Roof Systems
Standing Seam Metal Roofing in Federal Way, WA
On a standing seam job, the superintendent walks the deck with the panel layout in hand. A standing seam roof is a field of long metal panels, joined at raised seams that sit above the water line and are crimped or snapped together, and held to the structure by concealed clips. There are no exposed fasteners in the field. That makes the layout the most important drawing on a Federal Way, WA job: where each panel starts, where it ends, where the seams fall and where the penetrations cut through.
From there the steps run in order: substrate or deck check, underlayment, clip layout, panel pick, panel set, seam closing, flashing and a closeout walk. Panels do not wait for good weather the way a membrane can, so the plan is set by when they can be handled and set.
What sits under the panels?
Standing seam can go over a solid deck with an underlayment, or over open framing with insulation and a liner system, depending on the building. On a solid deck, a self-adhered or mechanically attached underlayment guards against leaks at the seams and condensation under the metal. On a metal building, purlins carry the clips and the insulation compresses between liner and panel.
We check the substrate for flatness and fastening before panels arrive, and we mark any low spot on the plan so the underlayment and the panel line can be adjusted before the first panel is set, not after the seam machine has gone by. A deck that is wavy telegraphs through the metal; a loose deck shifts under the clips. Where we retrofit over an old roof, a framing system or sleepers raise the panels clear of the old surface and leave room for insulation. A metal roof retrofit adds a structural check to the walk, since the new weight lands on old framing.
How do clips handle thermal movement?
Metal expands and contracts with temperature. A long panel changes length through the day and the seasons, and a roof that cannot move will buckle or tear at its fasteners. Concealed clips fix the panel to the structure while letting it slide, so the roof can breathe without opening a hole. Fixed clips sit at the center of the run, and floating clips along the length allow movement.
We set clips on a laid-out grid and pull-test fasteners where the deck allows. At the eave and ridge, trim is detailed to let the panel slide beneath it without catching. A 71.6°F ceiling on monthly averages keeps the thermal swing modest in Federal Way compared with hotter regions, but the movement is still there, and the clips are sized for it. Panel runs are kept to a length the crane and the crew can handle in one pick. Roll-forming on site avoids a transport limit, and panels arrive on the roof the same day they are formed, but a tall building or a tight lot can make a crane pick the better option. The lay-down yard needs flat ground, dry cover for coils and a clear lane for the machine.
How are seams closed and penetrations flashed?
After the panels are set, a seaming machine rolls along each seam and crimps it closed. The crew leader follows the machine and checks the seam by eye and by touch. Where a seam is open or a panel has shifted, the machine passes again. At the end of a run, the seam is capped with a stop or a sealed closure so water cannot back up.
Penetrations need curbs or boots that allow the panel to move. A pipe boot clamped to a panel and sealed with butyl tape is the standard detail for small penetrations; larger units sit on a curb with a cricket upslope. Cutting a panel for a penetration is avoided where possible. Detail photographs join the closeout record, one per curb and boot and numbered to match the roof plan, so a leak report a year on traces to a single detail. A rooftop equipment curb on a metal roof is made with this movement in mind.
What do wind and rain ask of the edges?
The November 2024 bomb cyclone brought 74 mph to Enumclaw, the highest in Washington. Metal roofs catch that wind at eaves, rakes and ridges, and a loose trim piece is the first thing to peel. We set edge trim in continuous cleats with fasteners at the spacing the exposure calls for, and we lap and seal every trim joint.
Auburn takes 37.1 inches of precipitation a year, wettest in November and December, with Tacoma at about 40.8 inches across roughly 155 wet days. Wet roofs are slick, and metal on wet days is hazardous underfoot, so the crew follows fall protection rules and does not set panels in rain or on a wet deck. The day ends with every panel set and every open edge closed. A wind-damaged roof shows its trouble at the trim first.
Where does standing seam fit locally?
Standing seam suits new industrial and commercial buildings where long, simple roofs and low maintenance matter. Industrial Realty Group is building the Woodbridge industrial park on part of the roughly 400 acre former Weyerhaeuser campus in Federal Way, and the warehouse, distribution and aerospace manufacturing buildings of the Kent Valley, Auburn and Fife raise the same questions for an owner weighing a metal roof. School and civic buildings can also use it, Federal Way Public Schools being one of the city's largest employers.
Panel loads, insulation and air barriers are checked against the 2021 building code as Washington amended it and the commercial energy code. An owner in Federal Way West Campus or Fife sends the roof plan and schedule first, then both superintendents go through staging and tie-ins before a price is set.
Commercial Roofing Questions
Why choose standing seam over a membrane?
Long service life, a clean look and few penetrations in the field, provided the details are right. A membrane such as TPO suits roofs with many penetrations and low slopes. We look at slope, use and budget before recommending either.
What minimum slope does standing seam need?
Standing seam works on lower slopes than most metal panels, but each manufacturer sets its own minimum, and low-slope installs need extra sealant and care at laps. We read the product data and confirm before we price, because a roof laid below the stated slope can leak at the laps even if the panels are well made.
Does a metal roof make noise in rain?
It can, depending on the insulation and deck under it. A solid deck with insulation quiets rain well. Open-framed buildings are louder. We tell the owner what to expect for the build-up proposed, and we can add a layer of acoustic insulation where the use below calls for it.
How is condensation under the panels prevented?
By an underlayment, a vapor path that matches the building's use and insulation that fills the cavity. A wet climate and warm interiors raise the risk, so we detail it carefully and check at the ridge and eaves.
Can panels be repaired if a seam opens?
Yes. We reseam the section, seal it with butyl or sealant and replace any damaged panel or trim. We also check why it opened, because movement or fastening problems come back, and we record the clip layout near the seam so the next crew sees what was done.
Send the roof plan and the panel layout
Send the roof plan, the panel layout if one exists and the project schedule so we can walk the sequence, staging and tie-ins with your superintendent before a number goes on paper.
