Home Additions in Bryn Mawr, PA
Bryn Mawr homes were built to a standard, and an addition has to meet it. We design and build custom additions that match the stone, proportions and detail of Main Line architecture — and are engineered properly behind the walls.
What a Home Addition Costs in Bryn Mawr
Main Line additions generally run $250–$400 per square foot all-in, and matching older stone, stucco or slate pushes toward the upper end. A single room addition of 200–300 sq ft typically lands at $60,000–$130,000; a rear kitchen and family room extension $150,000–$300,000; and a second story $200,000–$450,000+.
On Bryn Mawr’s century-old homes a meaningful share of that budget is structural and invisible — footings, beams and service upgrades — before a single finish is chosen. We price it honestly up front.
Size-by-size figures are in our home addition cost guide.
Types of Room Additions We Build in Bryn Mawr
Rear & Side Room Additions
Opening the back of the house for a larger kitchen and family room — the most common request, and the one that changes daily life most.
Second Story Additions
Bedrooms and baths over an existing wing or garage, keeping the footprint and grounds intact. See second story addition costs.
In-Law Suite Additions
A private suite for a parent or returning adult child. See our in-law suite cost guide and in-law suites in Villanova.
Primary Suite Additions
A modern owner’s suite with a spa bath and dressing room, added where the original plan has small, equally sized bedrooms.
Custom Additions That Match Bryn Mawr’s Historic Homes
Bryn Mawr has some of the best housing stock on the Main Line: stone colonials, Tudors and center-hall homes on generous lots, many of them a century old. There is usually room to build, but anything added has to hold its own next to the original — stone coursing, mortar colour, slate, window proportion and roof pitch.
Those are the details that decide whether an addition looks original or obvious. They take longer and cost more, and they are the reason a cheap bid on a Bryn Mawr addition is usually a warning.
It is also old construction. Behind the plaster there is often balloon framing, original wiring, undersized footings and rooflines that were never meant to be tied into. As a design-build addition contractor we handle design, structural engineering, permitting and construction under one roof, so all of it is found and priced before you sign.
How a Bryn Mawr Home Addition Works, Step by Step
Consultation
We walk the property, look at what is really there structurally, and talk honestly about scope and budget.
Design & engineering
Architecture that matches the original house, with structural calculations and a fixed scope behind it.
Permits
Bryn Mawr spans Lower Merion, Radnor and Haverford townships. We prepare the package and manage review through approval.
Build
One crew, one schedule, one point of accountability — through final inspection and walkthrough.
Home Addition Builders Near Bryn Mawr
We build additions throughout the Main Line — home additions in Ardmore covers the same work on the tighter lots a mile east, and we regularly build in Haverford, Gladwyne, Rosemont and Newtown Square. Remodeling inside as well? See kitchen remodeling and basement remodeling in Bryn Mawr.
Bryn Mawr Home Addition FAQ
What does a home addition cost in Bryn Mawr?
Main Line additions generally run $250–$400 per square foot all-in. A 200–300 sq ft room addition typically costs $60,000–$130,000, a rear kitchen and family room extension $150,000–$300,000, and a second story $200,000–$450,000+.
Do you build custom additions or work from plans?
Every addition we build is custom. We design it to the house and lot, engineer it, and build it — or build from your architect’s drawings if you already have them.
Can you match the original stone and slate?
Yes, and it is a large part of what we do here. Matching stone, mortar colour, joint profile, slate and window proportions is what makes an addition read as part of the original house.
Are older Bryn Mawr homes harder to add to?
Generally yes. Century-old homes often need footing work, new beams, electrical service upgrades and careful tie-in to existing rooflines. It just needs to be found and priced during design rather than mid-build.
How long will a Bryn Mawr addition take?
Typically three to five months of design, engineering and approvals, then four to eight months of construction. Slate, custom windows and historic detailing can extend that.
Will the addition add value?
On the Main Line, additions that add functional space — a proper kitchen and family room, an owner’s suite, an in-law suite — are among the strongest-returning improvements, provided the work matches the quality of the original house.