Repairing holes in concrete to be used again.

May 12, 2015 3:24 PM

I drilled two uneven holes in a cement wall. Is there a compound that can fill the hole and withstand re-drilling?

Or should I use hydraulic cement or anchoring epoxy and set my lag shield anchors while curing? If the latter, which option is best?

posted by mizrachi to Home & Garden (8 answers total)

I'm not aware of any material that can be used as you describe, but have you considered drilling larger, even holes that obliterate the original uneven ones and then using larger anchors?
posted by contraption at 3:47 PM on May 12, 2015

Response by poster: I have not as that would require that I enlarge the holes to the racks I am hoping to fasten to the wall to accommodate a larger lag bolt.
posted by mizrachi at 3:54 PM on May 12, 2015

I suggest enlarging one of the holes to level them out and then filling with epoxy putty along with the anchor. I've had good results with epoxy putty being very durable. I would not use cement as little bits of it tend not to set up hard enough and it may expand while setting which causes stress.
posted by GuyZero at 4:00 PM on May 12, 2015 [1 favorite]

I think I've used Loctite brand all-purpose epoxy putty FYI.
posted by GuyZero at 4:02 PM on May 12, 2015

What do you mean by cement wall? Hollow masonry blocks? Reinforced concrete? Something else? Cement wall is not a term that makes sense when we are talking about a specific construction.

If it is reinforced concrete that you mean, have a look at the various chemical anchor products available. Start with Hilti HVU and similar or Ramset Chemset (which may not be available or under a different name wherever you are).
posted by deadwax at 4:33 PM on May 12, 2015

Response by poster: I believe it's hollow masonry blocks.
posted by mizrachi at 4:38 PM on May 12, 2015

You could drill the holes oversize and then glue in threaded rod with a gap filling anchor epoxy. RedHead C6 and G5 are both rated for oversize holes.
posted by doctord at 4:49 PM on May 12, 2015

In that case I'd agree with contraption above, filling a hole in a hollow wall with epoxy is unlikely to go well.

Are you placing the lag bolts in a mortar join? This sheet from Powers indicates this is the only point a lag bolt should be used in a hollow block wall and I'd be inclined to agree. An expanding mechanical anchor expanding against the air in the middle of a block isn't going to do much and I've seen a lot of problems with this over the years.
posted by deadwax at 4:51 PM on May 12, 2015