5 Roof Threats To Consider Before Choosing Your Roof Material

Jerry Beall on Sep 21, 2015 9:30:00 AM

Temple BethDuring a recent webinar, an attendee asked the following question:

Most of our buildings are over 50 years old with many changes in plane on the surface. Most are BUR with mineral cap sheets. What would be a better system when replaced?

Our answer: When it comes to a replacement system we recommend that you first focus on the solution, as the purpose of the membrane is to protect that solution. There are many options afforded you when using a KEE membrane to solve the issues. Flexibility and versatility are needed to traverse multiple planes and I assume multiple deck types. You may also have circumstance where you can just cover the existing cap sheets. I would recommend that you enlist the services of one of our representatives for a free inspection and analysis.

But let’s go back a minute; understanding the technologies behind your roofing material and how those technologies withstand common threats to roof performance is crucial. Before you select a roofing material for your new roof, use this chart to understand the pros and cons of how each material measures up against threats for failure.

 

BUR

Modified Bitumen

EPDM

TPO

PVC

KEE

UV

UV breaks down the bitumen - leading to cracking and crazing.

UV breaks down the polymers - leading to cracking and crazing.

Good UV resistance - extreme UV and heat can dry out the oils however. Seam adhesives can also degrade over time.

Stabilizers are added to increase UV resistance, but it can negatively impact fire resistance - hard balance to find.

UV rays break down PVC - plasticizer bond allowing plasticizer to migrate resulting in cracking and difficult repair.

Excellent UV resistance. Due to ‘miscible’ polymer, additives are easily accepted and bond breakdown is prevented.

Impact / Puncture

Starts out with good resistance, but as UV breaks down roof the impact / puncture resistance decreases.

Starts out with good resistance, but as UV breaks down roof the impact / puncture resistance decreases.

Non-reinforced has poor puncture resistance but good impact resistance. 

Fair puncture resistance and impact strength.

Fair puncture resistance and impact strength.

Excellent puncture and impact resistance. Adding thickness can increase dynamic impact resistance.

Chemical

Chemicals soften bitumen and thus accelerates breakdown.

Chemicals deteriorate modifiers and then the bitumen itself accelerating breakdown.

Poor resistance; long-term exposure can lead to eventual softening and deterioration.

Minimal chemical resistance; known for swelling.

Good chemical resistance; some chemicals accelerate breakdown of PVC - plasticizer bond though.

Excellent chemical resistance; inherent to product makeup.

Wind

Fair to moderate resistance. Weakness is “peel” resistance to first ply.

Moderate to good resistance because it can be mechanically fastened.

Poor to fair resistance; not heavy duty fabric.

Fair to good resistance; not heavy duty fabric. Unproven long term adhesives that add risk.

Good to excellent resistance due to some heavier duty base fabrics and proven adhesives.

Good to excellent resistance; heavy duty base fabric and proven adhesives.

Fire

Poor resistance and high maintenance costs to protect. Aggregate required to restrict flame spread.

Poor resistance and high maintenance costs to protect. Aggregate required to restrict flame spread

Poor resistance; Flame retardant versions significantly increase cost

Poor resistance; retardants difficult to add without effecting other properties.

Good to excellent resistance; Flame retardants easily compound and inherent flame suppressant chlorine.

Good to excellent resistance; retardants easily compound and inherent flame suppressant chlorine.

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