MODELING: InselBric or Insulbrick Siding

American companies developed a siding to overlay wood building that provided improved insulation and fire rating.   It is called InselBric.  The Mastic Company, then of South Bend, Indiana developed “InselBric” asbestos siding in 1932.  It was widely used in the colder climates and can be seen on some older building.   InselBric is a trademarked name for a particular product sold by Mastic.  It has been spelled “Insulbrick” and other things.  It turns out that the Celotex Company created a similar product called Insulbrick.  Dennis Storzek wrote a small history on the material that was widely used by the Soo Line.

The product the Soo used was trademarked “Insulbrick”. This was a Celotex board product (Celotex is made from crushed sugar cane fiber, IIRC) 1/2″ thick with a tar and granule surface like roofing paper. It came in 16″ x 48″ sheets, and as it weathered the granules fell off the edges of the sheets first, giving a wall covered with this product a very distinctive pattern. See:

There were other fake brick products that were based on roll roofing; thin like tar paper and in rolls 3′ wide and about 33′ long, but this isn’t what the Soo used. We’ve discussed this before, and it appears that ALL the buildings covered were done in a short one or two year period about 1954 – 1956, so there wasn’t much variation.

The InselBric produce was shown in a Here is an ad 1954 Life magazine.   The product was made from wood fiber coated with asphalt and printed with a brick pattern with stone or ceramic chips to create the apperance of brick.   It was approximately 1/2″ thick.






Railroads adopted this material to improve the appearance and comfort of their elderly depots.  It did give the feeling of a more substantial and important building the than a dilapidated wood structure.

This South Oshkosh yard office on the Soo Line was sheathed with Insulbrick and a two-tone paint scheme like the prior wood sheathing likely had.


Bill Yancey has developed a very effective method for creating the Insulbrick sheathing for model structures.  I have asked Bill to describe his approach.  Here it is:

The technique I used for the Insulbrick was that I started with JTT brick material.  It is molded and not embossed so it has really crisp corners.
I did a base coat of a light tan color (TruColor Natural Wood was the closest to what I wanted).  I used a stiff bristle brush to spread black artist tube acrylic paint into all the cracks, then wiped each section down with a damp paper towel.  This will darken the base coat a bit too.
The highlighting was done with some brown fabric markers, I used 2 different colors.  I put the brown on in a predictable rather than random pattern.  Otherwise it would look more like brick rather than “fake” brick.  The dark section at the bottom I highlighted with a dark gray artist pencil.

Bill’s 1/4″ scale model is based upon a Wisconsin Central (Soo Line) standard depot.  The original design was done in board and batten sheathing.  The drawing shown below was printed in the SOO magazine which is published by the Soo Line Historical & Technical Society. 

Hope that you found this posting of some interest.




17 thoughts on “MODELING: InselBric or Insulbrick Siding

  1. Bill has done a great job modeling Insulbrick. I remember this product very clearly because it was on my Grandfather’s house in Bellwood, Illinois

  2. Hi Gene, Neat blog!

    I don’t know if you are aware, but there is a company, Clever Models, that makes patterns and textures and kits, mostly to download and print on paper.  They have Insulbrick in several colors in HO scale at least.  You might want to take a look – .  Their stuff is pretty convincing.

    Todd Sullivan(now in Rowlett, TX east of Dallas)

  3. Great article was used a lot down south too.The house in grew up had the red insualbrick on it in NC.My shop has it on the brown color!

  4. Great job of modeling Insulbrick as it was intended to look, before weathering made the individual sheets stand out, a look which took a good thirty years to developed. Since I may be the only guy who reads this who actually installed the product, I’m going to make a comment, not as criticism but in the interest of passing information on…

    Insulbrick came with corner trim, since the cut edges would not hold up to the weather. Bill attempted to model these, but they are too wide. The standard Insulbrick corner was molded from a sheet of material not quite as thick as the siding sheets, maybe 3/8″ thick, molded into a 4″ X 4″ angle. It only appeared to be the width of the end of a brick and the granules ran continuously around a slightly rounded corner; no fake mortar line on the corner. These are barely visible on the Sussex depot shown above.

    By the time Dad and I were repairing buildings covered with this material in the early sixties the product had changed to white granules in the mortar lines, which was a better representation of brick, but meant we couldn’t just patch, but had to recover entire walls, we did a couple repairs and additions to residential garages in this fashion.

  5. .I’ve seen the three-foot wide rolled imitation brick in a lot of places, including on the side of a building in Breckenridge, applied with roofing nails. The front was “architectural.” The rolled siding is not as “textural” as Insulbrick. Not sure if the usual home computer printer will print on a textured paper, but that would be great for the Clever Models product. The relief on the Insulbrick is not deep, but it is there and in a regular pattern of darks so the sheets can be joined to show a full “brick.” Closely-spaced vertical lines on some of the bricks makes them look darker than the other bricks. Interesting and common material, probably ought to be more common on model railroads set in certain locales.

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