Horizontal basement wall crack

I have a 1/16 inch horizontal crack that runs for @ 40’ in my basement wall; it is cosmetic and not structural. For @ 28 years, it disappears in the winter and returns in the summer, due to expansion and contraction. Is there a product that is flexible enough and will adhere enough to the existing mortar and cinder block? Or, do I have to remove the existing mortar and replace with new mortar or another product? Appreciate any help.

You should be looking at the root cause (no pun intended) for the crack and the movement of the wall.
Most likely, (as you mentioned), it is clay back-fill against the wall expanding/contracting, pushing against the wall which originally created the crack, and continues to open and close the crack. Over time this problem will only worsen. No flexible sealant will ‘solve’ this issue as it’s not structural. An epoxy based adhesive will work short term, but will eventually fail, as will re-mortaring the cracked area, which is the proper fix AFTER the cause is repaired. Remember, there is likely damage to the exterior wall as well, as when the wall moves, the wall gets damaged… at a bare minimum… cracking similar to the cracking on the interior, but usually worse.

In this forum’s Structural Section, there are many posts and videos my Mark Anderson who is an expert in this area. Check it out. You should learn a lot more than someone can type in a few paragraphs.

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Thank you for your response. In the colder months the crack disappears and in the hotter months in reappears; never more than @ 1/4 inch. I had the house built in 93, and after the first couple of years of not noticing it, it does this every year since. So, I think after 29 years of the same thing, I can assume it won’t get worse.

FYI… there’s a saying out there in the Construction & Inspection Industry that uses the line about passing the “Test of Time”…
It’s BS!
Everything fails sooner or later.
Good luck with that!


There is no product that I am aware of that will resist the forces causing your horizontal crack. As Jeff, mentioned, you have to stop the wall from being pushed in first.


imo i would not put anyting in the H crack


Could you tell me why.

when a H crack opens then closes throughout year as you mentioned then if you put concrete/mortar in the crack you then likely take the ‘play’ out, the open n close away - most of those i see where someone tuckpointed a H crack and did nothing on the exterior to reduce/remove any lateral pressure the H crack widened, it opened up ‘more’ than it did before because NOW it can’t close where it used to, just saying this is what i have often seen, it’s your house so do what you like of course. Who knows, it may not widen much in coming years but it could

idiots put in an interior basement drainage system, still leaks and they tuckpointed H crack, they didn’t remove/reduce ANY exterior lateral soil pressure and tree roots acting upon the wall and lol they didn’t waterproof the actual problems which are multiple exterior cracks in block walls - very stupid but happens all the time costing many homeowners lots of green

this H crack/tuckpint shtt held together better but it really doesn’t matter because the basement still leaks, has some mold n efflorescence n homeowner is out $15,000 ish (years ago) all because another nitwit inside system chump bs’d him


If it is a load bearing wall (supporting floors and/or roof) the crack would be structural in nature. Have a qualified fouindation repair contractor and/or geo-technical (soils) engineer give you an inspection and opinion on what to do with it.

the problem with many foundation contractors is their incompetence n dishonesty

this wall got worse n worse, certainly didn’t get any better by raising the stupid grade n paint etc

have heard some say, cracks in block walls or mortar joints were ‘repaired’ by having someone tuckpoint em, sht all that is is slapping lipstick on a pig

Thought a picture might help.

Think I forgot to attach the picture. Here it is. Bob G.