I've had this gap under this door as long as I've had the house. The only reason it bothers me is because chipmunks like to come into my garage and . So how do I fix this? Even where the rubber isn't collapsed it doesn't seem to rest on the ground.

 

It looks like it just needs an adjustment on the garage door motor.

IIRC, there was an adjustment screw on the motor body that I worked with when helping install a newer chain-drive Craftsman. Closing larger gaps required adjustment of the chain by disconnecting and reconnecting it to the drive.

 

I think the concrete there may have settled over the years. On the right side of the door it is a bit off the ground but the gap is much wider on this side. I'll see if there is some adjustment that can be made to get the door to go down a little more.

Is that black piece on the bottom of the door (rubber?) replaceable? I think it's shrunk or dry rotted.

 

I thought that the side looked a little lower then the concrete towards the center of the door, but couldn't tell for certain.

Yes, the weather seals are replaceable and available from various chain and hardware stores. The only issue is how the original seal is attached to the door- some will take more work than others to replace.

G/L.

 

Try something like this

http://www.autogeek.net/garage-door-seal.html

 

you can adjust your garage door springs so that one side has slightly more pressure than the other and it will cause the door to be slightly crooked dropping that side, adjust the garage door pressure and down travel so that its slightly more and get a new seal for the bottom of the door. I did that to my neighbors and it seals tight all the way across.

 

and if the above isn't enough you can also put a double seal on that side or the door... my dad's garage door leaves a gap on the left side due to the concrete settling... unfortunately when i tried to adjust the door down more on that side, the right side would gap...

 

+1