Attached Pergola Construction
Handis attached pergola construction puts a Western Red Cedar timber-frame or powder-coated aluminum louvered pergola against the house — ledger-bolted to the rim joist or to a structural blocking detail with a Z-flashing kit at the top, two outer-corner posts on concrete footings (smaller plans) or four posts on larger plans — from $6,000 for a 10-by-12 attached cedar build to $15,000 for a 10-by-12 attached aluminum louvered system. Attached pergolas tie the structure visually and structurally to the house. The ledger takes one side of the load — eliminating two of the four freestanding posts on smaller plans — and the pergola reads as a planned extension of the house rather than a yard feature standing alone. The trade-off is the structural building permit on every attached configuration (the structure bears live and dead load against the house), the Z-flashing detail at the top of the ledger to keep water out of the wall, and the through-bolt fastener spec into the rim joist or the structural blocking. Handis pulls the permit as the responsible builder; engineer-of-record sign-off when the jurisdiction requires it.
Service
How an Attached Pergola Build Works
Eight sequential steps from site review and permit pull through final inspection — the actual sequence we follow on every attached pergola build.
Site Review and Ledger-Bearing Layout
Tech walks the deck or patio, confirms the ledger location against the rim joist (or identifies the need for structural blocking between studs if the rim joist is not in the right plane), marks the outer-post locations, and validates the layout square against the deck edges or property lines. Layout review is the work at this stage; a mis-located ledger or a mis-located outer post is a footing dug twice and a permit revised once.
Pull the Structural Permit and Coordinate Engineer-of-Record
Handis pulls the structural building permit as the responsible builder with the jurisdiction (Seattle DCI, King County DPER, Bellevue / Redmond / Kirkland / Sammamish / Mercer Island / Issaquah / Renton / Tukwila depending on address). Engineer-of-record sign-off coordinated when the jurisdiction requires it for the wind-load and snow-load calcs. Permit lead time 1 to 4 weeks (plus 1 to 2 weeks for engineer review when required).
Power-Auger the Outer-Post Footings
Power-auger every outer-post footing to 24 to 30 inches below grade with the diameter sized to the post and load spec. Pour ready-mix concrete around a Simpson ABA or ABU post-base anchor (cedar) or the manufacturer-specified post-base (aluminum) set plumb in the wet pour. 48-hour concrete cure before the post is raised.
Open Siding for Structural Blocking (When Needed)
If the rim joist is not in the right plane for the ledger — a balloon-framed older house, a finished interior wall with no rim joist where the ledger needs to land — we open the siding course where the ledger will land, install structural blocking between the studs to give the ledger a solid bearing surface, and re-close the siding around the planned ledger.
Mount the Ledger with Z-Flashing
Ledger fastened through the siding (or through the open siding course) into the rim joist or the structural blocking with structural screws (Simpson SDWS Timber screws, FastenMaster TimberLOK, or LedgerLOK) or through-bolted carriage bolts per the engineer-of-record spec. Z-flashing kit installed at the top — tucked under the siding course above the ledger, over the top of the ledger, sealant detail at every fastener.
Raise the Outer Posts and Set the Beams
Outer cedar 6x6 posts (or aluminum posts on louvered systems) lifted onto the cured post-base anchors and plumbed against a 4-foot level on two faces. Beam set tying the ledger to the outer posts — 4x8 or 6x8 cedar on standard cedar plans (up-sized on spans over 12 feet), aluminum beam per the manufacturer spec on louvered systems.
Install Rafters (Cedar) or Louver Frame (Aluminum)
On cedar attached pergolas, 2x6 or 2x8 cedar rafters cut to length, end-detail chamfered or scalloped at the chop saw, installed with Simpson H1 or A35 hurricane ties at the structural attachment points. On aluminum louvered attached pergolas, the louver frame assembled per the manufacturer manual, individual louvers mounted, motor wiring run through the post, controller mounted, integrated gutter installed.
