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Fun with Foam Core - Create a Basic Room Shell - by Audrey (Diva Details)

Fun and foam core. Those are three words many diorama addicts would never put in the same sentence. Unless it was preceded with the word: not.


Before I begin, thank you to DeeinNJ, your official Diorama Diva instructor, for allowing me once again to host another Tuesday Diorama Discussion.


Just to recap, the last Diorama Discussion we had -- an open forum in which everyone on the board was invited and encouraged to post their diorama pics under one thread -- was a resounding success. The board was absolutely inundated with outstanding diorama photos and ideas that ranged from simple to outrageously elaborate. Though each setting was as different as the next, for the most part, what each room had in common was the room itself.


On that note, though this has been written about before, I thought this would be a good time to get back to basics and show you how to create a simple room shell. Although there are many ways to create a room shell as well as many types of materials to do it with, today we're going to focus on foam core. Why? because it's lightweight, fairly sturdy, inexpensive and easy to cut.


Stop laughing and rolling your eyes. It IS easy to cut, I swear. You just need the right tools. So, without further adieu:


For those who aren't familiar with it, you can pick it up at any craft store or craft department, and at most office supply stores like Staples, Office Depot, Office Max, etc.


For this project, I took a 30" x 40" foam core sheet and drew a line across the center at the 15" mark, then scored it with an X-Acto knife. After that, I very carefully folded the foam core in half so that the rough cut edges were on the outside, and the smooth, uncut side was on the inside. (Tip: Try this technique on small scrap pieces first before moving on to your main sheet.)


Don’t worry if the edges are bumpy and rough, because the next step is to leave the foam core folded in half and put a piece of wide, heavy tape over the lumpy, exposed edge. Not only does it give the fold line strength, but it hides the lumpy bumpy mess. For the sake of aesthetics, opaque (as opposed to see through) tape is best.


When you're done (though it's hard to see), you should have something that looks like this:



What you've just created is a 15" high x 20" wide x 15" deep floor and back wall combo.


Next, set that aside and cut another piece of foam core that's 15" x 15" for the side wall. Ooooo, I can hear it now: "Oh no! Not more foam core cutting!" No worries. Here's where it gets easy. To make beautiful, clean cuts, buy yourself a foam board cutter. It doesn’t look like much but it makes SUCH a difference. Oh, and while you're at the store, be sure to pick up some 'T' pins, too:



After you've cut your side wall(s) out, if you plan on adding set in windows, this is the time to do it. (Tip: make a guide line with a ruler that's parallel with the ceiling area to make sure that the window opening is straight.)


If you don't want to make them yourself, there's a wide variety of pre-made windows that can be purchased in a miniatures store, miniatures departments, or online. Even though they're small, don't overlook 1:12 scale windows. Some of them are actually quite large, and even the smaller ones if used in a small space or doubled up side by side can work when used with the right window treatments and furnishings. Here are a couple of photos to give you an idea of what's out there:



The photo above shows a playscale or 1:6 scale window (designed for 11 1/2" sized dolls) next to a 1:12 scale window (designed for small dollhouses). 


The window on the left is under the brand name Jamestown. I bought it here: though there are likely other places that carry them, too. The window on the right is by Houseworks. I found my Houseworks window in the miniatures department of AC Moore, but you can also find them online.   


Check the packaging that the window comes in. It should include an installation template. In this case, it’s on the back of the box: 



If your window didn't come with a template, then you'll either have to create your own on a piece of paper, cardstock, etc., or trace the shape directly on to the foam core wall. 


For this project, I used a 15-pane Houseworks 1:12 scale window. Here's the bare wall with the window opening cut:



Yikes, those edges are rough. That wall was part of my very first foam core diorama, and instead of using a foam board cutter, I used a regular X-Acto knife. What a nightmare. That project alone nearly put me off foam core dioramas all together.


Skipping ahead a little, now it's time to decorate your walls. There are endless ways to do it. You can either buy colored foam core and leave it as is or buy white and paint it yourself. Add visual interest with "wallpaper" on half the wall and leave the other half un-papered. Divide the two sections with 1:12 scale chair rail molding. Or, paper the whole thing. Add borders, wood or metal embellishments, you name it. 


During that project, I decided that removable wall coverings were the way to go. To accomplish that, I cut a sheet of posterboard to size, covered it with palm print contact paper, then cut out the hole for the window. To keep the wall covering in place on the walls, I used velcro. 



That was then.  Although I specifically designed it to be both an on-the-go, simple, portable, easy to change, folding photo backdrop . . .




as well as the base for a 2 or 3 wall room, my suggestion now would be to attach your wall covering directly to the foam core instead.


Stepping back once again and wrapping up the window installation section, here's a photo of the finished side wall with the window installed:



What's holding the window in place? Nothing more than a snug fit. (But not so snug that I can't easily pop it out it out and use it elsewhere.) These windows may look heavy, but they're not, which makes them ideal for an application like this one. 


Now it's time to move on to assembly. Here's where those ‘T' pins come into play. To attach your side wall (or walls), stand the back wall/floor on end and put a side wall on top of it making sure they line up properly. Next, push a 'T' pin straight down through both sections of foam core.



I used five ‘T’ pins total, but you can use more if you want to. Although it's not as durable as wood, it can be broken down and stored and then reassembled very easily. (Tip: after you've disassembled your room, highlight all the pin holes with a magic marker so that they're easy to find and line up for reassembly.) If you create several different walls and you coordinate carefully, you can mix and match them. Add windows and doorways in a snap or take them away just as quickly. For even more variety in size and room style, instead of scoring and folding the foam core to create an attached back wall/floor combo, cut your walls out as separate sections and then assemble them with 'T' pins either with or without a foam core floor. (Tip: An 18" high wall is a nice height for 11 1/2" size dolls.)    


For a fast, easy and versatile floor that you can use anywhere, cut a piece of posterboard to size and cover BOTH sides with contact paper. Marble on one side, wood on the other. Or black and white tile on one side, granite on the other, etc. Alternatively, scan, reduce and print out human size floor tiles, use stone print scrapbook paper (click here: for a ready to print computer scan of it). Use velour or inexpensive velvet fabric as carpeting. 


Here's a photo of what the finished wall looks like when attached to the (unfinished) back wall/floor base combo. If you're going to add baseboard or chair rail molding -- be it permanent or temporary -- wait until after the room is assembled to do it.



Here's an old photo with more of that palm print contact paper added to the back wall:



And, last but not least, here it is in its not ever likely to be finished form, the second diorama I ever created which I dubbed: 'Kurt's Den':



Did you notice the gap along left corner? When I first started, I didn't know enough to use ‘T’ pins to hold the walls together, so for that diorama, the left wall is supported by nothing more than a well hidden coffee cup. :-)




That  wraps up today's discussion. As always, here’s hoping you found it useful, inspiring and FUN!


Until next time . . .


Best Wishes,

Audrey D. 

Diva Details

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