Camel crickets are getting inside house and the entry point appears to be a gap between foundations.
Occasionally, we see camel (spider) crickets in the bathroom of our addition. An exterminator identified a potential entry point as a ground level hole where the foundation of the house and the foundation of the addition meet. This appears promising because this is only 3 feet from the bathroom where we normally see the crickets.
We have found camel crickets in other places of the house but finding and patching small holes in crawl space vents appears to be limiting their access. Now we are seeing them in only the addition.
The addition was added about 25 years ago and the house is 50 years old. The house foundation goes at least a few feet down. We do not have a basement but the floor of the lowest level is a little below ground level. The addition's foundation is higher than the main house. We live on a hill with the ground rising behind the house.
The hole is at ground level where the original foundation and the addition's foundation meet. It is about 3" wide and 3" tall and very deep (maybe length of the addition). If I send a endoscope in the hole, I can see the flat vertical face of the original foundation (on the left), dirt and large rocks below, and a rough concert surface that looks like the bottom of the additions foundation above. To the right, the top and bottom of the hole taper off together.
Possible Solution: Patch the Hole
I would like to patch/fill/seal this hole. But it is at ground level where the foundations meet, the surfaces are all very rough, and I am not what is safe for the foundation.
I have scheduled some contractors to come out and look at this but I know nothing about foundations so they could tell me just about anything and are likely not to explain things nearly as well as SE.
Is it typical for there to be a gap underneath the edge where one foundation meets another? Is it a problem?
How can I fill/seal this void to keep critters out? Is it safe for the foundation?
Suggestions for troubleshooting this would be welcomed too.
Spoke with contractor who does foundation repair and he will be looking at it on 8/29/2016. Over the phone, he said that the open space under the addition's foundation could have been caused by the settling of dirt. He also proposed packing additional dirt in to make up for the settling.