New construction roofing for Portland homes, ADUs and additions
Framing is up, the sheathing is on, and the rain is coming. We roof new homes, ADUs, additions and detached garages across Portland, drying in quickly and tying new roofs cleanly into existing ones.
New construction roofing in Portland covers drying in fresh sheathing with underlayment and ice and water shield, installing drip edge, flashing at walls and penetrations, balanced attic ventilation and the finished roof. For an addition, it also means weaving the new roof into the existing one. A detached ADU or garage roof commonly costs $6,840 to $15,720 in architectural asphalt.
On a new build, the roof is the step that turns an open frame into a protected structure. Every day sheathing sits exposed to Portland rain, it swells at the edges, the framing below soaks up moisture, and the drywall schedule slips. Builders and homeowners managing their own projects call us because we can dry in a roof quickly once the trusses and decking pass framing inspection, then come back to finish the surface when the rest of the trades are ready.
We work on everything from a full custom home in the West Hills to a backyard ADU in Concordia or a second story addition on a Sellwood bungalow. Small structures still deserve the same details as a whole house: ice and water shield in valleys, kick-out flashing where the roof meets a wall, and vents sized to the attic. Additions bring the extra job of matching shingles and tying the new roof into the old one so the seam never leaks. Call (503) 917-5484 to plan your roof into the build schedule.
Picking a roof for a brand new structure
New construction gives you a clean slate, so it is worth matching the material to the design and the lot.
Architectural asphalt shingles
A reliable choice for most new homes and additions. Matching the main house color line keeps an addition looking original, and asphalt is the most budget friendly finish for detached garages and ADUs.
Standing seam metal
Popular on modern ADUs, low-slope sheds and contemporary infill homes. It sheds rain and fir needles quickly, handles low pitches better than shingles and pairs easily with solar mounts later.
Low-slope membrane roofing
Flat and shallow roofs on modern additions, dormers and garages need TPO or modified bitumen rather than shingles. We use membranes rated for the pitch, with tapered insulation where water needs help draining.
Synthetic shake or slate
Composite roofing gives a new home the look of shake or slate without the upkeep. It suits upscale builds and additions on homes that already have a textured roof look.
When should a roofer join your building project?
Bringing us in at the right moment keeps the build moving and avoids costly rework.
Plans are being finalized
Roof pitch, overhang depth, vent locations and the material all affect cost and performance. A quick review before framing can catch tricky valleys, dead valleys against walls or vent spacing problems while they are still easy to change.
Trusses and sheathing are set
Once the deck is nailed and inspected, the clock starts. We aim to get underlayment and edge metal on within days so the structure is protected from the next rain before windows and siding go in.
An addition meets the old roof
Wherever new framing connects to an existing house, the roofs have to be tied together. We plan the transition, whether it is a valley, a cricket or a wall flashing, before the old shingles get cut.
ADU or garage permits are approved
Backyard ADUs are common across Portland now. As soon as the structure is framed, we can match or contrast the main house roof and handle gutters so runoff stays off the neighbor property.
Solar or skylights are planned
Skylight curbs, solar mounts and vent stacks are easiest to flash when they go in with the roof. Telling us early means penetrations get proper flashing instead of being cut in later.
How we roof a new structure from deck to ridge
Review plans and schedule
We look at the roof plan, pitch, overhangs and ventilation details, then coordinate with your builder or framer on dates. You get a written estimate covering dry in, finish roofing, flashing and any tie-in to existing roofs.
Check the deck before covering
We confirm sheathing nailing, panel gaps and edge blocking before anything goes on top. Swollen OSB edges from earlier rain get sanded or replaced so the finished shingles lie flat.
Dry in with underlayment fast
Ice and water shield goes on at eaves, valleys and low-slope areas, then synthetic underlayment over the rest, along with drip edge. At this point the structure is protected, and interior trades can safely move in.
Flash walls and penetrations
Step flashing and kick-out flashing go in at every roof to wall junction. Plumbing vents, exhaust fans and skylight curbs get boots or flashing kits. We coordinate with siding crews so counterflashing laps correctly.
