Grout in backgrounds

[SamanthaMarikian]

I’ve seen people using grout for hides and backgrounds in mostly arid enclosures but does anyone have experience using grout in tropical enclosures? This will be used for rock features, background, and floor to cover exposed foam etc. Or other possible similar alternatives?

 

[Coradams]

I have never considered using grout in a terrarium but to be honest, I hate grout! I hate it between the tiles in my kitchen and bathrooms! Because it is porous, it holds water and is susceptible to mold - which may be why you only see it in arid enclosures . It is also difficult to clean and keep clean. I am not positive but I believe grout will crack and flake if spread over large areas. I would use plaster of paris before I would try grout.

When I made my palludarium, I used expandable insulation foam which I then carved down to the shapes I wanted with a utility knife. I then covered it with black silicon and patted dry cocofiber and bark pieces into it. I would think you could get tan colored silicone and press sand into it to get a rock-like look but I haven't tried sand personally.

If you try silicone, here are a few things I learned the hard way:

Work in a well ventilated area
Plan on making a mess
Wear old clothes
Wear gloves
Be sure to carve down the expandable foam or the silicone will not want to stick to it.
Plan on spending the day
Any silicone that gets on the glass an be scrapped off with a box cutter

I hope this helps. Others may have more suggestions. Let us know how your project turns out!

 

[The Snark]

Because it is porous, it holds water and is susceptible to mold

Amen to that. The ideal mold habitat. I've gone so far as to hit grout with a propane torch repeatedly. A few days later when it got damp, back came the mold.

 

[SamanthaMarikian]

Amen to that. The ideal mold habitat. I've gone so far as to hit grout with a propane torch repeatedly. A few days later when it got damp, back came the mold.

Even with good ventilation? Or if i seal it with something?

 

[The Snark]

Even with good ventilation? Or if i seal it with something?

Yes. Pardon the technical here. The mycellium buries itself deep in the grout, safe from poisons or heat. They can remain dormant for extraordinary lengths of time. It only takes a few minutes or less of moisture getting to the 'body' for it to activate. It sends out whatsits that bear fruit, spores. The spores are the only visible part of the fungus. This is where good ventilation helps. It carries off the spores before they can land and start a new colony. But it bears keeping in mind, those spores are the ultimate survivalists and it only takes one to get a new generation going. So good ventilation and keeping things dry is key to prevention. BUT, those spores, and suitable habitats like grout or gypsum wallboard. They retain moisture like a sponge. See a spot of black mold half the size of a cotton swab? It's really several billion spores.

As for sealing it. Take our bathroom. Black mold central. I sealed between the tiles. For a year. Final solution was grind and scrape away the grout to give the silicone caulk a good solid purchase without so much as a tiny pin hole. Think waterproof fish tank. Even then I had leaks, just enough to activate the mycellium and the mold blasted right through the caulk.
It doesn't take moisture running down the tiles in the bathroom to supply sufficient moisture for the spores to land and get going. High humidity and dead air zones are enough, the commonest cause of 'sick' houses.

 

[RoachCoach]

Whoa whoa, whoa. Let's just take a quick chill on mold. It only can proliferate on nutritious substrate. Most of the stuff in your house is pretty tasty. Just throw some Great Stuff and carve it down. Once it is cured, it is safe enough for you to eat. DON'T EAT IT you dummy. As far as @The Snark said he is pretty much correct. You won't see the mycelium. Once you see the mold, it's already too late. That is them sending billions (with a B) of spores into the local environment no matter how sad you are. If it is black mold is up to a trained professional. If you have ever seen people cultivating mushrooms in their Tyvek suits and flow hoods, that's why. Invasive spores are the enemy and it's literally almost a sterile venture if you want something other than what is there. Spoiler alert, you can't.