Storystore Backer Rod 1/4" Diameter x 16.4' Length Black EPDM Rubber Caulk Saver, Foam Backer Rod for Gaps and Joints Concrete Expansion Joint Filler

This stuff is the perfect balance of strong/sturdy but stretchy and flexible. I used this to fill a gap between the wall and my new live edge bar top and honestly it could nearly replace the need to caulk it at all because of his it fillso ut the gaps. Get one size bigger than you think you need because you can pull it and work it into the gaps.

The backer Rod will reduce the amount of caulk you use when caulking the seams of the pool coping next to the sidewalk, I push the backer rod in place and then stretch the backer rod so it gets thinner, than I release it to fill the gap, buy the size that's a little bigger than the space you are trying to fill.

Solid and a good way to fill cracks

Most of the backer rods listed are pretty open foam and light duty. This backer is dense, you notice it as soon as you pick it up the weight is substantially more. In use it is very rubbery but flexible, just not as much as the lighter foams, so be sure to measure carefully as gaps that are smaller it wont go in. It packs in well and appears to be very sturdy. My application is gap between asphalt and garage entrance that has opened up over time.

Have used the gray foam backer rods for years & years & years! My apts always have very drafty gaps in the sliders, always!The 1/4" is perfect to fill the gap (hard size to find) & help keep the a/c from being wasted, too expensive!Only negative for me is the smell, horrendous!! But it does the job perfectly!!Will give it a month... will see.

I was pleasantly surprised when I opened the package. I was expecting that dark gray, air-filled foam like you get at the big box DIY stores. This is heavy duty, truly black, dense rubber foam. Well made rod. Impressive. It's worth every penny.

Works great as barrier for screen room walls keeps bugs and water out

I used this to run along my cement patio, where the house/foundation come together, as weeds would grow all the time! Problem solved! Also, I think it helps deter water/rain from entering!!