Our termite people plugged their dozens of chemical insertion holes using a regular grout and a putty knife. 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).
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:
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!
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!
By looking at your photo of the plug, it looks like the termite technician did not install the plug fully into the hole. If properly installed, termite plugs made from rubber or plastic need to be drilled out or pounded through the slab. I have been doing termite work for 22 years using these and other types of plugs and have never seen one properly installed to fail. Failure would only occur if the hole was too big and the proper sized plug was not installed. of course, the plug would fall through the hole.
As far as termiticide coming back up through the holes it has most likely dried and has bonded with the soil. Only a sub slab leak that would force up mud and water would be a concern. This is assuming your house was not treated with chlordane which use was banned in 1988. Fumes may still rise from the chlordane.
Ask your pest control professional for Triple Seal or Super Plugs. They will most likely give some to you. They are pounded in and can set flush with the interior slab so tile can sit level. If exterior, pound them in a 1/4" to 1/2" below the surface and use concrete patch. Scuff with shoe when mostly dry and you will hardly see the patch work.
No, the actual plug is made of a flexible rubber/plastic. They are (SealTite Termite Bullet Plugs) Some of the holes they drilled probably did not go through the slab due to hitting steel re-bar. If There is dust in the holes, it should be over 3" down in there if the drill went through the slab. Therefore, the holes that didn't go through the slab are holding concrete dust still and the plugs can't go deep enough into the hole and/or were not not properly installed. Or, the Bullet plugs should have never been used on the shallow un-treated drill holes holes.
There is one other possibility. The technicians might have been too lazy to sweep up the dust and swept it back into the holes. Which, of course, is also the wrong thing to do.
