DIY Rock Walls Longevity

Monkeytank · Nov 30, 2015

I made a rock wall with Quickrete Hydraulic cement and Great Stuff Pond Foam about a year ago. Now the cement portions are expanding and cracking the egg crate that was the structure it was built on. Where it cracks, it crumbles and falls down, taking some pieces of egg crate with it. The foam sections were covered with UV resistant epoxy and sand, and they seem to be okay. I know others are having this same problem with cement. For those of you who have used the pond foam, how is it lasting for you? The Great Stuff page says it "lasts years". I'm going to build another rock wall, but this time I don't want to use materials that are going to fail on me in a few years. I'm looking for feedback from people who have done this and have had the walls in their tanks for long enough to assess their longevity. By the way, the cement was mixed thoroughly and given several days to cure, so don't thread crap about that.

Dtackett · Nov 30, 2015

got a buddy who has a DIY rockwall using the great foam. instead of concrete he used rock rubble and epoxy. hes had it up for 5 years and as of last month when I saw it, it looks amazing still.

ReeferBob · Nov 30, 2015

I built a wall from just the black expanding foam and egg-crate. Sprayed it on, while still wet inserted rocks and sprinkled sand all over. Been up for like 3 years no issues.

I am taking it down anyway due to not being able to clean the tank very well with it in, but that is something else.