Tigard Home Additions

Where new meets old is where an addition is judged

The success of an addition is measured at the seams — the roofline, the siding, the floor level, and the foundation where new meets old. JDI Construction is a family-owned, Vancouver-based design-build remodeler, and on an addition our work is really two jobs at once: building the new space, and marrying it to the existing foundation, roofline, and walls. Tigard's established suburban neighborhoods off Highway 99W are full of homes with good bones and settled lots — exactly the kind of house where a well-planned addition can add real living space without touching the character of the street. And an addition is not an ADU: it expands the home you already have, sharing its roof, systems, and foundation, rather than standing alone as a separate unit.

Our designers and trades work as one team, so the addition you approve is drawn to tie into the house that's actually there — we don't hand a set of plans to a separate crew and hope the new roof and foundation line up. Here's how additions get built, the decisions that come first, and what shapes cost and timeline.

The four seams that make or break it

An addition looks original or looks bolted on depending on four seams where the new work meets the existing house. These are where we concentrate the effort:

1. 1
   

   FoundationConnecting new footings to the old foundation so the addition doesn't settle differently.
2. 2
   

   Roofline & pitchMatching pitch and tying the new roof in so it sheds water and looks original.
3. 3
   

   Exterior skinMatching siding, trim, and color — hardest on older homes where materials have aged.
4. 4
   

   Interior transitionsFloor heights, ceiling lines, and finishes that flow instead of announcing a seam.

A few decisions worth making early

An addition rests on a few decisions that come before design. The first is up or out: building out is usually simpler and cheaper when the lot has room, which many of Tigard's established suburban lots do, while going up a second story preserves the yard but means confirming the existing foundation and framing can carry the extra load. The second is capacity — whether the current foundation, electrical panel, and heating and cooling system can serve the added square footage or need upgrading as part of the work. The third is what the parcel allows: setbacks, lot-coverage limits, and height rules that vary by jurisdiction, and often by neighborhood HOA. We work through all of it up front so the plan fits the house, the lot, and the budget.

What Tigard homeowners add on for

Most additions we build in Tigard come from wanting more of a home and a neighborhood that already work: a primary suite, another bedroom or two, a larger family room, or a dedicated home office. Because an addition is attached and shares the roof, systems, and foundation with the main house, it keeps everything under one roofline instead of becoming a separate structure the way an ADU would — usually the more practical route on an established suburban lot.

The matching challenge depends on when the home was built. The older established homes closer to 99W ask for siding, trim, and roof profiles that have aged over the years to be matched carefully. The newer subdivisions are easier to match on materials but more likely to carry HOA and lot-coverage rules that shape where and how you can expand. Either way, we treat the seams — foundation, roofline, exterior skin, and interior transitions — as the part that decides whether the addition looks original or added on.

What does a home addition cost in Tigard?

Addition cost is driven first by type: a bump-out that borrows from the existing structure is far less than a second-story addition that requires reinforcing the foundation and framing below it. After that it's size, how much structural work the tie-in requires, how hard the existing materials are to match, and whether the systems need extending or upgrading. Because our design and our trades are both in-house, we can price the structural realities honestly up front and give you an itemized estimate once the addition is drawn, so the number reflects your house and your lot rather than a generic per-square-foot figure.

How long does a home addition take?

An addition is a months-long project more than a weeks-long one, because it runs through design and engineering, permitting, foundation and framing, tying into the existing structure, and then finishes. Second-story and structural additions take longer than a simple bump-out. We give you a realistic schedule before demolition, handle the engineering and permits the work requires, and sequence it to keep the existing home weather-tight and livable while the new space goes up.

Why homeowners in Tigard choose JDI

An addition is where design-build earns its keep, because the design, the structural engineering, and the construction all have to agree for new and old to meet cleanly. As a single accountable team, we handle the plans, the load paths, the tie-in, and the finishes under one roof, so nothing falls through the gap between an architect and a separate builder. We manage the permitting, keep you updated through our client portal, and stand behind the work with a five-year workmanship warranty. JDI is just across the river in Vancouver, a short drive from Tigard, so we're close enough to be on-site and responsive throughout a project this involved.

JDI Construction — "Built by family. Trusted by neighbors." Design-build remodeling and home additions based in downtown Vancouver, WA, serving Tigard and the greater Portland–Vancouver metro since 2007.