How to fix gap under garage door?

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Set a trap at each end

Other than those trying to be funny; that's a pretty large opening. Mine goes all the way to the edge of the wood. Plus the door itself actually pushes against the stationary frame as the door reaches its fully down position because the track gets closer to the frame at the bottom. And there is a side and top gasket seal on the outside. But, even that, I still think there is a gap big enough for a small mouse to squeeze in. And actually, one apparently got in somewhere a few weeks ago. And I do have a cat. The cat brought the mouse from the basement (at the same level of the garage) upstairs into the house to play with it. Don't really know how the mouse got in. But it seems to be only that one, so far. In the OPer's case, if the bottom gasket is in good shape, I'd try adding a small piece to each end. If it's badly warn, replace the whole thing. You may have to cut off a few inches of the old gasket, on each side, and add a slightly larger piece.

Buy a short length of white door sweep. Using a hacksaw or metal cutting blade in a jig saw (for the metal portion) and a sharp knife (for the rubber sweep part) cut appropriate sized pieces from the newly purchased door sweep to match the length of the gaps. Drill 2 holes in the aluminum portion of the pieces you just cut to allow 2 screws to either pass through or screw through the aluminum. Screws should be selected (self-tapping, wood screws, metal screws, etc.) to match the composition of the bottom portion of the garage door frame (could be metal, wood, solid frame, hollow frame, etc.). Screw the pieces of door sweep into place to close the gap.

If you want it done right and to look right, buy a new door seal the full length of the door.

Mlm Mice lives matter. I let the chipmunks make home in my garage. No biggie. Detached from house.

Chipmunks are cuter than mice.

So does the track move to the side as the door reaches the floor? That would make any method of filling the space more complicated. How much does it move? Oh, you're not the OP and you're not looking for a remedy for yourself.

For sure. AIUI, they don't have bones, only cartilage, and get through spaces that look a lot smaller than they look.

Sounds right. Add more lip or replace the whole lip. The hole in the picture is big enough for a rat, let alone a mouse.

The track doesn't actually move, but it gets closer to the door frame as it gets closer to the floor. Also, as I said, there is also side and top flap on the exterior to close off wind.

On 3/3/2020 2:15 AM, micky wrote: ...

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No, as mammals they have fully-formed skeletons. Just that their anatomy is such that the head is the largest-diameter portion so despite external appearances, if it goes, so can the rest. Nice article w/ illustration at

Simon and Theodore are fine, but Alvin is a brat.

Matthias Wandel has some pretty cool Youtube videos that explore how small an opening a mouse can get through.