WHAT TO KNOW ABOUT YOUR FLAT ROOF BLISTERING – FAMILY ROOFING

Posted on by David Reid

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At Family Roofing, we take great pride in our experience, expertise, quality and customer service. It is our mission to provide excellent workmanship and complete customer satisfaction from start to completion of a project. Our reputation is based on service, safety and quality, regardless of how large or small the job.

 

WHAT TO KNOW ABOUT YOUR FLAT ROOF BLISTERING

As weather changes from season to season, it’s important to keep up with your maintenance plan to keep your roof in working order.  With weather changes, roof blisters may appear on your flat roof.  While roof blisters may not need immediate attention, if left unmonitored, they could lead to saturated insulation and a damaged membrane.  Roof blisters are not limited to one type of roof system.  Roof systems with membranes are more prone to blistering because blisters are formed by gaps between the membrane plies or between the underlying substrate and the membrane.

WHAT IS A ROOF BLISTER?

A roof blister is a pocket of air trapped between the plies of a built-up or modified bitumen roof membrane.  In asphalt shingles, blisters usually contain asphalt volatile gas formed by overheating the asphalt in the shingle.  Flat roof blisters typically start as lamination voids within the system and grow larger over time due to continuous cycles of thermal expansion and contraction of the water vapor and other gasses inside the blister.

A roof blister is a raised area where there is a loss of adhesion of the roof.  This area can fill up with air or water to form a blister – which looks like a bubble on your roof.  If left untreated, a blister can grow larger and allow more moisture to get in so that the problem gets worse until more extensive repairs and possible replacement is necessary…unless it pops!

Roof blisters can be caused by any number of problems:

  • Moisture

  • Poor Installation

  • Poor Ventilation

When air or water is trapped in a blister, the weather can cause the blister to grow on a daily basis.  Warm weather will cause the water or air to expand during the day. The cool temperature will cause the trapped water or air to contract at night.

HOW TO PREVENT ROOF BLISTERS

KEEP DRY

 The number one rule for preventing roof blisters is to use dry materials in dry settings.  If your contractor says they need more time for the right weather or for your facility roof to dry out after bad weather, ensure they get that time.

PROPER INSTALLATION

 Another blister prevention tip is to make sure your materials have firm contact between them for the adhesion to work properly.

  • Install the insulation board snugly to substrate

  • Clean the work area of dust and other contaminants

  • Allow proper ventilation for the new roof system

REGULAR INSPECTIONS

 Whether you have a new roof or your roof is a few years old, it’s important to have a maintenance contract with a local roofing contractor. A maintenance contract will ensure your roof is regularly inspected, and any damage will be addressed before it causes major damage.

HOW TO FIX ROOF BLISTERS

Unless the roof blister falls under this list of characteristics, you may be fine with leaving your blisters alone:

  • Loss of gravel, granules, or another surfacing

  • Membrane deterioration

  • Blisters in seams that have reduced lap coverage

  • Blisters that have breaks that can admit moisture

  • Blisters that have fatigue cracking around the circumference

  • Blisters that occur in areas of high traffic

If your blister needs to be repaired, it’s best to hire a contractor to perform the repair properly.  If your roof is still under warranty, call the contractor that installed your roof to see what they can do to help you.

There are a few ways a contractor will repair a blister:

  1. Membrane roof – Cut away the membrane that has lost adhesion, replace any wet insulation with like material, and replace the membrane with overlapping edges at least 6 inches wide.

  1. Bitumen roof – If the membrane is in good condition, your contractor can simply cut an X shape into the blister to access the layer underneath. If the membrane is damaged, your contractor will need to replace the entire damaged area.

Effect of Roof Blisters on Roof Lifespan

Blisters tend to shorten the life of your roof.  By stretching the surface of the roofing material, they lead to the loss of a roof’s protective granules or gravel surfacing at the blister location, which results in accelerated UV damage to the membrane or shingle.  They cause protective roof coatings to crack, delaminate, and fall off.  A roof blister in a flat (low-slope) roof system will not necessarily compromise the integrity of the roof.  If the protective roof surfacing over a blister remains intact (which does sometimes happen) and the roof blister does not grow large enough to compromise roof seams, laps, or flashings, the blister can be harmless.

What Can You Do About This Issue? 

Choose a Dependable Roofing Contractor

Hiring a reputable contractor for your roof replacement is one of the best ways to avoid blisters on your flat roof.  Reliable professionals will install your new roof according to the manufacturer’s specifications.  Regardless of the kind of roof you have, proper installation can help it last long.

Schedule Routine Maintenance

Routine inspections and maintenance can contribute to the longevity of your flat roof.  They let roofers catch and fix issues before they require costly repairs. Properly caring for your roof can also ensure your home and its occupants remain safe.

Minimize Foot Traffic

Restricting access to your flat roof is vital if it already has blisters.  It’s even more crucial to limit foot traffic when it’s hot outside.  When someone accidentally steps on the blisters, they can burst, increasing the risk of water damage to your roof and the rest of your property.