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Fake Rock Instructional for a Reptile Enclosure

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Whitney has raised and bred different species of geckos, snakes, lizards, tortoises, and other exotics since 2003.

Making Fake Rock

Making a fake rock background for your reptile's enclosure can add not only aesthetic pleasure for your, but entertainment for your reptile. By added ledges and a second story, you have expanded the amount of room that your reptile has to roam greatly.

I've created this fairly simple instructional on how to create your own fake rock background below.


(most items can be purchased at a hardware store such as Lowes or Home Depot.)

* Polystyrene foam- comes in one large sheet or a pack of smaller sheets

* Foam in a can- there are 2 kinds, make sure to get the kind that hardens. The can should say.

* Liquid nails- use this as the glue to stick the polystyrene together.

* Grout- comes in many colors

* Grout sealer- make sure it's acrylic or water based. I used aqua-mix

Step By Step Guide to Fake Rock

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Making Polystyrene Fake Rock

Other Supplies:

* Poster board- to create a 3-d model

* Box cutter- to cut the polystyrene foam into a basic shape

* Dremel tool- to cut the polystyrene foam into a more curved shape

* Sand paper- to even out the polystyrene foam when cut

* Paint brush- to apply the sealer

* Latex or dish gloves- to apply grout and work with foam in a can (can get messy and a pain to remove from your hands!)

* Sand- to add a more realistic feel

* Brown paper- to cover the floor (I would recommend something put on the floor because this project can get messy.)


1. Draw out your design on paper. (Optional)

2. Take your 'blueprint' and cut poster board to create a 3-D model to the size of the tank.

3. Trace the sides of the tank onto a sheet of polystyrene foam and cut them out.

4. Use the dremel tool to shape the sides. With each cut, make sure to check to make sure it would fit inside your tank.

5. Glue the sides together and checked to make sure it would fit inside your tank.

6. Use excess foam to creat ledges, if your plans call for them.

7. Cutting the sides of the hides. Make changes as you go along.

(If the pieces aren't perfect right now, that's fine. It can be fixed later with foam in a can and grout.)

8. Shake up the foam in a can, and proceed to use it on the ledges and steps, which serves a duel purpose, making them durable and adding visual appeal.

11. After letting the foam sit for at least an hour, you can create a more rounded look by using your finger to add just a little bit of foam. This also filled in any gaps between the polystyrene and the foam in a can.

12. Add foam in a can to the hides so that they wouldn't look quite as square.

13. Once the foam in a can had fully dried and hardened, glue the hides to the back piece. Although there were some gaps, the foam in a can can correct the imperfections.

14. Once all the foam in a can was hardened, it was time to grout. It takes about an hour for the foam to dry, but I waited much longer to make sure it was settled. Make sure that the first layer of grout you add is a watery layer, this serves as the base coat.

15. Let the grout sit for 24 hours before adding the second coat. Make the second layer of grout less watery than the first layer. I'd call it a medium consistency.

16. Wait 24 hours for the grout to fully cure before adding the third coat. Make the consistency of this layer very thick. If you choose to add sand to the fake rock, do so on this layer. I took handfuls and dropped on the wet grout.

17. Shake the excess sand off, I used a paint brush to apply the first coat of sealer.

18.The sealer dries in about thirty minutes. Add a second coat.

19. Just to make sure I added a third coat of sealer to the entire fake wall piece.

20. I let the piece sit outside for a day before bringing it into my room just to make sure all the fumes where gone.

Misc. Fake Rock

You can use this basic fake rock design however you wish. I've made humid hides, regular hides, calcium dish holders, and decrative rocks. You can come up with various projects for your reptiles. I even created a large ledge to put in my bearded dragon enclosure so that my beardies can get closer to the UV rays. It, also, ads more space to the enclosure by having more than one level.

Cleaning Fake Rock

When cleaning the fake rock, you want to use a mild soap to gently wash off the surfaces. Thoroughly rinse the entire background, or small pieces afterwards.

You may want to reseal the piece after cleaning, just to make sure that none of the grout will flake off.

