New Home...Bug Problems

What happens when an entomologist moves out to the country?

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Last summer, my wife and I purchased a home in the country. For the next eight months, we worked on remodeling the new house and getting the old house ready for sale. We moved in fully in April. For my wife, house hunting was a trying experience as I look at houses differently than normal folks. I remember pulling up to a few homes and telling my wife we wouldn’t be buying the house even before we fully exited the car. “Why not?” she’d ask. I would then point out various water issues and construction issues that you could see from the curb.

As a structural entomologist, I always look for pests and, of course, I’m pretty good at locating potential pest issues in any house. In one house I saw a rat in the attic; I pointed out to my wife the little doggie door downstairs. “Hey look, a rat door!” She didn’t laugh (at least not out loud).

After a long hunt, we found the house that fulfilled most all our desires with the small downside that it contained a decent number of brown recluse spiders. Brown recluse spiders in my own home? Challenge accepted!

When remodeling, one gets well acquainted with every nook and cranny of a house. I found that I had even more pressing issues than recluses. During the course of two to three PCT articles, I will relate the issues I’ve found in my home and how I’ve addressed or remediated them. In a year or so I will provide a status report on how things worked.

START WITH THE FOUNDATION. During the initial viewing of the house, I found that the 2,500+ square foot crawlspace was fairly damp — it had no plastic vapor barrier and the vents were all blocked off. The humidity was at 95 percent and many floor joists had surface molds present. The previous owners were unaware that proper crawlspace ventilation is critical to a healthy home. Also found in the crawl was a section of old wood rot related to a corner gutter leaking issue somewhere in the past, and also the accumulation of water along the foundation due to how the downspouts were situated. Old evidence of termites was also present both in the crawl and in a couple of spots inside the house. All damage was minor, however.

The first order of business after closing on the house was to remedy the moist crawl. I purchased rolls of 6 ml plastic and Temp-Vents. The house has 16 foundation vents covering all four sides of the house potentially providing excellent cross ventilation...if the old owners hadn’t blocked all the vents with metal and wood blocks.

It is not a good idea to permanently block off foundation vents.
Properly installed vapor barriers are a must for any crawlspace where any amount of moisture is an issue.
Installation of a gutter apron is necessary to help exclude pests from entering attic spaces.

The vapor was spread over the crawlspace floor and an open area was left about 12 inches from the walls to help prevent the crawl from drying out too fast. The metal sheets and wood blocks covering the vents were replaced with the Temp-Vents from inside the crawl (the outside has decorative metal vent covers). At the time this work was done, the humidity was at 98 percent in the crawl — two weeks later it had dropped by 20 percent. With good cross ventilation, the humidity will fluctuate during the year, which is good for helping to deter pest activity.

To treat the mold that had appeared on the floor joists and sills, I used Bora-Care with Mold-Care from Nisus. This product is specially designed for treatment of wood that has surface molds and other fungi. It works best when conducive conditions (e.g., lack of vapor barrier and adequate ventilation in my crawl) are corrected.

ATTIC SPACES. The house has two open attics — one quite large — and this is where most of the recluse spiders are located. Sticky traps placed for several weeks last summer collected a couple dozen spiders of various sizes. Visual inspections also uncovered signs of recluses such as caste skins from molting and the telltale wispy webs in cracks.

The attic has plenty of soffit vents and adequate ventilation that will be improved eventually with installation of a ridge vent. The presence of bird carcasses, wasp and mud dauber nests, and dead lady bugs in the attic indicated that large and numerous entry points into the attic from outside existed. As suspected, the gutters on the house were installed without the gutter apron flashing that should always be installed when gutters are secured to the fascia boards around a house.

Probably the key spot that is overlooked for pest, rodent and bird entry into a home is the gap that is present just under the shingles, at the edge of the roof by the fascia. The roof decking is never extended all the way to the fascia and a gap from 1 to several inches is present. L-shaped, metal flashing should be installed from the front of the flashing, sliding up under the shingles over the roof decking. With a gutter apron, it covers from inside the gutter and back up onto the roof decking. Not only does the gutter apron exclude pests and animals, it helps prevent rainwater from wicking around and into the soffit and is critical to the functioning of gutters. Keeping the soffits dry is key to stopping wood rot and deterring moisture-loving pests such as carpenter or acrobat ants, or silverfish from setting up shop there. Once a gutter apron (or other flashing) is installed around the roof line, you still need to close off any openings where the flashing meets at corners or edges of the roof line. I used Xcluder brand exclusion material to fill in most gaps or pieces of metal flashing and silicone sealant to make the roof line as tight as possible against pest intrusion.

DRAINAGE ISSUES. One thing I noted after heavy rains was how the rainwater exiting the downspouts accumulated along the foundation. I took the time to dig the trenches and install drainage pipes hooked up to each downspout and directed into my pond. Directing the water coming off the roof away from the foundation was another link in keeping the crawlspace as dry as possible.

TERMITE PROTECTION. Every structure here in the southeast U.S. (I live in West Tennessee) should be protected from termites. Since my new home already has evidence of a previous infestation that has been treated, I decided I wanted to continue that protection. I installed BASF’s Trelona ATBS Annual Termite Bait system around the house and I’m checking the stations for activity on a prescribed basis. To date, I have yet to have activity in any station but they’ve only been in the ground a few months.

SUMMARY. Many of the previously described efforts are atypical of services provided by many pest companies, though most in the termite business install vapor barriers and foundation vents. All of the steps mentioned, however, are important to long-term pest control as they focus on correcting conducive conditions and limiting pests’ access to moisture or access.

The author is with Stoy Pest Consulting.

July 2018
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