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What is Tempered Hardboard?

T. L. Childree
T. L. Childree

Tempered hardboard, an engineered wood product, is made from wood fibers that have been tightly compressed together to form a solid sheet of building material. It is frequently referred to as Masonite® because it was invented by William H. Mason and originally manufactured by the Masonite Corporation. Tempered hardboard is similar to other types of fiberboard, but is usually more dense and water-resistant. This product is widely used in the construction of furniture and cabinets. It is typically manufactured in sheets that have a smooth finish on two sides and known as S2S panels. This type of hardboard is known for being both rigid and flexible at the same time.

Masonite® or tempered hardboard is manufactured by taking wood fibers coated with linseed oil and pressing them into sheet form at high temperatures. The linseed oil is added to the wood fibers to help bond them together during the manufacturing process. Unlike ordinary particleboard, hardboard products typically require no additional bonding materials in order to maintain their shape and strength. The use of linseed oil in the manufacturing process usually makes the hardboard unsuitable for painting. Tempered hardboard sheets are typically sturdier and more water-resistant than standard hardboard products.

Wood fibers are coated with linseed oil to make Masonite®.
Wood fibers are coated with linseed oil to make Masonite®.

This engineered wood product was first developed in the 1920s, and has been used for many decades as an exterior siding material for buildings and homes. The unique manufacturing process of this type of hardboard typically produces a strong, smooth sheet of construction material that is able to bend without cracking, splitting, or breaking. Although it is a very dense material, this kind of hardboard can usually be cut using common woodworking tools. Due to its flexibility, however, tempered hardboard should never be used in any type of structural application. It is typically sold in 4 feet (1.2192 meters) by 8 feet (2.4384 meters) sheets in a variety of thicknesses.

The material is also available as a prefinished product with veneers such as wood grain, Formica®, and various types of laminates including vinyl and paper. Finished hardboard panels are often used in bathrooms and kitchens because of their durability and waterproof qualities. Unfinished hardboard panels are typically used as cabinet backing and drawer bottoms. Tempered hardboard is also used for skateboard and bicycle stunt ramps because of its high degree of flexibility. It is also manufactured in a perforated form for use in certain types of commercial pegboard applications.

Discussion Comments


By the way, I was planning on using the 1/8" thick tempered wood for the outdoor signage, one side having a printed vinyl laminate covering from edge to edge. Thanks, again.


I want to make some outdoor signage using tempered wood with a vinyl overlay on one side. If you have experience with this material, can you tell me if it will last for very long while in the elements? I live in Colorado and we get all four seasons here, from 100-plus degree summers to incredibly cold winters, and really rainy days in-between.


If you are thinking of making something like a bookshelf, tempered hardboard is a great choice for the backing. It takes a bit of care when cutting it, but it can be done easily with a bit of practice.

What I like about tempered hardboard as it comes in a huge variety of stains so that you don't have to do that work yourself if you don't want to.

I also find tempered hardboard to be quite cheap, so if you make a mistake when cutting you can always just pick up another piece. I know when I worked with it for the first time I went through a bit of trial and error.


If you are an artist, making your own canvas can be easy with tempered hardboard. This material is the perfect backing for canvas and because it is so durable, can give your work a firm backing for many years.

After you have chosen a piece of hardboard, you need to put a few coats of acrylic polymer on each side to seal it. Let it dry and then you can trace the shape of the board onto canvas.

After you have traced the shape, cut the canvas giving an additional one-inch border all around.

Next apply some spray glue to one side of the board. Lay you canvas flat and carefully set the glued side down on it. Smooth it out with your hands.

Let this dry with some wax paper on it, covered by heavy books. Cut away any overlapping canvas when you're done and you will have a perfect place to create your art.

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    • Wood fibers are coated with linseed oil to make Masonite®.
      By: spline_x
      Wood fibers are coated with linseed oil to make Masonite®.