Fake Rock

You can choose from a variety of different grout colors for your polystyrene rock. The color in the above pictures is gray, as it was the only color available at the time. Many times grout will come in white, rust, brown, tan, amongst a few other other colors.

If you choose to paint the grout, you may want to choose a white, or light color. Choose any color you want of the acrylic paints. You want to stick with acrylic or water based products when building something for your reptiles.

Always, let the fumes air out before placing anything into your reptile's enclosure. You don't want to harm your pet.

Fake Rock Enclosure


This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.


Ian on May 15, 2019:

What sealer do you use and what type of grout?

Thanks in advance

ryancarlsonr on June 07, 2017:


Steph on February 20, 2012:

Thank you for this post! I used your techniques to make a cave for our Sunday School class. It looks awesome! So realistic! I've had such fun creating this. My question is that I applied the first layer of grout (really watery). It has dried completely and started to crack! Will these cracks go away when I add layer 2 and 3? Or will they get worse?

thomas on January 02, 2012:

can the grout be substituded with plaster of paris i'm wanting to build one for my two bearded dragons and i'm using styrofoam packing from when i bought a crib for my daughter and liqiud nail and plaster of paris from crafts at walmart like the owner of my local pet store said to use and a few site too but i keep reading grout is better or can either be used?

Clapton on February 11, 2011:

Your instructions are perfect!!! I was able to customize everything to my specification. Much better than the hides at pet stores. Although a bit more expensive. Thank you very much for this post!

Whitney (author) from Georgia on December 12, 2010:

The items in instructional above are all safe for reptiles. I have used the above products for both bearded dragons, fat tail geckos, and leopard geckos

Sky on December 12, 2010:

Hey there I just had a quick question. I am about to make a wall for me geckos and I wanted to know if any of this stuff will hurt my gecko, Is there any after affects?

Whitney (author) from Georgia on December 07, 2010:

I wouldn't suggest it.

skyline82 on December 07, 2010:

Hi,I was wondering if it would be ok to use this as a floor with a heat mat and would the polystyrene hold heat?

Jarryd on September 16, 2009:

I'm using something I found at home depot called TileLab Matte Sealer and Finish. It's acrylic/water based and the matte finish should be perfect. I'm not far enough along to actually use it yet though.

Whitney (author) from Georgia on September 03, 2009:

Yes, that should be fine. It's what I used.

I'm not sure what polycrylic is.

Thomas on September 03, 2009:

Can the polystyrene boards be bought at Home Depot and/or Lowes as well? Also a similar method suggests using water based polycrylic. Would that be as safe?

Whitney (author) from Georgia on August 22, 2009:

Acrylic or water based is fine. I mented a brand at the top that I used and was great.

I'd reseal maybe every 6 months or so. I'm not really sure if there's an exact time frame. It just depends on how much usage the pieces will get.

bearded dragon owner on August 22, 2009:

We are at the final stages of our new habitat and are concerned about which sealer to use. We have made faux everything, three sides and the floor with caves, rocks, stairs, etc. Our biggest concern is that we use the right type of sealer for this that does NOT harm our bearded dragon, and that is going to last when he poops and pees on it. :) (we already clean that up with clorox/water solution)

Do you use an acrylic base, water base, or silicone base sealer? Great job as well. How often have you had to reseal?

zoe on July 26, 2009:

we tried to make a water fall it does not work no matter what you try to seal it all with we still got leaks but works great for all other features

fritteritter from Ohio, USA on July 03, 2009:

Very good tutorial, I wanted to do this for my hermit crabs but instead I bought several bricks of that green foam which is used for floral arrangements. It was easy and fun to combine the bricks and hollow out realistic rock caves but unfortunately it was VERY messy (green dust galore) and more expensive than your method. I have a ton of polystyrene sitting in our storage shed, so I'm definitely bookmarking this hub for my next hermit crabitat revision!

Whitney (author) from Georgia on April 20, 2009:

I wouldn't recommend it for hamster.

