Synthetic Underlayment Installation

What This Service Involves

Synthetic underlayment is engineered from woven polymer rather than asphalt-saturated paper, and that difference matters enormously in a climate that sees rain more than half the year. Unlike felt, it will not wrinkle, absorb water, or tear when a project sits partially exposed during an unexpected shower. Its high tensile strength and slip-resistant surface also make steep Seattle-area roofs safer to work on and far more durable once covered. We fasten it with cap nails to manufacturer spec so it lies flat and locks out moisture for the full life of the roof above it.

Benefits

Repels water instead of soaking it up like traditional felt in wet weather; Resists tearing and wrinkling during multi-day installs common in rainy stretches; Lighter weight and larger rolls mean faster, tighter coverage of the deck; Slip-resistant walking surface adds safety on steep, damp roof pitches; UV tolerance allows longer exposure if roofing is delayed by a storm

Our Process

1) Remove old covering and evaluate the deck for moisture damage; 2) Install drip edge and eave details to control runoff; 3) Fasten synthetic sheets with cap nails at spec overlaps working up the slope; 4) Detail valleys, walls, and penetrations before the final roof layer is applied

What Affects the Cost

Square footage and layout of the roof surface; Brand and tier of synthetic product chosen; Cap-nail fastening density required by the manufacturer; Number of valleys, penetrations, and wall transitions to detail; Steepness and height of the roof affecting install pace

Best Time of Year

Its resistance to moisture makes synthetic underlayment ideal for our wet months, so it can be installed confidently even in the shoulder seasons between storms.