Patio Door & French Door Installation in Portland, OR

Hinged French Doors. Multi-Panel Folding Doors. Patio Door Replacement. Proper Flashing at Every Installation — Not Just a Door in a Hole. Licensed OR #241979.

Group of five people standing outdoors in front of a house and trees, wearing casual and work clothing, smiling at the camera.

Patio and French doors are one of the most common sources of water damage in Pacific Northwest homes. A door improperly flashed at the head, without a sill pan at the base, or with a failed threshold seal, allows water to enter the wall cavity and saturate the subfloor framing below the opening. VResh Construction installs all patio and French door types with the same moisture management discipline we apply to window installations — proper drainage plane integration, a sill pan at the base, head flashing above, and complete weatherstripping and threshold sealing.

Patio and French Door Types We Install

Hinged French Doors

French doors — two outward or inward-swinging hinged doors with divided lights or full-glass panels — add significant visual character to a home's indoor-outdoor transition. They provide a wider, clearer opening than standard sliding doors for furniture movement and are preferred for their traditional aesthetic.

French doors are more complex to weatherstrip than sliding doors due to the center meeting stile — the vertical member where the two doors meet. Proper installation includes multi-point locking hardware and astragal seals at the meeting stile to prevent air and water infiltration at the center.

Common brands: Milgard, Marvin, Andersen, Jeld-Wen, Therma-Tru. We install all major brands and recommend products based on the homeowner's budget, aesthetic preferences, and energy-efficiency priorities.

Multi-Panel Folding / Bifold Patio Doors

Multi-panel folding doors — sometimes called NanaWall or accordion doors — consist of 3–8 panels that fold and stack to one or both sides, creating a wide opening that effectively merges indoor and outdoor living spaces.

These doors require a structurally engineered header above the opening to carry the load previously carried by the wall framing being removed. We coordinate structural header sizing with the door manufacturer's requirements and obtain all required permits.

Folding door systems are a premium product with premium installation requirements. They are most common in high-end Portland renovations where indoor-outdoor integration is a design priority.

Patio Door Replacement (Existing Opening)

Replacing an existing patio door in the same rough opening is a common project that typically does not require structural work — but does require thorough inspection of the existing rough opening, threshold, and surrounding framing for moisture damage before the new door is installed.

We remove the existing door, inspect the rough opening and subfloor framing below the threshold (a common rot location), make any necessary repairs, and install the new door with proper sill pan flashing, head flashing, and weatherstripping.

For older sliding glass doors being replaced with new French or folding systems: rough opening modifications may be required. We assess the structural implications and permit requirements at the estimate stage.

Four men, possibly members of a security or construction team, are standing on a green lawn in a backyard. One of them is pointing at the house while the others are observing. They are dressed in casual work clothes, and one has a toolbox. The house is a light gray two-story with white-framed windows, surrounded by trees and shrubs. In the background, there is outdoor furniture and a stone grill.

(503) 272-6436 — Call or Text, Available 24/7

We answer calls and texts at any hour. For storm damage, active leaks, or structural emergencies, calling directly is the fastest path to a response.

Our Patio Door Installation Process

#
Item
What We Do — And Why It Matters
1
Rough opening assessment
Inspect the existing rough opening for moisture damage, rot, and out-of-square conditions. Check subfloor framing below the threshold — this is a high-frequency rot location on Portland homes with original patio doors installed without sill pan flashing.
2
Structural repair (if needed)
Remove and replace any compromised framing, threshold plates, or subfloor sheathing. Correct the moisture source before new installation.
3
Lead protocols (pre-1978 homes)
Test disturbed surfaces, follow containment and cleanup protocols per EPA RRP rules, and provide written documentation.
4
Sill pan installation
Install a formed sill pan at the base of the rough opening to capture any water that passes the door threshold and direct it to the exterior. This is one of the most commonly omitted steps in budget door installations.
5
Drainage plane integration
Lap the door installation into the existing WRB — housewrap or building paper. On older homes, install or replace WRB in the affected area.
6
Head flashing
Install head flashing above the door opening to direct water away from the top of the rough opening. Lap into the WRB above.
7
Door installation and leveling
Install the door unit per the manufacturer's specifications. Verify level, plumb, and square. Test all operating functions before any trim is installed.
8
Air sealing and insulation
Fill the gap between the door frame and rough opening with low-expansion foam. Complete air sealing before any trim is installed.
9
Exterior trim and caulk
Install exterior casing, properly back-primed and bedded in sealant. Caulk all exterior joints per the manufacturer's specification.
10
Interior trim and finish
Install interior casing, finishing to match existing interior trim. Hardware installation and final operation test.

