How a Metal Roof Goes On, From Tear-Off to Ridge Cap
A metal roof performs only as well as the deck beneath it, so we strip the old surface down to bare sheathing before anything new lands. Crews pull nails with a pry bar and roofing shovel, then drop the debris into a dumpster.
- Tear-off removes old shingle, tile, or wood shake down to the plywood or OSB decking, exposing rot and soft spots.
- Deck repair replaces water-damaged sheathing, because a spongy roof deck lets fasteners pull loose under wind uplift.
- Ice-and-water shield, a self-adhered membrane, runs along the eaves and valleys first, then synthetic underlayment covers the field.
- Drip edge fastens at every eave and rake, including the verge over a gable end, to throw water clear of the fascia and into the gutter.
- Valley flashing and step flashing seal where roof planes meet, then counter-flashing and chimney flashing close the verticals.
- Panels run in staggered courses from a starter course at the eave; on a standing-seam panel the concealed clip does the holding so the fastener never pierces the metal.
- The field course stays plumb so panels track straight to the ridge cap, where ridge vent pairs with soffit vent or an attic fan.
- Pipe boots, vent boots, and any skylight curb get hand-sealed with a quality sealant before we call the roof done.
On a shingle section we run an air compressor and nail gun, setting ring-shank nails so head lap stays consistent. A batten or counterbatten grid can lift metal panels off the substrate for drainage and airflow.
Together the underlayment handles waterproofing at the deck while the panels handle weatherproofing above it. Every roofer on the job works to the same waterproofing standard, whether the assembly is a membrane or metal.
Materials We Spec, and Why the Metal Itself Matters
The grade of steel and the paint system decide how long a metal roof holds its color, so we spec heavier gauge panels with a PVDF or SMP finish. We also quote aluminum for homes near the fog line.
- Standing-seam steel hides its fasteners under a raised seam, so wind uplift never works a screw loose.
- Exposed-fastener panels cost less up front, but each screw sits in a rubber grommet that dries out and lets water wick under the metal panel.
- Corrugated panel stock suits sheds, barns, and a canopy or awning frame better than a house roofline.
- Stone-coated steel copies wood shake, cedar shake, clay tile, or concrete tile at a fraction of slate weight.
- Aluminum resists salt air and never rusts, which matters most on west-side rooftops.
- McElroy Metal, ATAS, and Decra publish load tables and trim profiles we can check against your building code.
- On low-slope sections we install TPO, EPDM, or PVC membrane, torch down modified bitumen over an old built-up roof, or apply a reflective roof coating where the surface is still sound.
Not every homeowner wants metal yet, and we say so plainly. Asphalt shingle, including architectural shingle and three-tab shingle, still costs less per square, and we install both.
What Our Roof Inspection Actually Checks
A roof inspection is a hands-on walk, not a glance from the curb. We ladder up, clip into a roof anchor and safety harness on steep pitch, and read every penetration before writing a roof estimate.
- Flashing condition at step flashing, apron flashing, pipe flashing, and boot flashing, where most leaks begin.
- Old mastic, roof cement, and caulk patches that have already peeled or lost their bond.
- Underlayment type, since dried tar paper or roofing felt under old shingles points to end-of-life wear.
- Granule loss on shingle surfaces and rust streaks along a panel, both signs the finish is flaking or eroding.
- Soft decking, which usually means rot and decay have reached the truss or rafter.
- A sag at the ridge or a dip at the hip, which can signal a settled joist, purlin, or ridge beam.
- Gutter and downspout flow, plus the soffit and fascia behind them where backed-up water rots wood first.
- Ventilation balance between ridge vent, soffit vent, and attic fan, since trapped moisture condenses against the vapor barrier and soaks the insulation below.
Why Santa Rosa Roofs Age Differently
Hot, dry summers bake the finish off a rooftop, and wildfire risk here makes ember-resistant assemblies worth the upgrade. Fog and morning dew then sit in every lap and seam until the sun burns it off.
Winter brings the other half. Pacific storms drive rain against the eave, and without proper drip edge or ice-and-water shield, water wicks into the sheathing and can freeze into an ice dam at the gutter line.
Pitch changes everything too. A steep gable, a mansard or gambrel face, a dormer, a chimney, or a deep overhang all shift the flashing details, so we note roof pitch on every roof estimate.
Timelines and the Things That Drive Cost
A residential tear-off and re-roof usually runs two to four days once materials land, and weather is the one variable nobody schedules around. A recover or overlay moves faster but leaves the old layer in place.
- Roof size in roofing squares, where one square covers 100 square feet of field.
- Tear-off versus recover, since a recover skips dumpster time but adds weight to the structure.
- Roof pitch and access, because a steep rooftop means more scaffold, ladder, and safety harness hours.
- Decking condition, since every sheet of plywood or OSB we replace is its own line item.
- Penetrations, because a skylight, chimney, dormer, parapet coping, or scupper drain each adds flashing work.
- Trim and finish, where snow guard, sealant, and adhesive costs land on a complicated roofline.
That combination is why the estimate from a Santa Rosa roofing contractor has to cover both halves of the year. We quote the repair and the replacement separately when the answer is genuinely close.