Hamster Crazy on April 18, 2009:

I was wondering if I could do this for my hamsters. If they chewed it, would it hurt them? If so, is there anything I can do to make it okay?

Great hub!


Whitney (author) from Georgia on April 16, 2009:

It shouldn't really crack off. Just apply the second coat and see if it helps. Make sure that the second coat is thicker than the first, which should have been soupy.

scott on April 16, 2009:

I have put the first thin layer of grout on and now that it is dry, it seems that everywhere that I touch, the grout falls off. Will it stop falling off after the third layer? Thanks.

Whitney (author) from Georgia on April 06, 2009:

foam in a can is relatively inexpensive. the overall project can get pricey depending on how large a a piece you make. I think grout is usually like $10, $10-$20 sealer, $5-$10 for styrofoam boards, $5 glue, $5 foam in a can. All HIGHLY estimated pices as it's been years since I've purchased any of these products. You'll probably get out around $50-$75+

mayyam on April 06, 2009:

wow! this is wonderful.

i really want to make something like this for my leopard gecko and i was wondering approximatly how much this would cost.

I'm a college student, so i'm on a pretty tight budget, and when i googled foam in a can all i got was really expensive (like 90$ things).

Rav on February 03, 2009:

im doing mine now ive been researching for ages and i found most peeps start the grouting really thin like Whit but apply 6 coats- not to say get really thick with the grout but each time do it a lil thicker

nice job though whit ill post mine soon

lankie on January 20, 2009:

man whitney bad a idea never thought of doing that going to have to set up a rock wall an hi die hole tomorrow for my savannha monitor thanks!!!!!!!!!!!!!

Whitney (author) from Georgia on January 17, 2009:

I don't think that it would matter, as long as you properly seal it.

cameron on January 15, 2009:

hey is this sanded or unsanded grout? does it matter really?

Whitney (author) from Georgia on January 15, 2009:

If you have the extra grout, it wouldn't hurt to do the third layer anyway. It's better that it's there, especially as he first layer should have been pretty soupy and thin.

cameron on January 14, 2009:

Hey, I am on the second coat of grout for my background and was wondering does there have to be 3 coats? i made my first coat super thick so i dont know if its neccisary for a 3rd coat.

cameron on January 12, 2009:

thanks a lot! very helpful because of you i decided to make a background for my bearded dragons cage. all 40 gallons of it bacck and both sides lol........... its taking a TON of grout but it will be worth it in the end.great work on this guide

Whitney (author) from Georgia on January 10, 2009:

I dont think that the damp sponge would work in its entirety but you could try. What you're trying to do is get rid of the excess fumes, not the sealant.

Grace on January 08, 2009:

Alright then I guess I over did it with the sealant. Sorry, last question, do you think a damp sponge would take off any excess sealant?

Whitney (author) from Georgia on January 08, 2009:

No. It's supposed to be a solid feel, pretty smooth. Not waxy.

Grace on January 07, 2009:

Is the sealant supposed to feel a bit waxy?

Whitney (author) from Georgia on January 07, 2009:

I wouldn't suggest putting it in the oven. I would try to just air it out some more.

Grace on January 06, 2009:

I've made a fake rock for my families pet leapord gecko. I found a water based grout sealer. I left the rock to vent fumes for about 48+ hours. However I found especially when I put in in her tank, the heat lamp seems to have activated more of the fumes because it smells strong of the sealer once I have the heat lamp over it. I'm debating on putting the whole thing in the oven, warm it up to the lowest heat, thurn it off, let it cool a few minutes and then put in the rock. I'm guessing it's possible that the heat is releasing what moisture is left. Not sure what else I can do...

reptihabitat on December 29, 2008:

I have been building these for years and i use them in all different types of enclosures. For snakes, my beardie, in a monitor cage, in a fresh water fishtank. BUT I use vinly patch cement or fiberglass cement. It is a hell of a lot stronger, holds up to water better and looks and feels better. Everything that I glue on is also held with nails and wires. anything that is big like a ledge I use supporting braces under it too.

Whitney (author) from Georgia on December 12, 2008:

You'll want to use liquid nails to glue the polystyrene. If you use the foam in a can, it won't be very stable.

