Not sure if this will be helpful;
http://www.reptileforums.co.uk/forums/lizards/1056400-new-planted-tanks-diy-expanding.html

The photo's are long since gone (stoopid Photobucket) but you might get some pointers. Failing that, type in 'expanding foam' into the search bar at the top as there's plenty of past threads that might be useful. Good luck. : victory:

 

Will you be sealing it with silicone? If so then any will be safe TBH.

I use soudal expanding foam, cover it with aquarium silicone and stick my substrate of choice onto that :2thumb:

Best I've used is touch n foam which is meant for ponds errand is completely fish safe. Once cured the white stuff is OK too but the benefit of this is its black so any missed spots or cuts etc won't show. It can be pricey but a few sites sell in bulk and it works out Touch n Foam Landscape - 340g - Water Gardening Direct per tin

Thanks very much for the replies! I ended up getting the touch n foam landscape one since that is fish and plant safe; just to be on the safe side, it will be coated in silicon as well
I've been ordering stuff all week for my new terrarium/vivarium ahaha.

 

Will you be sealing it with silicone? If so then any will be safe TBH.

I use soudal expanding foam, cover it with aquarium silicone and stick my substrate of choice onto that :2thumb:

 

Best I've used is touch n foam which is meant for ponds errand is completely fish safe. Once cured the white stuff is OK too but the benefit of this is its black so any missed spots or cuts etc won't show. It can be pricey but a few sites sell in bulk and it works out Touch n Foam Landscape - 340g - Water Gardening Direct per tin

 

How's your background coming along?!

 

Just wondering how much area one 340 tin will cover? Looking to do 3d vivarium background too. How long does it take to cure?