Maryland does not really get a hard winter. What it gets is dozens of freeze-thaw
cycles between December and March, and that cycling — not the temperature —
is what takes roofs apart here. Water gets into a gap, freezes, expands, opens the gap
slightly, and does it again the following week.
That makes autumn the useful time to look. Here is what is actually worth checking
while it is still pleasant to be outside.
1. The gutters, and specifically the back edge
Blocked gutters are the most common contributor to ice dams, because water that
cannot drain sits at the eave and freezes there. Clear them before the leaves finish
falling and again after.
While you are there, look at the back edge. If water has been overflowing
behind the gutter rather than in front of it, the fascia board underneath is what has
been getting wet all year, and you will not see that from the ground.
2. The soffit vents, which are probably blocked
Ridge ventilation only works if air can get in at the bottom. On the mid-century
houses across Pikesville, Towson and the county suburbs, the usual problem is
insulation that has been pushed out into the eaves over the years and is now sitting
against the soffit.
The result is a warm roof deck, which melts snow, which refreezes at the cold eave.
Ice dams are a heat problem before they are a roofing
problem, and this is where most of them start.
3. Flashing at chimneys and walls
The junctions are where roofs leak, and freeze-thaw works on them harder than on
anything else. If a previous repair is a bead of sealant over a joint, treat that as a
countdown rather than a fix — sealant has a service life of a few years and
properly installed flashing does not depend on it.
4. Anything overhanging the roof
Limbs that touch or nearly touch will move in a winter storm, and a branch dragging
across shingles for one windy night removes a lot of granules. It is also the single
easiest thing on this list to deal with.
5. The attic, on a cold morning
This is the check almost nobody does and it tells you the most. Go up on a cold day
with a torch and look for daylight, for staining on the underside of the decking, for
damp or compressed insulation, and for frost on the nail points.
Frost on nails means warm moist air is reaching the deck, which is the same condition
that produces ice dams. Bathroom and kitchen fans venting into the attic rather than out
through the roof are a common culprit on houses of this era, and they produce damp that
looks exactly like a leak without any water coming through the roof at all.
What not to do once winter arrives
Do not climb up to chip ice off the eaves. People fall doing it, and hacking at ice
with a tool damages the shingles and flashing underneath. If snow is the problem, a roof
rake used from the ground on the lower few feet is the safer answer.
And if water does start coming in, call rather than wait. Water damage compounds for
as long as water keeps arriving, and temporary
protection is the cheapest thing in the whole sequence.
If you want a second pair of eyes on it before winter, our
inspection is free, we go up rather than looking from the
driveway, and you keep the photographs whether or not you ever hire us.