Skip to Content

Mainely Roofing

Mainely Roofing

Article written by Jack Carr, P.E., R.S., LEED AP, Criterium Engineers
Published in Condo Media, May 2011

YOU were elected chair of the Building Maintenance Committee, so now what do you do? What are your priorities? That's easy. Ensure the buildings are watertight and the building envelope is intact after this last winter. Where shonld you start first? That also is easy, because in spring our minds naturally turn to thoughts of ... roofs.
 
Here in New England there are many types of roofing materials, but, for ease of discussion, let's focus on high-slope asphalt composite shingle and low-slope rubber membrane roofing. Inspection techniques tend to be generic to all types of roofs.
 
Most roofs tend to last 20 to 30 years, but many factors can cause those estimates to vary. Warranties should not be confused with how long a roof will survive, as warranty is another word for pro-rated insurance. Roof 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. A periodic inspection by roofing professionals is always a good idea, but most roofs can be easily inspected with a little instruction and a systematic approach. First, remember that getting onto a sloping roof or climbing a ladder may be the last thing you should consider. Many roofs can have their condition determined with binoculars and viewing the roof from the proper angle and time of day.

Inspection Inside and Out

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 is metal or wood product sheathing. Old and new leak stains can be noted, as well as their locations relative to roof penetrations and other reference points for further investigation during outside viewing. Attic inspections also should note the quality or lack of ventilation. All vents, such as ridge, gable and soffit, should be clear of obstructions, and mechanical vents should be operational. There should be a breeze in the attic on a windy day. A poorly vented attic can reduce the life of a composite shingle roof by half, as the excess heat will breakdown the asphalt components of the shingle causing premature failure.
 
Roofs rarely leal, in the open field of the roof unless shingles are blown off. Therefore, the majority of 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 pipe and other roof penetrations should be monitored, When on the ground, viewing the roof at an angle can easily assist in noting irregularities or the first sign of aging and failure. Conditions to look for include edge curling of the shingles, fish mouths, wavy shingle lines, cracked or missing shingle tabs and loss of granular particles from the shingle surface. Walking on shingle roofs showing signs of shingle movement can cause severe damage and accelerated roof failure. Debris in roof valleys or condition of the valley flashing should always be noted. Shingles with a southern exposure will  fail first. Observing the roof eave edge for damage from ice dam removal, rusting drip edges and lack of a 3IS-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.
 
Flat EPDM or vinyl roof membrane roofs are easier to inspect. Parameters to note are the condition of the coatings, punctures, cracking, alligatoring, blisters, fish mouths at seams, blocked drains and ponding. As an example, often ponding or the dried-up outline of prior ponding can be an indication ofwater infiltration sources. 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 this year were particularly hard on low-slope roofs. Often roofs had to be 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 come in contact with the membrane's underside causing tears.
 
No matter how many or what type of roof 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 approaeh 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 costs down and rain out.
 

 
© 2011 CRITERIUM ENGINEERS