Sealing/Mending settlement cracks


Old 02-17-15, 04:38 PM
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Sealing/Mending settlement cracks

I have a property located in South Florida built in 1950s.

Several settlement cracks have developed along the exterior concrete block walls. A few are horizontal cracks and one of them is vertical.

I am getting ready to have the house painted and would like to seal these cracks.

The cracks are small, less than 1/32" wide may be 1/64" wide.

I was thinking of using a tube of concrete sealer such as this:

Loctite PL 10 fl. oz. Polyurethane Concrete Crack and Masonry Sealant, but wonder if the crack is so small would I be able to squeeze the product into the crack?

Is there a product that may be less viscous that can be painted into the crack that may work better?
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Old 02-17-15, 04:53 PM
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If you do not mind a filler that sticks out like a sore thumb and does not except paint then use caulking.
Want it to except paint then grind out the cracks with a right angle grinder at least 1/2" and use mortar in a mortar bag to fill in the cracks(looks like a pastry bag)
There is not "painting" to fill a crack in mortar.
Old 02-18-15, 04:42 AM
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Both latex and polyurethane caulks are paintable although it doesn't hurt to check the label to make sure. I couldn't count the number of cracks I've caulked in masonry prepping a house for paint. Generally minor cracks are best caulked [just do it neatly, removing any excess] while larger cracks are best filled with mortar. Elastomeric paints will fill/seal minor cracks but I always like to caulk the ones I see first.
Old 02-18-15, 12:26 PM
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before you do anything, i'd want to know if the cracks're moving or not,,, an easy test is a few dabs of patching plaster on both sides bridging the crk,,, IF the plaster crks, your crks moving - just like i said on the other forum,,, but that's just us & we do this work for a living

small world, ain't it ?

mortar's ok for a static crk,,, for a dynamic crk, you need elastomeric mtls
Old 02-18-15, 03:41 PM
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There's a difference between structural movement and thermal movement. Any crack that's exposed to temperature fluctuations will "move." It will open up when cold, and then get smaller (tighter) as ambient temperatures go up. For example--the greater the temperature differential from hot-to-cold, the wider the crack opening will be. That's why for DOT work (both structural and cosmetic), we usually specified that no cracks be sealed when ambient temperatures exceeded 80 degrees F. Such is even a reasonable practice for the DIYer, as it's easier to force sealing material into a wider crack than a narrower one.

Cracks that are moving as a result of unbalanced, structural forces are in a different category. In general, it's best to eliminate the cause of why the crack is present before attempting to seal it. If that's not done, it's almost a guaranty that additional cracking will take place after the initial repair--if not at the exact same location, then just a short distance away.
Old 02-19-15, 04:39 AM
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wish bdge had been our eic when we were cracksealing conc hgwys back in the day while temps were over 100f our dot guys never seemed to grasp the issue to their credit, they did submit $ estimates on time
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