Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

Our termite people plugged their dozens of chemical insertion holes using a regular grout. Needless to say the plugs are popping out left and right. (They tell me that is normal, the plugs pop out in all their jobs).

Failed termite hole seal in slab construction

How would you suggest sealing these holes, restoring the slab to the original condition, and keeping termiticides from leaking up?

I realize the termite people never cleaned the holes of concrete dust, so I'm prepared at least to do that: cleaning hole

share|improve this question
They tell you that it's normal that plugs pop out and harmful chemicals are exposed in your house, potentially to children? Well first I'd be reporting them to the EPA and FDA if they didn't pay to have someone who knew how to work with concrete over to fix your house TOMORROW. –  The Evil Greebo Sep 5 '12 at 8:57
That's such an awesome statement of the building industry status quo. "Yea, we're supposed to suck. Pay me." Unfortunately, since you did pay them already, you will probably get ignored unless you affect their future business, like the EG says in the above comment. –  dbracey Sep 5 '12 at 15:32
Try OSHA and Cal-OSHA (EPA probably won't do anything, and FDA has no involvement here). –  dbracey Sep 5 '12 at 15:40

2 Answers 2

up vote 7 down vote accepted

If you do it your self (not endorsing, and see comment by The Evil Greebo) you could put a more secure plug in by using hydraulic cement.

To ensure that it does not come out, holes or cracks are usually back cut (the hole is made wider below the opening so that its diameter is greater than the diameter of the opening). This can be done with a small masonry chisel and a small sledge hammer. Start chiseling about 1/2 to 1 inch below the opening and go down about 3/4 to 1 inch deep. You just need to get it a bit wider (1/4 inch greater all around) than the hole.

The hydraulic cement is used like a putty and it expands slightly as it dries to lock it in. Follow the instructions, especially about moistening.

If you are doing this yourself, use a good mask and gloves because there have been harsh chemicals in that hole. Let the chips and dust fall in the hole. Do not vacuum them out!

share|improve this answer
Also remember to apply concrete bonding agent to the hole before you apply the hydraulic cement. Even though Hydraulic concrete expands to lock in, adding the bonding agent is never a bad thing. –  The Evil Greebo Sep 5 '12 at 16:26
Excellent point. –  bib Sep 5 '12 at 16:57
I found this quote from the Cement Manufacturer's Association "Being a hydraulic cement in itself has nothing to do with expansion, although some hydraulic cements will shrink less than others, this is due to them being a sulfoaluminate based cement, not a Portland cement and has nothing to do with them being a hydraulic cement. " –  Bryce Sep 7 '12 at 1:52
Cleaning the hole appears crucial also. Apparently even the expanding cement won't do well if the hole is dusty. Note in this case there are dozens and dozens of such holes. –  Bryce Sep 7 '12 at 1:56
@Bryce The problem is that poison has been poured down these holes. You do not want to suck out dust that may be contaminated with it. A bit of water sprayed down and bonding agent as recommended by The Evil Greebo should resolve the dust issue. –  bib Sep 7 '12 at 2:04

The concrete shouldn't pop out... I'm guessing the mortar they used was no good. Just buy brickies mortar from the hardware or sand and cement Mortar is stronger as there is more cement to sand. mix with water and a squirt of bonding agent will make it even stronger (we use bondcrete). Mix until it's a moist workable putty. before filling the hole, break off a small piece of styrofoam, underlay, or even toilet paper and stuffit 1 cm below the surface. this is to hold the mortar in place. roll the mortar in your hand and break it off into the hole. use your thumb to press it down and into the edges.

We use this everyday and have retreated many jobs 8-10 years later... the holes don't fall through. Avoid water blasting directly onto the holes of course but those holes should be as strong as they need to be. easy, cheap and quick!

share|improve this answer
The holes were full of powder from the drill. –  Bryce Feb 19 '14 at 1:51

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.