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Inspection Techniques for Surface Survival

The roof surface of your condo building is probably the most important common element under association control. Water intrusion into the interior will cause more damage or unit owner outrage than almost any other problem brought to the board’s or property manager’s attention. It bears careful consideration.

There are many types of roofing materials here in New England – roll/built-up roofing, wood shingles, metal, fiberglass shingles, etc. – but for ease of discussion, let us focus on the most common: high-slope asphalt composite shingle and low-slope membrane roof surfaces. Inspection techniques tend to be similar for all types of roofs.

Most roofs tend to last 20 to 30 years, but many factors can cause those estimates to vary. Warranties on roofs should not be confused with how long a roof will survive, as warranty is another word for pro-rated insurance coverage. Roof surface survival is more dependent on the quality and thickness of the material, skill of the installation, ventilation on the underside of the roof, and periodic maintenance than all the warranties in the world.

High-Slope Asphalt Composite Shingle

A periodic inspection by roofing professionals is always a good idea, but most roofs can be easily inspected with a little instruction and a systemic approach. The first thing to remember is climbing a ladder onto a sloping roof is the last thing you should consider. The condition of many roofs can be determined with binoculars and viewing the roof at the proper angle and time of day.

That said, the condition of a roof can often be best determined from inside, such as in the attic. The inspection should include observing the condition of the roof’s underside whether it be metal or wood product sheathing. Old and new leak stains should be noted, as well as their locations relative to roof penetrations and other reference points that will warrant further investigation during outside viewing. Attic inspections should also note the quality or lack of ventilation. All vents, including ridge, gable, and soffit vents should be clear of obstructions and mechanical vents should be operational. There should be a breeze in the attic on a windy day.

Roofs rarely leak in the open field of the roof unless shingles are blown off. Therefore, the roof inspection should focus on transition points of dissimilar materials or junctures of roofs and walls, such as dormers and chimneys. All skylights, vent pipes, and other roof penetrations should be monitored.

When on the ground, viewing the roof at an angle will help note irregularities or the first sign of aging and failure. Problems to observe on the inspection log are edge curling or other shingle movement; wavy shingle lines; cracked or missing shingle tabs; and loss of granular particles found in gutters from the shingle surface. Walking on shingle roofs showing signs of shingle movement can cause severe damage and lead to accelerated roof failure. Debris in roof valleys or valley flashing condition should always be noted. Shingles with a southern exposure will fail first. Observing the roof surface eave edge for damage from ice dam removal, rusting drip edges, and lack of a three-eighths-inch drip edge are all signs of early problems. Chimneys without crickets to divert water and ice are more susceptible to water infiltration and flashing failure.

Low-Slope Membrane Roof

Flat EPDM (black) or vinyl (white) roof membrane surfaced roofs are easier to inspect. They are also excellent candidates for thermal (infrared) scanning surveys. Issues to note are the condition of the surface coatings, punctures, cracking, alligatoring, blisters, fish mouths at seams, blocked drains, and ponding. Problematic conditions are ponding or the dried-up outline of prior ponding, which indicates poor drainage and can be a source of water infiltration. Roof membranes are designed to allow ponding for only a few days. If ponding is persistent over extended periods, the membrane will deteriorate, and seams will fail prematurely.

The heavy snow loads in New England are hard on low-slope roofs. Roofs are often cleared of snow to reduce dead load. The extra traffic on unprotected membranes can cause severe wear, especially in areas where the insulation boards beneath the membrane have their mechanical fastener heads touch the membrane’s underside causing tears.

No matter how many or what type of roof surface you may be responsible for, having a systematic way to keep track of the roof’s condition is invaluable. A maintenance log of leaks, repairs, and observations produces a very organized approach to facility maintenance. A checklist with the issues listed in this article with photos illustrating roof problems can go a long way to keep maintenance cost down and rain out.

Article written by Jack Carr, P.E., R.S., LEED-AP, Criterium Engineers
Published in Condo Media March 2021 edition
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