Post termite treatment improperly sealed holes

This appeared a few months after a termite treatment in slab construction. I thought you folks might appreciate seeing this, as the treatment may be common:

Holes were drilled every 12 inches around the perimeter for the chemical injection. The holes were filled with standard non-expansive grout. The installer said of this ‘oh, they pop out all the time’. ‘If you’re doing any sort of construction and banging around they come out’.

So I banged on a few more with my foot, and they popped out. The rest yielded to a light tap with a chisel. The typical plug appears about 10% smaller than the hole it is in, and it rattles if you wiggle it.

This is not water tight, not radon resistant, not chemical resistant and most importantly the gaps are big enough to allow the entry of termites (the termiticide used is non-repellent). See also here. Anything over 1/32" is a termite problem.

Are these holes Interior or Exterior…?
You attempted to remove the plug and succeeded?
What is your concern?

Better would be hydrostatic cement or cotton balls and epoxy. Comments?

These holes are interior, in this particular case in a kid’s room.

The concern is listed above: they are not water tight, not radon resistant, not chemical resistant and most importantly the gaps are big enough to allow the entry of termites. Once the chemicals wear out, the slab has more termite sized holes than it did before.

While any slab cracks, having unsealed holes every 12" seems a step down.

As others have posted on your blog, hydraulic cement, applied deep enough would have gone down the width of the slab and this wouldn’t have happened.
The other question is why did they drill holes on the interior of the home?

They needed a mortar bag, or other way of getting cement far enough down the hole. Many of the plugs were far thinner than the pictured example, just sort of slapped on with a putty knife. They’ve done it that way for decades.

Why were holes drilled on the interior slab? The termite company said this was standard operating procedure, to do both sides of each exterior foundation, and also any interior slab walls that show evidence of termite damage.

In your experience are interior slab termite treatments uncommon? I’ve seen several in the San Francisco Bay Area, but I don’t have a sense of the broader picture.

it looks like the termite exterminators you have hired were not professionals. Usually termite control companies inspect property before choosing a suitable termite treatment. The injection method is most commonly used where there is extensive woodwork on wall, or where the area is highly infected by termite. Injection treatment is definitely not suitable for concrete buildings as shown in pic. The more suitable treatment can be tanting for such construction type


Masood: it was a fully professional termite company, one still in business, and one with a lot more smarts than the average Orkin type saleseman. Check your spelling on the word “tenting”. Tenting was not appropriate for this building which had a heavy subterranean termite infestation. Your comment seems designed to net a link to your website, and does not reflect the discussion above.

Spammer fail!

Nobody open his link. No reward for spamming.

When I was in the termite biz we would use rubber plugs driven down a couple of inches then fill with a cement mix. never a problem that I can remember in fact every once in awhile I will perform a home inspection on a property that was treated by us for subs. plugs still in tact even after 12 years.

Could be a radical islamic terrorist?

We are in a home and there has been holes drilled recently in the concrete blocks of the interior foundation. 2 holes drilled in each block. Not plugged holes just holes? They are every 8 inches.

If this is your home then why not get some hydraulic cement and fill them .

As I understand it, the only time you drill holes inside a home is if you are in a garage with the garage being at a level (usually lower) different from the rest of the foundation, OR…if it is an external wall where there is an infestation in the wall. Yet, if the exterminator is not properly inspecting, you may find later on that the entire wall is infested.

An infested wall needs to have drywall removed, the nest removed, and any studs, bottom & top plates removed as well. If the infestation is not all that bad, you can drill holes in the wall and use foaming termiticide in cans to eradicate them.

The company I work for doesn’t use the plastic caps. Instead, when we plug holes we use a sand mixture that comes with type S mortar. Once it dries, it stays in place. I have gone to treat a home for termites to find that whomever they used before did not plug the holes they drilled. The holes are supposed to be 1’ apart to allow the rod to spray out enough chemical to do the job right. In Oklahoma, that is 4 gallons per ten linear feet. That is quite a bit of chemical just to get rid of termites.

I also offer suggestions to customers on how to prevent future termite issues such as keeping cellulose debris (twigs, branches, and leaves) away from the exterior of the house.