The Effects of Heat on Building Materials Explained

Published Categorized as Building Materials
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As the regular pace of the world picks back up again, homeowners, builders, and renovators notice a problem. Though demand for homes and renovations has never been higher, standard building materials are in short supply. Before building or renovating a home, you must know what effect the moderate heat of the day will have on the quality of your materials.

Heat causes building materials to change in size and lose natural moisture. From there, the objects either retain that heat or quickly lose it, depending on their makeup. Because the materials used differ in substance, the heat will affect most materials differently.

In this article, I’ll be discussing the most common building materials and the changes they experience due to the average heat of the sun. Read on to learn the science behind why building materials change in the heat and what you can do about it!

Why Do Materials Change in the Heat?

It may seem odd that building materials are so easily altered by the heat of the sun, significantly if you’ve grown up in a warm climate yourself. The truth is, all materials experience change when exposed to heat, even you!

Materials change in the heat because all heat represents energy, and when it transfers into any material, the molecules react to it via vibration. As the molecules gain speed, the substance itself reacts as a whole by exhibiting mild changes.

The best example to demonstrate this phenomenon is water. When you expose water to heat, the molecules in the water receive that energy and react by visibly moving. With enough movement and heat, you can see the water begin first to boil, then transform into steam.

In the same way, the water in your natural building supplies will eventually react by transforming into steam and drying as well!

All materials are made of a unique combination of atoms and molecules. Depending on the makeup of the material itself, it will experience more or fewer amounts of change.

For example, you are far more likely to see quick, visible changes in a material like vinyl than ones like concrete or brick. This is because the makeup of those materials absorbs more energy before changing.

Common Building Materials Affected by the Heat

Keep reading to learn more about how different building materials react to heat.


If you know anything about construction, you already know how vital it is to account for heat when using large amounts of timber. In fact, this need is prevalent enough that there is an architectural term for it: thermal movement.

In general, timber reacts to heat by losing moisture. This natural moisture loss causes the material itself to shrink in mass, growing smaller depending on the amount of heat to which the timber is exposed.

This shrinkage can also be affected by the wood grain, causing some timber to grow marginally shorter while others get thinner.

This thermal movement isn’t a problem for most construction projects, but you’ll need to think ahead if creating a wood-framed house.

While planning for thermal movement isn’t much of a concern with other materials, you’ll need to consider it when using large amounts of timber.

Plastics and Vinyl

Of all the building materials, those created using a plastic or vinyl base are among the most likely to be impacted by heat.

When exposed to heat, the chemical components of plastics and vinyl break down. The result is a material that is far stretchier and weaker than you’d likely prefer. In extreme cases, they can even melt!

This means you’ll want to be extremely careful with how much heat you expose your vinyl pool liner to, especially before filling the pool itself with water.

While plastics may not be the leading building supply to most projects, they make up more materials than you might imagine.


Whether you’re talking about the insulation in your attic or the lining of your windows, be aware that heat will affect it.

It feels ironic. Isn’t insulation supposed to keep heat out, after all? Though this is true, most insulating materials are actually made from forms of plastic. As a result, they will eventually break down over time.

This is an inconvenience to be sure, but it is hardly a tragedy! Be aware of the issue and get ahead of it.

Understand that eventually, the insulation in your attic, windowsills, door frames, and other exposed parts of your home will need replacing. You’ll know it’s time for a quick fix whenever you notice the material growing gummy or brittle.


Lastly, we come to one of the most common building materials of all: bricks.

Brick and cement react to the heat of the sun by absorbing it. Bricks are high in what scientists refer to as thermal mass. As such, they have a fantastic ability to retain heat; a brick laid in the sun all day will still feel warm to the touch hours after the sun has set.

While other building materials weaken due to heat exposure, brick and concrete generally maintain their form. In fact, it even has some benefits! The intense heat retention abilities make any structure built from brick or concrete easier to control in terms of temperature.

The high thermal mass means that they’ll absorb much of the midday heat and allow its inhabitants to enjoy the benefits when night chills arrive.

Similarly, brick is a fantastic way to trap indoor temperatures, preventing them from escaping and keeping your home comfortable.

By building your home with the right amount of insulation and brick, you can guarantee a sturdy structure built to withstand a wide variety of heat fluctuations!


Whether or not the changes are immediate or take far more time and energy, all materials can be changed by exposure to high temperatures. Building materials are no exception to the rule!

The best thing you can do for your own well-being and your home’s well-being is to understand the way your building supplies will inevitably act in the heat, plan for those circumstances, and know how to make repairs when necessary.


By Giovanni Valle

Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.

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