Fake limestone effect.

[PMyers]

I have previously had great success in building fake sandstone/rock walls using acrylic render and expandafoam, and wanted to look into trying a similar thing for a fake limestone effect. Again, I would be using expandafoam, but I would be looking for a much smoother coating for it to simulate the look and feel of a limestone cave. I've done a bit of a search, and come up trumps, so I thought I'd throw the question out to the DIY masses. Has anyone tried this before with any success? If so, care to share your secrets?

 

[bigjoediver]

Have you tried using hebel ( AAC ) blocks, come in 600 x 200 x 75 mm for about $4.50 from Bunnings. Can be cut and shaped with hand tools and doesn't really need coating with render when being used as a back drop just painting and sealing. It's lightweight and can be glued with tile glue or liquid nails. I laid my wall out on a 3mm sheet of mdf then glued it all together, painted it then 2 coats of pondtite then screwed it to my enclosure. Also used it to make a heat tile by drilling holes through a 300x300x40 piece I glued together and threading a heat cord through. Hope this gives you some ideas. Will try to post a pic or two when I get home

 

[PMyers]

Have you tried using hebel ( AAC ) blocks, come in 600 x 200 x 75 mm for about $4.50 from Bunnings. Can be cut and shaped with hand tools and doesn't really need coating with render when being used as a back drop just painting and sealing. It's lightweight and can be glued with tile glue or liquid nails. I laid my wall out on a 3mm sheet of mdf then glued it all together, painted it then 2 coats of pondtite then screwed it to my enclosure. Also used it to make a heat tile by drilling holes through a 300x300x40 piece I glued together and threading a heat cord through. Hope this gives you some ideas. Will try to post a pic or two when I get home

That'd be great if you could. Might go do some bunnings website surfing for these guys in the mean time. Thanks.

 

[mad_at_arms]

There is a product by megatreat called liquid limestone or similar.
Its a sealer made for outdoor pool areas so its waterproof and UV resistant. Non toxic also.
Its very thick and best applied with a spatula and damp sponge.
It may be suitable.

 

[PMyers]

There is a product by megatreat called liquid limestone or similar.
Its a sealer made for outdoor pool areas so its waterproof and UV resistant. Non toxic also.
Its very thick and best applied with a spatula and damp sponge.
It may be suitable.

Thanks. I saw that the other day, but their website doesn't really have a lot of information (or even decent pictures) to go by. I will be taking a closer look at their product (along with the hebel blocks) when I next find my way to Bunnings.

 

[bigjoediver]

Pics as promised, sorry bit crappy took them with my iPhone

 

[PMyers]

Sweet. Thanks for that.

 

[melluvssnakes]

I found that you can get a really smooth look using sifted white cement and LOTS of PVA glue. Sifting the cement is definitely worth the effort

 

[Kitah]

I was making 'fake rock' things for a stimmys enclosure, and bought a 20kg bag of white wall grout- that stuff is EXTREMELY fine and creates a very smooth surface. At least, the stuff I bought was. Mixed it with a fair bit of water like I do with the other, coarser grout I had expecting it to thicken as I used it, but it didn't really. It set properly, and was extremely smooth to the point it was rather shiny, actually... I ended up buying floor grout (significantly coarser) and mixing it in with the wall grout to make the consistency I wanted- it was far too smooth for what I wanted.

Was about $20 for the 20kg bag from a tile store..

 

[PMyers]

Smooth is good for limestone, I guess. Going to have to figure a way to get the dimpled look to it now

 

[Kitah]

mhmm not sure if its what you're after- but if you used something like grout (I'm sure it'd work with anything you used), when its half dry but still soft you could perhaps use a wire brush or similar across it for the faint 'lines' and dimples. Just an idea

 

[browny]

something like a wire brush stabbed into the face would give an effect of sorts, not sure how much though having not tried it myself, how would 'sponging' (sp?) go with it I wonder.

 

[PMyers]

I guess I can make some fake rocks with expanda-foam first and paint the grout on to see if either wire brush or a sponge would work. I'll let you all know how this goes when I give it a go.

 

[mad_at_arms]

something like a wire brush stabbed into the face would give an effect of sorts

This made my very tired brain giggle.

 

[browny]

This made my very tired brain giggle.

haha reading it now it looks bad but it made more sense when I posted (in my head anyway)
just to clarify, face was meaning the 'face' or front of the background etc lol

 

[mudgudgeon]

An ordinary dust brush with long, soft bristles will give some great effects in wet grout or plaster.
You can dab it, or brush it for different effects. Also an ordinary shopping bag wrinkled up and embedded into the surface of wet group, then gently pulled out once the group is 95% hard can give a creviced rock texture

 

[wjames]

You can use marble tile rather than limestone tiles because these tiles are moisture resistant and durable.