Schedule Inspections and Final Sign-Off
Framing inspection scheduled with the jurisdiction after the structural members are up but before any finish work that would conceal them. Final inspection scheduled after finish-detail (cedar) or motor commissioning (aluminum louvered). Handis stays on site for both inspections. Sign-off on the building permit closes the project; warranty registration filed on louvered systems for the manufacturer warranty.
Attached Pergola Pricing
Final pricing depends on material (cedar timber-frame vs aluminum louvered), plan size, manufacturer line on louvered configurations (Struxure, Renson, Equinox, Solara), whether structural blocking is needed when the rim joist is not in the right plane, and the engineer-of-record requirement for the jurisdiction. Structural permit fee and engineer-of-record fee pass through transparently as named line items. Line-voltage feed on motorized louvered configurations is invoiced separately by the licensed electrician. Request a free estimate for an accurate quote.
Tell us the footprint, the material preference (cedar or aluminum louvered), and which wall the ledger lands on — we will quote the attached build with the structural permit, the engineer-of-record fee (when required), and any structural-blocking add-on called out.
Why Handis for Attached Pergolas
The single most-common failure mode on attached pergolas built by a different contractor is the wall behind the ledger rotting because the Z-flashing was skipped or installed wrong. The flashing detail is a 30-minute install during the ledger mount, and skipping it is invisible from outside for 3 to 5 years until the siding is pulled and the wall sheathing is found black with rot. We install Z-flashing on every attached pergola — tucked under the siding course above the ledger, over the top of the ledger, sealant at every fastener — because the alternative is a $5,000 wall-rot callback that nobody wants. The structural permit, the engineer-of-record sign-off, the through-bolt fastener spec into the rim joist (not into siding), and the Z-flashing kit are the four details that separate an attached pergola from a problem. Handis pulls the permit and gets all four right.
Estimate
Tell us the footprint, which wall the ledger lands on (north / south / east / west facing — affects sun, wind, and rain exposure), the wall material (standard wood-frame siding, brick, stucco, stone), the material preference (Western Red Cedar or aluminum louvered), and whether the rim joist is in the right plane for the ledger (if you do not know, we will check on the first visit). We name the structural permit scope, the engineer-of-record fee when required, and any structural-blocking add-on on the estimate.
Customer Reviews
Attached pergola reviews from real Handis customers.
10x12 attached cedar pergola off the back deck in our 1962 Mercer Island split-level. Handis pulled the Mercer Island permit, through-bolted the ledger into the rim joist with the Z-flashing kit at the top to keep water out of the wall, and set the two outer posts on auger-dug footings. Cedar reads as if it has always been there. Final inspection cleared first pass.
12x14 attached cedar pergola against the south wall in Bellevue. The rim joist on our 1980s contemporary was not in the right plane for the ledger so Handis opened the siding course, installed structural blocking between the studs, and re-closed the siding around the planned ledger. Looked seamless when the cedar went up. Three years in and the wall behind the ledger is bone dry.
12x16 attached cedar against the back of our 1920s Magnolia bungalow. Engineer-of-record sign-off was required because of the wind exposure on the bluff. Handis coordinated the engineer, ran the Seattle DCI permit, and the framing inspection cleared on the first pass. The Z-flashing detail at the top of the ledger is the kind of thing you only think about when it is missing — they got it right.
10x12 attached Struxure louvered pergola off our second-floor deck in Kirkland. Engineer-stamped wind and snow load calcs through the Kirkland permit because the closed-blade roof bears real snow on a King County winter. Two days of carpentry-and-aluminum work after the footings cured, electrician sub trimmed the line-voltage feed on the same day, motor commissioned and registered before they left.
14x16 attached cedar against the back of our 1940s Ballard Craftsman. Old siding was cedar shingle and Handis treated it carefully — opened the shingle course where the ledger landed, installed structural blocking, mounted the ledger with the Z-flashing kit, and re-installed the shingle course around the ledger so the visual transition reads clean. Looks like the pergola has always been there.
Frequently Asked Questions
Common questions about Handis attached pergola construction.