Patio Door Brands We Install in Portland

Milgard — Most Common in Portland

Milgard's Tuscany and Trinsic series French doors and patio door systems are the most commonly installed patio door products in the Portland metro. Full Lifetime Warranty for the original purchaser. VResh is a Milgard Warranty Service Provider.

Milgard also manufactures Moving Glass Wall sliding systems — multi-panel configurations for larger openings.

Andersen — Premium and Wood Interior Options

Andersen 200 Series (Fibrex composite) and 400 Series (wood interior, Fibrex exterior) French and hinged patio doors. Premium option for homes where wood interior character is important.

Andersen E-Series provides the highest level of customization — any size, any divided light configuration.

Marvin — Premium Wood and Fiberglass

Marvin Elevate (Ultrex fiberglass exterior, real wood interior) and Ultimate (full wood or custom) French doors. The right choice for Portland historic homes, where matching original door character is important.

Marvin doors can be specified with exact divided light configurations to match the original Portland bungalow or four-square door profiles.

Therma-Tru and Other Brands

For fiberglass French doors, Therma-Tru has a strong Pacific Northwest track record — moisture-resistant, dimensionally stable, and available in realistic wood-grain textures.

We install all major patio door brands. If you have already selected a product, we install it. If you are still choosing, we advise.

Close-up of gold quotation marks.

Client's Talk

We have a wealth of experience working as main building contractors on all kinds of projects, big and small, from home maintenance and improvements to extensions, refurbishments and new builds.

Serving Portland Metro Area

VResh Construction provides window replacement, siding installation, roofing, dry rot repair and full exterior renovation services throughout the Portland metro area and Southwest Washington.

Portland Metro — Oregon

Portland, OR
Oak Grove, OR
Cedar Mill, OR
King City, OR
Happy Valley, OR
Clackamas, OR
Milwaukie, OR
Gresham, OR
Wood Village, OR
Scappoose, OR
Sandy, OR
Newberg, OR
Estacada, OR
Lake Oswego, OR
Beaverton, OR
Hillsboro, OR
Tigard, OR
Sherwood, OR
West Linn, OR
Oregon City, OR

Southwest Washington

Vancouver, WA
Battle Ground, WA
Woodland, WA
Camas, WA
Ridgefield, WA
Washougal, WA
Kalama, WA

Extended Service Areas

Longview, WA
Kelso, WA
Salem, OR
Seaside, OR
Lincoln City, OR
Long Beach, WA
OUR FAQS

Patio Door FAQs — Portland Homeowners

How much does French door installation cost in Portland, OR?
+
French door installation in an existing rough opening typically runs $2,500–$6,000 for the door and installation, depending on the brand, glass package, and condition of the rough opening. Custom-sized or premium-brand French doors (Marvin, Andersen 400 Series) in larger sizes can run $6,000–$12,000+. Multi-panel folding systems are typically $15,000–$40,000+, depending on panel count and brand.
Do patio doors require a permit in Portland?
+
A like-for-like patio door replacement in an existing rough opening of the same size typically does not require a permit in Portland's jurisdiction. Any expansion of the rough opening — making it wider or taller — generally does require a permit as it involves structural modifications. Multi-panel folding door installations almost always require permits due to the structural header work involved. We assess permit requirements at the estimate stage and handle permitting on your behalf when required.
How long does it take to install a patio door?
+
A standard French door or sliding patio door replacement in an existing rough opening with no structural issues typically takes one full day. Multi-panel folding door installations typically take 2–3 days. Installations requiring structural rough opening modifications add time depending on the scope.
My existing patio door is leaking at the bottom. What causes that?
+
Threshold leaks on patio doors are almost always caused by a failed threshold seal, an improperly sloped threshold that allows water to pool against the interior, or a missing or failed sill pan below the door opening. The sill pan is a critical component that catches any water that passes the threshold and directs it to the exterior — without it, threshold leaks saturate the subfloor framing below the door.
Should I choose inswing or outswing French doors for Portland's climate?
+
Outswing French doors seal more effectively against wind-driven rain because the door closes against the stop rather than relying on compression weatherstripping alone. In Portland's wind and rain climate, outswing is often the preferred choice for exposed elevations — particularly for west-facing doors that take the brunt of Pacific storms.
My French door is drafty along the center meeting stile — is this fixable?
+
Yes, in most cases. Drafts at the center meeting stile are almost always a weatherstripping or astragal seal issue. The astragal is the vertical seal between the two door panels at the center. Weatherstripping replacement and astragal adjustment are repairs, not door replacements.
Can you replace my existing sliding patio door with French doors?
+
Yes — this is one of the more popular patio door upgrade projects. Replacing a sliding patio door with hinged French doors typically works within the existing rough opening if the opening is wide enough for two standard door panels. If structural changes are required, we assess feasibility and scope during the estimate visit.