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Spray Foam Insulation

Spray Foam Insulation Shrinkage: How To Prevent It

Spray Foam Insulation Shrinkage

Anyone who remembers their secondary school physics classes will remember a basic fact: hot things expand and cold things contract.

Depending on the material in question, this can either be a very significant fact that can be very useful, such as the thermal expansion of liquid in a thermometer which causes the measured level to rise, or just an interesting piece of trivia, such as explaining the creaking of a house as the hallways cool at night.

Spray foam is no exception, depending on the temperature the foam will either expand slightly or contract and normally this is no problem. That is, until it is one…

Spray Foam Insulation Shrinkage: The Risks:

So, what are the problems that can arise? Well, firstly, if foam is too thickly applied, thermal expansion can start to put pressure where you don’t want pressure.

If anyone remembers freeze/thaw erosion from their secondary school geography classes: repeated expansion and contraction of water in the cracks puts strain on the outer layer of rock and it eventually breaks it up?

Well, repeatedly heating and cooling foam that is too tightly packed into the nooks and crannies of a loft can follow a similar principle and, well, is probably best to avoid.

Another factor is something called ‘dimensional stability’. The ins and outs of dimensional stability are fairly involved, but the blog-length summary is basically all foams will expand or contract to some extent.

The higher the dimensional stability, the less your foam will change over time and the better it will endure extreme conditions. There are four types of foam, type one being the least stable and type four being the industrial strength foam designed to endure extreme conditions.

Typically, the composition of the foam comes pre-ordered and in housing, it’s more or less a one size fits all. However, if your house has any special requirements, a high quality licenced contractor will pick up on this and make all the necessary arrangements.

Another problem of foam shrinkage occurs when the gap that the foam is supposedly filling becomes unfilled-leaving exposed areas that heat can escape from.

If foam shrinks and is no longer able to fill the intended space, it will stop acting as a water barrier. This means that you’re in for all sorts of problems with potential condensation building up in places where you do not want it.

Spray Foam Insulation Shrinkage

A competent contractor will know exactly what the house needs, both in terms of composition and dimensions, and will ensure your spray foam installation is right from the outset!

So, Is There Any Silver Lining To Spray Foam Shrinkage?

Spray foam shrinkage is a better bad thing when it does happen. Having just explained in a fair amount of detail what can go wrong, how am I going to suggest that you really have almost nothing to worry about?

Spray foam insulation is a high-quality product, so high quality contractors are more than aware of the problems that thermal expansion and contraction, and shrinkage can cause. Problems with shrinkage are almost always a result of installation being poorly planned and or executed.

For this reason, a competent contractor will know exactly what the house needs, both in terms of composition and dimensions.

If spray foam is put in properly, even on the hottest days it shouldn’t expand enough to cause any structural problems to your home. If it’s packed in properly, even on the coldest days it shouldn’t shrink enough to let a draught or any vapour through.

In terms of composition and dimensional stability, this is really one for the contractors to worry about. If the spray foam wasn’t mixed properly when it arrived, you’ll both get a replacement and if the wrong composition was used, well that’s really the contractors mistake and our problem to fix.

All in all, insulation shrinkage is something that should be avoided, but it isn’t something to worry about.

Seeking out a failproof way to prevent spray foam shrinkage from the outset? Enlist the help of the experts and get it right the first time! Simply click the button below to get started today, or talk to our team of experts direct by calling 0800 1700 636.