Luke on December 12, 2008:

what did you glue the polystyrene with as ive heard superglue destroys it completely. Prick stick would work at all. could u just use the foam from the can and then slice it of at the edges?

thanks luke

Whitney (author) from Georgia on November 12, 2008:

it is possible. You would want to purchase thicker styrofoam boards and make sure that you put a good stable last layer of grout, following the instructions ab with the 1st layer waterery, 2nd less watery, and 3rd pretty thick. Otherwise, the wood would be a good idea as well. You'll just want to make sure to use wood glue and maybe even nails, but make sure to cover any sharp points and fill in any holes. The grout would be a neat additive to make the wood more realistic if you do want the rocky look. I think that the support of the foam would depend on how long the cat sat in the same spot. Definitely consider the wood, as an alternative.

I'm glad that the instructions have been able to help you.

Gen on November 12, 2008:

I'm looking for information on building a rocky crevice, but I want it for my cat. She's part bobcat, so she has this horrid obsession with den-like things. Is there any chance that this method of faux rock could support a 15-20lb weight? What I want to do is build up a base rock of about 8-10" tall by stacking up foam, and then build sides and a back of about 2" thick and 6-8" tall, and then lay a thick roof over top, maybe 6" or something. I think foam might give out if she jumps on top, and I might need a wood frame and then do the foam-shape-grout-seal trick on that. But this would be easier, so I thought I might ask if you happen to already know that it will or won't work for a heavy critter. The pics are really helpful, by the way... I've seen these directions four times now in my search, and this is the first time they all make sense!

Whitney (author) from Georgia on November 05, 2008:

The grout gives the rock a realistic feel, it holds the styrofoam, and it makes the piece more sturday.

The sealant protects the grout from falling appart and crumbing, as well as from water.

Bob for Apples on November 05, 2008:

What purpose does the grout provide? Does it help hold it together, sealent against water, or keep the gecko safe from toxins? It is not crucial but I would like to know.

Whitney (author) from Georgia on October 31, 2008:

i wouldn't recommend it, but i'm sure that it is possible. you would need to seal the fake rock frequently, i would think, but I'm not 100%.

james b on October 30, 2008:

can you make water falls out of that, and will it hold the water

Whitney (author) from Georgia on October 19, 2008:

I'm really not sure. You would need to carefully seal it with a waterproof sealer probably.

Jman on October 19, 2008:

can these fake rocks be used underwater as well? say in a acutal aqarium?

beca shine on August 11, 2008:

awesome your instuctions are so simple and i love the pictures you added. thank and my bearded dragons will love this!

Whitney (author) from Georgia on July 23, 2008:

I would stick with new grout just to be sure. You will want to make sure to cover the grout with an acryllic sealer and let it dry for at least 24 hours before putting it in the tank

Tommy on July 22, 2008:

Can it be any old grout because i have some in the garde but it can cause eye irratations

Whitney (author) from Georgia on February 27, 2008:

I'm not 100% about carpet python enclosures. I assume if you made something simple, you would be fine. Just make sure to let it fully air out before you put it in the enclosure.

Does it matter? LOL! ;) on February 26, 2008:

Hey, awesome background. Do you thnk it would be ok for me to make a much larger one to cover the back of my jungle carpet pythons enclosure? It is a very BIG enclosure so, yeah. THANX!! ;)

adam on November 09, 2007:

do you think it will be hard to make a much larger scale one for my iguanas tank its 5ft tall and 3 ft wide lol

Dylan on October 14, 2007:

Thanks that looks so AWESOME! I'm going to build one in my leos new enclosure. Thanks again

Whitney (author) from Georgia on October 02, 2007:

I guess you don't have to. I did mine in an outdoor padio. You just want to watch out for the fumes. I think outdoors would be better, so you're not catching all the fumes and because of the mess. But you could do it indoors, if you chose. Just watch the mess and the fumes.

Danielle on October 01, 2007:

Thanx a lot! I am so going to make something like that. So you have to do it outside?

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