Icicles in March and a stain by the wall: why the edge goes first

The state's residential code requires an ice barrier on shingle roofs where ice has formed along the eaves and backed water up under the roofing. Ask your local office or your roofer how the rule applies at your address. Two cemented layers of underlayment will do, as will a single self-adhering membrane.

Measured from the lowest edge, it must reach 24 inches or more past the outside wall line. On a roof pitched eight in twelve or more, it climbs 36 inches up the slope as well. Ask the roofer to name the product and give the reach in writing, because a short barrier is cheaper and it is the reach that does the job.

A drip edge is a metal strip along the eave. The code requires one at the eaves and rakes of shingle roofs, overlapped 2 inches at joints, extending a quarter inch below the sheathing and 2 inches back onto the deck. At the eave the underlayment goes over it, and at the rake it goes under.

It is a small line item and it is easy to drop from an estimate. Ask for it by name, and ask whether it is new or reused.

The deck is the wood under the shingles. Water that backs up at the edge reaches it first, and wet wood can stop holding a nail. You cannot see the deck from the ground, and a roofer sees it only when the old roof is off. That is why a replacement is the one day anyone checks it all the way along.

The code bars a new roof over a covering that is soaked or too deteriorated to be a base, and over two or more layers. So ask for a price per sheet or board for bad wood, in the estimate, before the work starts. That turns a surprise into a number.

Federal housing guidance sets 20 years as the useful life of an asphalt shingle roof. Treat it as a planning number and not a verdict on your roof. NIST research says shingles face heat, thermal cycling, sunlight and freeze-thaw, plus wind and hail, and that these can weaken them. A roof can age well on one slope and badly along one edge.

This is why the question "how old is it" often matters less than "when does it leak and what is the deck like". Tell the roofer when the stain appears, and ask what they see at the eave.

The same Department of Energy guide gives the upstream fix in order: air seal the ceiling, then insulate the attic, then ventilate the roof. That is attic work, and it is a separate job from the roof covering. Ask your roofer who would do it, so that a new eave does not have to hold back the same melt.

You can learn a good deal without a ladder. Walk the edge of the house on a bright day and look for icicles that hang in the same places every winter. Look for shingles that curl or lift in the first row above the lowest edge, for stains on the soffit and for staining on the siding below the edge.

Inside, look for a ceiling stain or peeling paint near an outside wall. Photograph each one with a date. Tell the roofer where both are, and let them decide which part of the edge to open first.

An ice barrier already stuck to the deck may stay, with a new layer over it, only when the sheathing is sound. Both makers must allow it too. That is a narrow exception. If a roofer proposes to leave an old barrier in place, ask which makers allowed it and how the deck was judged sound.

The county hazard plan scores winter weather as the top weather hazard here, and notes that a property in poor condition can suffer roof damage when ice and snow build up. In the Town of Clay it also names ice-loaded trees falling on houses, so if you live there, ask the roofer about limbs near the roof as well as the edge.

Sometimes the field of the roof is sound and the edge is the problem. A roofer may suggest redoing the first few feet with a proper ice barrier and a new drip edge, and leave the rest. Other times the wood is wet along the whole edge and the answer is larger.

Either way, ask for the eave job to be priced on its own, and for any larger job to be priced beside it. Read our ice dam page for what that estimate should list, or send us your photos and ask for a visit.