   Yes, blend in a blender. The milk feeds and glues the spores to whatever they are brushed onto.