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Carving styrofoam to look like stone, brick, or cinder block is super easy. Perfect for Halloween decorations or haunted houses. I would even go so far as to say my technique is almost fool-proof.

Foam selection is probably one of the only ways you could go wrong. It needs to be EPS (expanded polystyrene) foam. Most commonly found in white. The pink or blue extruded polystyrene will not work. So make sure you have the right stuff to start. In my example, I will be making a faux cinder block effect. I may show some other textures and patterns in the future on my website. If you want a bit more detail on the whole process, check out my build article as well.

Step 1: Laying Out the Grout Lines

Traditional cinder blocks measure 8" tall and 16" wide. Make horizontal lines with a permanent marker 8" apart and vertical lines 16" apart. Stagger each row for the "brick style" pattern.

Step 2: Cutting the Grout Lines

There are several ways to do this. My favorite is the hot knife tool. I also showed a couple other ways to do it with a knife (K), router (R), and hot knife (HK). Each has their own sort of look now but they lose that uniqueness in later steps.

Step 3: Give It Some Texture

Using whatever method you prefer, cut some voids into the foam. Make it as varied as possible and try to move around all over the panel at random. Doing it like you would read a book from left to right and top to bottom can give it too much of a uniform or segmented look. So remember to work in random spots. Also try to mimic chipped out corners and blemishes. A wire brush does pretty well with this.

TIP TIME - don't worry about perfection at this point - the next step is what makes it come together

Step 4: Hot Stuff!

Using a heat gun melt the surface of the foam. Heat guns with auto-cool-down last a lot longer than the ones that don't. I have a complete list of the tools and materials used in the web article if this is a project you want to give a try.

I start with the grout lines. Melting them to the point of where they start looking like mortar. Remember you can always come back and heat it up more if it didn't add enough texture. So go easy until you get the hang of it.

After the grout lines are done move to the field of the blocks. I can't stress this enough, all you do is melt the foam! It looks like there is a ton of time and experience needed for the final result but there really isn't. And it is one of those oddly satisfying things to do. Seriously give it a try.

I should note - cutting foam with hot wire tools gives off smoke and gas that is less than healthy for you. Heating the foam with a heat gun gives off far less smell but do it outdoors and/or use proper breathing protection.

Step 5: Paint Your Way to a New You (or at Least Wall)

WATER BASED PAINT! Yes, you need to use water based paint. If it is not water based, chances are it will chemically melt the foam. Spraying the paint helps preserve the texture we got with the heat gun but rolling or brushing is possible. If you can, spray it.

A base coat of an earthy color always seems to work well for the cinder block look. If you really want to sell the effect, airbrush a slightly darker color into the grout lines and depressions and it really pops. Or in the case of the panel meeting the ground, a bit of green adds the look of mold or moss build up. Just get creative with it. You can add vines or ivy like I did in the tower I made for the musical Shrek.

Again, if this is something you want to try out, check out my website article for more information and a list of tools and material used in the project.

Thanks for checking it out!

-Ferry

<p>i am really going to try this very soon to give a face lift to one of my side walls in my room . i love the look and it is worth its look </p><p>yamuna</p>
awesome - let me know how it goes!
<p>Dang, wish my fiance wasn't allergic to this stuff. This looks amazing</p>
<p>Awesome. Great work. Have to try this. Keep up the good work. Thx.</p>
thank you, I appreciate it!
<p>Wow, U da'man! great projet, great video.</p>
thanks much!
Great instructable. Better than the way we used to do it in theatre by sheets tacked to frames then painted to look like walls. More realistic.
<p>thanks - whatever gets the job done</p>
Awesome. Good job and perfect video
<p>much appreciated!</p>
<p>Absolutely awesome man! </p>
<p>thank you kindly!</p>
<p>Not only creative but one of the best video I've seen.</p>
<p>I appreciate that!</p>
<p>Good to see another theatre technician on here.</p>
<p>I'm no pro theater guy but love to do it when I can find the time - I made a theater workstation - https://nickferry.com/2014/10/custom-mobile-work-station/ - if you haven't seen it yet you may want to check it out</p>
nice cart, what to you use to transport it to and from the work site? you may not be a professional theatre tech, but you drink coffee like one.
<p>lol, coffee and I are good friends - trailer or van and with ramps I load it by myself - if loading into a full size pickup truck I get someone else to help just so I don't roll it off the ramps</p>
<p>your wall would be great for a small garden on a patio like mine! excellent job!</p>
<p>very cool - thanks!</p>
Yeah so this gave me a really great idea on how to decorate my foam board in our camper!!!! We had to put it up in the windows due to extream heat!! Its just ugly on the inside, but now I just might be able to fix that. Thanks for showing this idea.
<p>very cool - glad you got some ideas!</p>
<p>Thanks for the tutorial, you make it look easy. I can't wait to jump into this and make some panels for my sons nerf wars and the local LARP group. I wonder how it would hold up to a paintball war. :) This is extremely nice work, and a great tutorial.</p>
<p>it wouldn't hold up well for paintballing but LARPing or nerf would be fine</p>
<p>My tool shed will never be the same. Hopefully I can water proof it for exterior use.</p><p>zapp</p>
<p>there are a few things you can try to water proof it - spray cement or rubberized coating for starters</p>
<p>This is an absolutely beautiful build. Well done Sir! :) The school and audience must have been very impressed. A loan to other venues could be beneficial.</p>
<p>everyone seemed to like it - which is all I can ask for</p>
<p>hello, cool really cool stuff.</p>
<p>thank you!</p>
<p>How can you harden the foam after to be able to take mild bumps? For example to make a part of a wall</p>
<p>rubberized coating or spray a cement skin - as is, it dings fairly easily </p>
<p>You have to right click to open. also the fireplace embers are made from cardboard and cellophane with white light because my orange Halloween ones died on me last minute! so much fun to do!</p>
<p>https://www.facebook.com/photo.php?fbid=10154422774987468&amp;set=p.10154422774987468&amp;type=3</p><p>this is my little fire place I made for the front of my desk at work, I was hasty making my bricks but it doesn't look half bad. I also go this idea from either this page or pinterest . </p>
<p>Cool! Does a wall like this have soundproofing qualities?</p>
<p>Almost none. Actually blocking sound requires mass. <br><br>https://acousticalsolutions.com/how-to-soundproof-acoustic-foam-does-not-block-sound/</p>
<p>How can you harden the foam after to be able to take mild bumps? For example to make a part of a wall</p>
Wow, this looks so realistic! Nice work!
much appreciated!
<p>Very nice with realistic effect. </p>
thank you!
<p>Nice! It looks totally real!</p>
<p>thanks - that is my favorite part!</p>
<p>Top work mate, looks great,</p>
<p>thank you!</p>

About This Instructable

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Bio: I like to build and make things with my hands. Think it, Build it, and repeat.
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