Grout cracking

[Lindy325]

Hi everyone, I have been making my own hides and backgrounds. I have been using styrofoam both spray and sheet. I use unsanded grout (which I just read may be the reason for my cracking) and I put some dollar store acrylic paint in with it. I also use acrylic paint and water mix in a spray bottle to finish paint. Then use a water based aerosol sealer, like a polyurethane. I have now noticed everything cracking and falling off. I have a coulee hides in with my crested geckos so there is water use there and the majority is with my beardie so there is the heat element. What should I do to fix this?

Thanks for your help

 

[CooperDragon]

I don't have personal experience with this, but I'd check this thread for information about similar problems. https://www.beardeddragon.org/forums/viewtopic.php?f=75&t=220764