6 posts / 0 new
Last post
Cinder Block Cracks

Hi Everyone,

My new-to-me house has cinder block construction on the older portion of the house. There are some stair-stepped cracks in the block.

I can see where previous cracks have been caulked and it appears that there have been some more extensive repairs that required more than caulking. I cannot see any areas right now that need extensive repairs. All of the cracks are hair-line as shown in the photos.

1) Is caulking the best way to seal up these cracks? If not, what is?

2) If caulking is the best way, what kind of caulking should I use?

I've attempted to insert photos. Thank you!!!

Re: Cinder Block Cracks

Here are the photos


Re: Cinder Block Cracks

These cracks are not terrible, but you want to seal them before winter sets in.

Use a utility knife to remove some of the material off and to create a new V groove for the new caulking to go into. Use a good painter's exterior caulking (DAP is one brand among others), then paint over it when dry.

Re: Cinder Block Cracks

***, thank you!

We had a cold snap with about 4 inches of snow yesterday, but it is supposed to "warm up" into the low 40s by the weekend.

Is that too cold to caulk?

I am afraid we won't get much warmer than that for the winter.

Thankfully the previous owners left some paint.

Thank you again!

Re: Cinder Block Cracks

I meant w o w thank you!

Re: Cinder Block Cracks

Stair stepped cracks are a clear indicator of foundation issues. If you draw a perpendicular line from the middle of the crack, it will point directly to the spot that needs work.

You'll know if its too cold to use caulk because the caulk has teensy little instructions written on the side. When in doubt visit the web site or call tech support.

Its the wall temperature that's critical, not the air temperature that matters.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.