Ants under siding
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I am removing the cedar clapboard siding on my 1940 cape and a half (Western Massachusetts) and finding ants crawling around the diagonal board sheathing. Nothing horrible yet, just little nests here and there. They disappear behind the sheathing when I expose them, so I guess I don’t really know how many there are. Could be worse than appears.
Is there something I should treat the sheathing and/or stud cavities with, while I have the siding off, that won’t poison my children? They sleep on the other side of this wall. Thanks for any ideas.
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Replies
Borates are very toxic to the gut flora ants require for digesting wood, and not very toxic at all to humans . (Borates are used in everything from laundry detergent to lipstick and a whole bunch in between.)
While you have the shingles off is a good time to touch up the insulation with blown insulation. Using a cellulose with only borate fire retardent to pack out whatever is currently in the cavities reduces the boring insect risks and tightens up the air leakage.
Adding a fully adhered vapor permeable weather resistant barrier (eg BlueSkin VP100) would tighten the wall up even further, and is well worth the up-charge over housewrap.
What type of ants do you have? Try looking at Google images.
If you have large black ants they may be carpenter ants eating the wood structure of your home. Generally ants like a moist environment. You may have a leak inside your walls.
Walta
Walter,
I've found carpenter ant nests in bone-dry roof and walls. As long as they have access to water nearby they seem content to nest in warm cavities - especially ones with foam - even if they aren't damp.
Thanks Dana; I’m getting a quote for dense packing cellulose. The rental machines don’t cut it for this purpose, right?
There are a couple different kinds of ants. Some small, others larger, with wings, could be termites or winged ants.
Some sheathing planks have some rot. Those have to be replaced I suppose, yeah? The one-by pine at the lumberyard seems so insubstantial compared to these old planks — will it suffice?
Alexander,
If they are black they are almost certainly carpenter ants. The different sizes have different roles in the colony. The winged ones set out in the spring to try and establish new colonies. They land, shed the wings and then look like all the rest of the evil hoard.
You won’t find lumber like they had back in the day. Lumber quality today, unfortunately, is not what it once was. You can get “reclaimed” lumber salvaged from old buildings, but it’s expensive. If you want a good match to what you have, reclaimed boards might be the only way to go. The stuff in the lumberyard is structurally ok though.
There are large black ants that are not carpenter ants. Carpenter ants actively burrow in the wood, but don’t feed on it (as far as I know, termites are the only common pests that actually eat the wood). The “regular” black ants don’t burrow into the wood. All the ants explore everywhere scavenging for food.
There is a tar-like substance known as “tanglefoot” that is commonly used on trees, but it can make barrier strips to help block insects from certain areas. It’s not toxic, it’s just a sticky goo that insects can’t walk through. It doesn’t last forever though.
Bill
Hi Alexander -
I wrote a blog on GBA about insects and buildings: https://www.greenbuildingadvisor.com/article/integrated-pest-management-get-to-know-mike-potter-and-bill-quarles
Going after the moisture source is always the most effective way to manage the ants.
Peter
Peter,
I know that's the advice I've seen for the U. Of Kentucky - and maybe it's a regional thing - but here in the PNW, where the environment surrounding houses invariably provides moisture sources nearby, I've found that carpenter ant colonies are quite happy to nest in dry wall or roof cavities - especially those containing foam. My (unproved) theory is that foam mimics the decaying stumps they prefer in the forest. Here anyway, eliminating moisture in the building itself won't guarantee you are safe from an infestation. The ants seem content to forage for moisture just as they do for other food sources.
As most of the posters said, water or moisture is the reason they are there. If you are leaving the siding off for a short period of time to dry out, I would get a spray container and fill it with a bleach solution then spray the area. No animal, insect or bacteria likes bleach. If you notice the ants carting off their eggs then they are moving out.
QUESTION:
.Don’t carpenter ants just attack wet wood or where there have been leaks? This area is, and always has been, totally dry.
ANSWER
That’s a common misconception. It’s true that carpenter ants usually infest wood that has been water-damaged, but it’s not always the case. They’re perfectly capable of chewing into dry wood as well. The ants prefer wood that has been wet or moldy since it is softer and therefore easier to excavate galleries for their nest. They will initially move into a home where there has been a roof leak, plumbing leak, condensation, or a drainage problem. The wood may still be damp or long since dried. Once carpenter ants have established a nest in that area, they can move on to infest totally dry wood nearby."