Make a custom fireplace

Judy Kingsley of Chelsea, Quebec, created this tutorial for customized fireplaces carved out of builders foam insulation. "I wanted a special fireplace with rounded legs for the Witch House I made for my mother’s 80th birthday. After thinking about how to make it, I decided to carve it out of blue foam insulation, then cover it with air-drying clay. It worked beautifully!"

Builders foam (or insulation) is a product similar in consistency to "oasis," the product that the florists use for bases in arrangements. It's easy to cut using a sharp blade, and pieces can be glued together to make thicker pieces. The foam comes in 4x8-foot sheets of different thicknesses, in both pink and blue colors. It's sold in home improvement stores under a variety of brand names.

WARNING: Glues that contain solvents should never be used on foam. Solvents will dissolve the foam, releasing dangerous fumes. Don’t use hot glue directly on foam, as it will cause it to melt, releasing dangerous fumes. I have used Aleene’s Tacky Glue and Weldbond glue, with no problems.


- 6x8" piece of 1"-thick blue foam insulation
- Sharp knife or X-Acto
- Fine-tooth miter saw
- Paper and pencil
- Weldbond glue or Aleene’s Tacky Glue
- Air-drying clay
- Clay tools for sculpting (my favourite is a large plastic darning needle from the dollar store)
- Stiff brush for adding texture (such as a toothbrush)
- Brushes and acrylic paint for the stones
- Container for water

First make a pattern for your fireplace on a sheet of paper, and then trace it on to the foam.

Cut out the fireplace. It’s easiest to cut away small chunks of foam at a time, especially around curved areas.

Once the fireplace is cut out, it will look a bit rough. That's okay! Mark a line at the base of the chimney on the front of the fireplace. You will be cutting the chimney out to this line.

Draw a line on both sides to show where the curves will be cut out.

Use an X-Acto knife or a fine-toothed miter box saw to remove the front half of the chimney. To do so, cut halfway through the foam along the horizontal line at the base of the chimney.

Then starting from the top of the chimney, slice through the chimney down to the line.

Your fireplace should now look like this (side view).

If a piece of the foam breaks, just glue it back on. The whole thing will be covered with clay and it will never show.

Carve out the fireplace legs using a sharp blade. Don’t worry if it’s not exactly symmetrical - it will be covered with clay.

Have ready a small container of water, to be used if the clay starts to dry out too soon.

Roll out a piece of air-drying clay to about the thickness of a pie crust (about 1/8th of an inch thick.)

Spread glue over every part of the fireplace that you want covered with clay (see glue warning above)

Drape the clay over the fireplace, patting it down so there are no air pockets.

Trim off excess and use these bits to cover any holes in the clay. Smooth joints in the clay by dipping your fingers in water and gently brushing them over the clay.

Sculpt the individual bricks or stones in the clay before it dries. If the clay starts to dry out before you are finished, dip your fingers in water and gently brush them over the clay.

Use a stiff brush to stipple the front of the bricks and stones to give them texture. Allow to dry completely (overnight or even longer if you live in a very humid area).

Brush the dried clay with a dirty wash to tone down the colour. Let dry.

Use different coloured washes to paint the individual bricks and stones, repeating as necessary to get the colour you want. Leave the grout unpainted. Allow to dry completely.

Now it's ready to put in place! (See the photo at the top of this article.)

One of the nice things about using foam is that it allows you to carve out any shape for your fireplace. Here is an example of another fireplace. Notice the two little niches carved out for the skulls.

I painted the foam the colour I wanted the finished fireplace to be. Then, instead of clay, I covered the painted foam with a product called GOLDEN Extra Coarse Pumice Gel. To make the fireplace fit into a corner, I simply glued on a triangular piece at the back, and covered it with a wood mantle cut to fit the corner.

Here is the finished fireplace in the Witch Tower. This was my first ever roombox, started in 2006 and still in progress. It's made in a wine box. I made the interior walls separately from thin foam core and once they were finished, glued them to the inside of the box. The balcony posts are toothpicks. The doors are false doors, added to give the impression of more rooms.

This attic (home of an elderly flower seller) was a Miniature Enthusiasts of Ottawa club workshop. Each participant finished their attic the way they wanted. I made the fireplace from foam and painted it, then coated it with GOLDEN Extra Coarse Pumice Gel, and then a final coat of paint.

As you can see, the foam base can be finished with a variety of materials, such as clay, texture gels or mediums, plaster, paint, or wallpaper. There is no limit to the original fireplaces you can create using techniques like these!


Anonymous said...

This is a great tutorial! I can't wait to try it!

Wacky Pup said...

Very well done tutorial and the fireplaces you've made are great! Thanks for posting it!


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