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Portion of membrane roof showing
seam between membrane sections
(click image for larger version) |
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Membrane or built-up roof covers are most frequently used on roofs that have a very low
slope, usually less than about 2-inches of drop for every 12-inches of length. In homes,
these low pitch roofs are usually covered with either a membrane that is glued to the roof
sheathing or by layers of felt and tar with a gravel placed on top to protect the felt
and tar. In most cases, when a membrane is used, it will be covered with a granular
surface that looks similar to the surface of asphalt shingles. These granules help to
protect the membrane from degradation caused by ultraviolet light from the sun. Low
slope roofs are notorious for leaking because the water doesn't tend to run off as
quickly so it has a greater opportunity to work its way through any cracks or splits in
the roof cover. Cracks and splits develop over time as the roof cover expands and
contracts at a different rate from the contraction and expansion of the deck.
If you don't have a license to climb a ladder or your spouse or friends
have told you that you have no business on a ladder, you can try
binoculars or skip to Get an Expert Opinion.
There are reasons why roofers have extremely high workers compensation
rates (see Ladder Safety Tips).
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As you read through the information on roofs, some of the terms
used may not be familiar to you. You can click on
Roofing Concepts and Terms to access
a list of definitions that may be helpful.
Inspect the roof surface: Print out and use the
Checklist for Membrane or Built-Up Roof Evaluation.
From the top of your roof: Look for cracks, holes, gaps, buckling of the roof
cover, areas where water doesn't run off (ponding), and areas where most of the surface
granules or gravel cover are missing. These signs of aging are indicators that your
low-slope roof is likely to leak during a hurricane. Check around all pipes, vents or
anywhere that something sticks up through the roof membrane. The flashing around these
items should be sealed to sides of the item that sticks up through the roof, with no
gaps or cracks. Check areas where the low-slope roof connects with any vertical walls
or chimneys to make sure that the flashing in these areas is well sealed to the vertical
wall. Check the edges of the roof to ensure that the membrane is well anchored around
the edges and that any flashing is well attached to the fascia boards. Note if any of
the flashing is rusted, torn or damaged. If a membrane roof cover is used, check all
joints or seams between pieces of the membrane looking for any blistering, separations,
buckling or areas where the layers are not sealed together. Make sure that drainage
from the roof is not blocked, clean out any gutters that run along the edge of the
low-slope roof.
From inside your attic: Chances are that there is little or no access to the air
space under your low slope roof so there is usually little point in trying to peer up
into this area.
Inside your house: Look for cracked paint, discolored gypsum board, and peeling
wallpaper as signs of damaged roof areas. However, be aware that another cause of stains
on a ceiling can come from air conditioning ducts that sweat, i.e. drops of water from
condensation that forms on the ducts in a hot humid attic.
Get an Expert Opinion: If you are
not able to make the inspection yourself, get a reputable roofer or
home inspector to evaluate your roof. (Check with neighbors and friends
for referrals and check with the Better Business Bureau).
Checklist for Membrane or Built-Up Roof Evaluation
What can I do about my membrane or built-up roof?
Back to main roofing page
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