Install the finished roof
Shingles, metal or other finish materials go on with starter strip, proper nailing and ridge vents matched to the soffit intake. On additions, new courses are woven into the existing roof so the line runs straight.
Gutters and final inspection
We hang gutters and downspouts sized to the roof area, clean the site of debris and nails, and walk the roof with you or your builder. Photos of every stage go into your project file.
Materials for new construction roofing come from manufacturers such as Malarkey, GAF, Owens Corning, CertainTeed, Carlisle and Velux, chosen for the job rather than the logo.
What does new construction roofing cost in Portland?
New roofs skip tear-off, so the cost per square is lower than a reroof. Complexity, height and material set the final number.
| Work | Typical Portland range |
|---|---|
| Detached ADU or garage, architectural asphaltper structure | $6,840 to $15,720 |
| Room addition with tie-in to existing roofper addition | $4,960 to $13,480 |
| New single family home, architectural asphaltper home | $12,780 to $28,640 |
| Standing seam metal on new buildper sq ft | $11.85 to $19.40 |
| Dry in only, underlayment and edge metalper sq ft | $1.65 to $2.85 |
Expect these ranges to move with the plan set and site. After we review drawings or walk the framed roof, you receive a written estimate with firm pricing.
What moves the price:
- Roof area and pitch
- Material and color line
- Tie-in to an existing roof
- Valleys, dormers and penetrations
- Site access and staging room
- Schedule and return trips
Building and roofing new spaces around Portland
Portland lots are getting fuller. ADUs behind older homes in Concordia, Arbor Lodge and Woodstock, pop-top second stories in Sellwood-Moreland, and new infill houses on narrow lots all need roofs that fit tight spaces and nearby neighbors. Small structures often sit under big street trees, so we plan for heavy needle and leaf fall with properly sized gutters and slopes that shed debris. On narrow lots we stage materials carefully because there is often no room for a dump trailer beside the house.
Beyond the city, new subdivisions in Happy Valley, Hillsboro and Sherwood are still going up, and our wet season is the main enemy of an open frame. We plan dry in so sheathing sees as little rain as possible, especially through late fall. Homes on the Tualatin Hills and West Hills slopes also face more wind, so we follow the high-wind nailing patterns and use sealed starter strips along every edge.
Why builders and homeowners schedule us for new roofs
Fast dry in after framing
We prioritize getting underlayment down quickly once a deck is ready, so the structure is protected from rain and interior trades can start on time.
Clean tie-ins on additions
Weaving new shingles into an old roof is where many additions leak. We plan the transition carefully and match color lines as closely as current products allow.
Details that pass the first time
Kick-out flashing, ventilation balance and proper nailing are done to manufacturer specs, helping your project move through final inspection without callbacks to fix the roof.
New Construction Roofing questions from Portland homeowners
How soon after framing can you roof a new Portland ADU?
Once the trusses and sheathing are installed and the framing inspection is passed, we can usually schedule dry in within a few days. Getting underlayment on quickly matters here, because our rain soaks exposed sheathing fast. The finished roof can follow right away or wait for other trades.
Can you match the shingles on my house for a new addition?
We match the manufacturer and color line when it is still made, which gives a close match. Older shingles fade over time, so new ones may look slightly different at first. On some homes, reroofing the slope where the addition connects gives the cleanest overall look.
Do new construction roofs need ice and water shield in Portland?
Yes, in the right places. We install self-adhering ice and water shield along the eaves, in every valley, around penetrations and on any low-slope sections. Portland does not see heavy snow often, but ice events and wind-driven rain still push water under shingles at these weak points.
Should a new garage roof in Portland have gutters?
Almost always. Without gutters, rain from the roof splashes against the walls, soaks the foundation and can flow toward a neighbor property. We size gutters and downspouts to the roof area and the tree cover so the garage stays dry year round.
What roofing works on a low-slope ADU roof in Portland?
Shingles need a minimum pitch to shed water. Below that, we use single ply membranes like TPO, modified bitumen or standing seam metal rated for low slopes. These materials keep water out even when it moves slowly across the roof.
Where we do this work most
We cover the whole metro. These are the places we are on roofs most often:
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