How to Repair a Crumbling Foundation Part 3 of 3
Tim demonstrates in this video, the magical cement paint and how to mix up strong and sticky stucco repair mix. It's all magic.
This is the last video in the series.
[Lynn asks] "How do you get the new stucco to stick to the crumbling stuff?"
Okay that's a great question. So Lynn wants to know how are we going to get the new stucco to stick to the old stuff, so it doesn't fall off in a day, month or a year or two.
Here's an old trick that was old to me many, many years ago by some masons. This is a truly a secret trick. I've written about it a lot. It's one of those pieces of information that goes from history to legend and legend to myth in the construction field. That happens all too often. I am trying to make sure it doesn't happen here.
So this is a little bucket of quick setting cement, but I got at the hardware store. I would have preferred to get regular old Portland cement, because Portland cement doesn't set up as fast and you have more time to work with it.
You can see that this is just regular powered cement and they have added some other ingredients so it set up faster. Take a little cement and add some water to it. Mix it up to make cement paint. Mix it to the consistency of latex paint.
Now that the concrete blocks are clean and all the loose stuff is off the foundation blocks, take a little spray bottle, or a sponge, and lightly spray the block with water. Not too wet, just damp. Then take your paint brush and paint on the cement mixture. This is the glue that will hold the stucco to the foundation.
I like to mix up the stucco first, since it will last a good 45 minutes to an hour. That is as long as you are using the regular Portland cement, and not the fast setting stuff.
Once the stucco is mixed up, it only takes a few minutes to mix up the paint. Paint this on to the area to be repaired just like you would apply regular paint. Not too thick. This does two things. First, the moisture in the water in the cement paint soaks into the concrete block so the water that is in the stucco mixture doesn't get sucked into the block too quickly. That is really important. It is gets pulled in too quickly, it causes it to weaken and makes it harder to work.
The most important thing is you only want to paint on an area that you can cover with the stucco mix right away. Therefore, don't paint a large area of the foundation as the paint will dry quickly. In a breeze, it can dry in a few minutes. You don't want it to dry before you have a chance to cover with the stucco patch. You don't want to use the fast setting cement because it will get hard too quick. Just use regular Portland cement.
Prior to you mixing the cement paint, you will have already mixed up the stucco. All the stucco is sand - regular medium sized sand. Mix two parts sand to one part Portland cement. Blend it together. Notice that the sand was dry. Dry mixture the two parts together. Then add some water and continue mixing. Don't add too much water. You don't want it too thin or it will run off the foundation. You want a consistency that won't run off the trowel.
Apply it to the concrete block after the block has been painted. The more cement you add to the stucco, the sticker it will be. It needs to be sticky enough to stay on the wall. After applying, you can use the putty knife to shape the stucco to match your existing profile. As it gets harder, you can take the sponge and lightly rub it to give it a little more sandy texture. Or use the putty knife to make a smoother finish.
It is really simple. Working on an overcast and slightly cool day would be best. The slower the stucco dries, the stronger it will be. You can do the same thing at your home too.
Here are links to all of the videos in this series: