Vinyl siding corner posts
The outside corner post on vinyl siding is hollow. Mice can't climb the vinyl, but inside the post it's just wood and rigid insulation, and they climb that straight up to the soffit and into the attic.
At your house
Not checked yet
Look at this spot with the free check. Your answers stay on this device.
Where to look
- Every outside corner of the house where two vinyl walls meet at a corner post.
- The bottom of each post, just above the foundation. Kneel down and shine a flashlight up into it.
- An open, hollow channel at the bottom means there's a path up inside the post.
Sign to look for Dark, greasy rub marks or droppings at the bottom of a corner post.
All of this is checked from the ground. No ladder needed.
Why mice use it, and the common mistake
Why mice use it
The post is a hollow channel. Mice can't climb the smooth outside of vinyl, but inside the post it's wood and rigid insulation, an easy climb straight up to the soffit and the attic.
Common DIY mistake
Filling the post with spray foam. Foam swells the vinyl, doesn't stick to it, and mice chew right through it.
The lasting fix
Pressure-fit 1/4-inch hardware cloth into the bottom of the post, then seal around the edges with sealant.
The lasting fix, step by step
Shine a light up into the post
Kneel at each outside corner and shine a flashlight up into the bottom of the post.
Cut the hardware cloth
Cut a piece of 1/4" hardware cloth a little bigger than the opening.
Press it in tight
Fold it and press it up into the bottom of the post so it fits tight with no gaps at the edges.
Seal the edges
Seal around the edges with sealant so it stays put.
Do every outside corner on the house. One open post is enough to let mice into the attic.
Materials
- 1/4-inch hardware cloth, 19- or 23-gauge, stainless or heavy galvanized
- Exterior-grade sealants or adhesives (not standard acrylic caulk)
- Tin snips, caulking gun, gloves, flashlight
Safety notes
- Wear gloves. Cut hardware cloth edges are sharp.
- Leave the weep slots along the bottom of vinyl panels open. They let water out.
Before you seal the last gap
- Make sure nothing is still living inside. If mice are already in, set enclosed snap traps along the walls as you seal, never as a substitute for sealing.
Related spots
Mice that use this gap often use these too. Check them on the same walk.
When in doubt, seal em out.