Carpenter ants, bats besiege houses

 
Dear Jerry:  For 52 years now, we have had big ants, carpenter type, every May.  We see piles of sawdust, so we know they are causing some damage.  

I have sprayed them and the area where they work with RAID and similar products.  Repeated spraying seems to stop the visible action, but who knows what goes on up inside the structure?

I have set out jar lids of boric acid, which we have had for many years. Indoor areas. Boric acid is no longer available at drugstores.

We called an exterminator last year who discussed their treatment and left his card for us to call this year. 

I’d be grateful if you could discuss homeowner treatments of carpenter ants versus the expensive “programs” that exterminators offer.

I have read of homeowner powders that ants carry back to their nest, but do they work?   

— G.N.R., Brighton
 
If there ever was an alarm to take action, this is it.  Fifty-two years of sawdust?  Holy cow, it’s a wonder that the house is still standing.  Although boric acid is available, (Mayer Hardware carries it), it’s past the time to call for help.  

Carpenter ants will use trees, vegetation and even utility lines as a walkway to a building.  They then drop off the “walk” and look for nesting areas.  Damp wood and wood rot is a major draw, but according to exterminator John Fraysier of Castleguard Pest Management, they will also nest in solid, dry wood. 

If the nest is visible, Frazier will use a topical spray. If not, then a spray with a product that the ants can take back to the nest is used. 

Boxed in: Expect a lot of box elder bugs this year

In either case, it’s time for you to hire a professional.  No. 1, they should survey and evaluate the damage caused by 52 years of infestation, and No. 2, the current infestation should be treated.  You may well need a carpenter to remove surface trim and repair any damaged areas.  The sawdust (both past and present) should provide clues as to where the damage has and is occurring.  

Carpenter ants don’t just go away, and a professional with the equipment and experience is worth the cost.  As always, read the contract and check cost for additional treatments, since an annual inspection and treatment as necessary is recommended.  

Dear Jerry:  Your column is always informative and appreciated.  Thank you for sharing your expertise.

The question my family has is how to discourage bats from roosting behind our louvered shutters.  A few years ago we discovered bats behind two of our shutters.  While we do appreciated the benefits of having bats in the area, it is less than desirable to host a colony behind shutters on the house.  

In an effort to discourage them we took our shutters down the last two summers.  We thought that was long enough time, but when we put them back up this spring, the bats soon started returning.  The shutters are again being stored for the duration of the season.

Any advice you can offer to make our current shutters bat-proof will be very much appreciated.  Otherwise, it’s off to the store to unhappily invest in bat-proof shutters if, indeed, there are such things.

— W. & C.R. via email 
 

First, I’m glad that you do appreciate the benefit of having bats around.  They can consume thousands of insects over a season.  However, having them roost in the house or, in your case, behind shutters is a major nuisance.  

Since the shutters are removable, that’s a plus.  There are several steps that you can take and, hopefully, one or more will help.  If the bats are clinging to the back of the louvers, try stapling some plastic sheeting to the back of the shutters.  That way they cannot get a firm foothold to rest upon.  An even more permanent fix is to screw Plexiglas to the rear of the shutters.  Depending upon the siding on the house, you may need to put plastic on it as well. 

(If the shutters were fixed, I might suggest placing a foam gasket around the perimeter of the shutters.  The foam pipe insulation used around water pipes might be useful here.)   

Mothballs may also help, given their strong odor. Take some fiberglass screen or other foldable mesh, place some mothballs in it and staple to the areas behind the shutters.  The keep-off-the-furniture pet sprays may help, although I’d try the moth balls first.  High-pitched noise boxes sometimes may work. 

Before you begin the eviction process, I suggesting purchasing and installing a bat box or two nearby.  That may provide an incentive for the bats to relocate. 

Please let me know what works.       
 
Jerry Ludwig is a former contractor and home inspector.  He is an honorary member of the American Institute of Architects.  Email your house questions to jludwig@rochester.rr.com or write him at P.O. Box 25510, Rochester, NY 14625.  Please include the year your house was built and the town where you live.