Ant powder under slab insulation?

[oranjeboom]

Just levelling off my last few rooms with sand prior to laying down my EPS/PIR boards. I remember on ebuild someone suggested to me that it wouldn't hurt to sprinkle down some ant powder with the sand. It's probably overkill, but I don't want any ants in there creating a labyrinth of tunnels that may create hollows within the insulation.

 

FWIW, floor build up:

 

• Bamboo/tiles
• Meshed concrete/UFH
• EPS/PIR
• Radon barrier
• EPS
• Sand
• Hardcore

 

No issues with ants in the property and removing the old slab, there was no sign of any ants, but I've read of ants making cosy homes within EPS/EPS beads (but mostly where it's been moist).

 

So if I do use ant powder, is there anything that I should be aware of? I don't want the powder eating away at the EPS!

 

TIA

 

 

[Jeremy Harris]

The majority of ant powders use permethrin or a similar pyrethroid, and will break down within a few days in soil, so I doubt that adding this to the sand would be anything other than a short-term solution. 

 

With luck, the low temperature under the insulation will be below that at which ants can thrive.  Ants seems to do very well under paving that gets warmed by the sun, but rarely seem to appear under colder paving, at least around our old house.  We have some slabs by our old front door that is plagued with ants every year, and that sees a fair bit of sunlight.  The same slabs laid the same way by the back door never seem to attract ants, but that are is always in shade. 

Edited March 4, 2017 by JSHarris

[Gone West]

We had a problem with ants burrowing under our insulated slab. They only seem to live around the edges of the insulation and don't travel far underneath it. We used ant powder whenever we saw ant activity around the insulation and it worked a treat. They get covered in the powder and take it back to the nest and activity soon stops.

[Jeremy Harris]

Not sure if this may help, but I've just remembered that the insulation under our slab isn't laid on sand blinding over the stone sub-base, but is laid on sharp grit.  I suspect that ants may be less attracted to sharp grit than sand.  The grit looks like the stuff our permeable pavers are laid on for the drive, and that hasn't yet attracted any ants, despite being pretty warm in summer.

[oranjeboom]

Thanks @JSHarris. Mine is more of a sand than a grit. It's been in jumbo bags out the front drive for a couple of years but no sign of any ants in there. Maybe they've been waiting for a warm slab to move to.

11 hours ago, PeterStarck said:

We had a problem with ants burrowing under our insulated slab. They only seem to live around the edges of the insulation and don't travel far underneath it. We used ant powder whenever we saw ant activity around the insulation and it worked a treat. They get covered in the powder and take it back to the nest and activity soon stops.

 

That's good to hear - edge dwellers only! I did have a rat living under the cellcore EPS system in one of the extensions last year. He seems to have moved out and all holes are now concealed. Just need to make sure the squirrels don't return to the loft this year.

[Onoff]

9 hours ago, oranjeboom said:

Just need to make sure the squirrels don't return to the loft this year.

 

When i was an apprentice I worked with an old chap who had lived where I live now, years later. Back then most "houses" here were timber frame / tin roofs. Fred said that when his father and others had poured their slabs they had first put down a layer or coarse broken glass. This simply to deter the rats from chewing up through the floor.

 

We've had the occassional rat issue under the suspended floor. I think the issue is maybe where the various extension walls were put on - there's gaps below floor level. Won't be properly sorted until the floors come up like you're doing.

 

As for squirrels, had them in the eaves (dormer bungalow). I found the "cure" was to fit those circular eaves vents. Guess it just makes it too damn cold in there. Unfortunately I think they've moved to the garage!

Edited March 5, 2017 by Onoff
"former" to "dormer"