Vinyl Deck Elasticity vs. Breaking Strength

A good roofing membrane has to be strong enough to withstand stresses and flexible enough to accommodate deck movement.

When you are comparing the properties of vinyl deck membrane options for your deck, you may encounter claims that one vinyl’s ‘Breaking Strength’ is greater than another, followed by claims that a higher rating on Breaking Strength makes it a better option.

Breaking Strength and Elasticity (also called Elongation to Break) are both measured by a tensile testing machine, which pulls a rectangular piece of the vinyl membrane at a constant rate. Breaking strength is the stress needed to break a sample. The elongation-to-break is the strain on a sample when it breaks.

We propose the more important of the 2 tests is Elasticity.

Duradek meets all Breaking Strength and Elongation requirements – it is this elasticity that allows Duradek to perform its waterproofing function for so long (we’ve seen evidence of our membrane still performing after more than 30 years!…see video below).

Elasticity in a vinyl deck membrane is extremely important.

Imagine your deck as it expands and contracts throughout the seasons as the temperatures change year after year. The deck will be moving and since the membrane is fully adhered, it needs to be able to move with the deck. That requires elasticity, not breaking strength.

So don’t be led to believe that just because one product’s ‘Breaking Strength’ is rated greater than another’s, that that means it is better suited for protecting your deck.

Download out Strength vs Elasticity Comparison (pdf).

For a great demonstration of Elasticity, we love this video from Duradek of Utah that was created to demonstrate Duradek vinyl’s excellent seam strength by towing a Ford F250 truck. This amazing visual shows not only the strength of Duradek’s heat-welded seams, but also clearly shows the excellent degree of elasticity in the membrane which is far more than will ever be needed by climate expansion and contraction issues.

When you are selecting a vinyl deck membrane, trust the proven performance of Duradek. Installed only by trained contractors, Duradek makes sure your deck waterproofing performs as intended.

Look for a Duradek installer in your area to discuss your decking project.

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