Home additions in the Lehigh Valley range from about $80,000 for a small bump-out to $650,000 or more for a two-story addition. Most fall between $250 and $450 per square foot of new space. Foundation work, plumbing and how the new space ties into the existing house drive most of the difference. Below are the ranges we use when planning additions in Easton, Forks Township and nearby towns.
Why Lehigh Valley additions vary in cost
An addition is new construction attached to an existing house, and the existing house sets many of the constraints. Lot size and setbacks determine where an addition can go. The age and condition of the home determine how much work it takes to connect new framing, roofing, heating and electrical to what is already there. Adding a bathroom or kitchen brings plumbing into the scope, which is the largest single jump in cost.
Not sure where your project falls?
We walk every property before putting a number on an addition. A site visit is the fastest way to get a range that actually reflects your home and lot.
Bump-out, single story or two story
A bump-out extends an existing room by a few feet, usually without a full foundation. It is the most efficient way to add space to a kitchen or primary bathroom. A single story addition adds a new room on its own foundation with a new roof. A two-story addition stacks space vertically, which costs more overall but often less per square foot, because the foundation and roof serve two floors.
What older Lehigh Valley homes add to the scope
Additions to older Easton homes need careful planning where new construction meets old. We plan for:
- Matching rooflines, siding and window proportions so the addition looks original to the house
- Tying modern framing into older structures that are rarely square or level
- Electrical service and heating systems that may not have capacity for new space
- Tight city lots, where setbacks and neighboring homes limit where an addition can go
- Historic review for exterior changes to homes in Easton's historic districts, in addition to the building permit
In Williams Township and other areas on septic systems, adding a bedroom can also require confirming the septic system has capacity.
Home addition cost by type
| Addition type | What it includes | Typical range |
|---|---|---|
| Bump-out | 100 to 200 square feet extending an existing room, no new full foundation | $80,000 to $150,000 |
| Single story room addition | New foundation, framing, roof and full integration with the house | $150,000 to $300,000 |
| Addition with bathroom or kitchen | Single story addition with new plumbing | $250,000 to $450,000 |
| Two-story addition | Two finished floors on a new foundation | $350,000 to $650,000 and up |
These are planning benchmarks, not quotes. Most additions fall between $250 and $450 per square foot. We recommend a contingency of 10 to 15 percent.
How this compares to Bucks County
Addition costs in the Lehigh Valley are comparable to Bucks County and Montgomery County. Permitting timelines differ more than construction costs, since each municipality runs its own review. For comparison, see our Bucks County home addition cost guide. If you are weighing an addition against reworking the space you already have, our whole home renovation page walks through that decision.
Ready to talk through your Lehigh Valley addition?
We work throughout Easton, Forks Township and the surrounding area. Download our remodeling cost guide or get in touch to talk through your project specifically.
Frequently asked questions
How much does a home addition cost per square foot in the Lehigh Valley?
Most additions run $250 to $450 per square foot of new space. Bump-outs and simple single story additions sit at the lower end. Additions with bathrooms, kitchens or complex rooflines sit at the higher end.
Do I need a permit for a home addition in the Lehigh Valley?
Yes. Every addition requires a building permit, and many also need zoning review for setbacks and lot coverage. Exterior changes to homes in Easton's historic districts typically require historic review as well. We manage the permitting process from start to finish.
How long does a home addition take?
Design and permitting usually take two to four months. Construction typically takes three to six months depending on size and complexity, with two-story additions and additions with kitchens at the longer end.
Do you build additions outside Easton and Forks Township?
Yes. We also work in Palmer Township, Williams Township and other nearby Lehigh Valley towns. Call us to confirm your address is within our service area.
Is an addition or a renovation the better choice?
An addition makes sense when your home's footprint cannot meet your needs. A renovation is often the better investment when the space exists but does not work well. We help you compare both before any design work begins.
Planning a home addition in the Lehigh Valley?
Download our remodeling cost guide for realistic ranges across all project types, or get in touch to talk through your addition specifically.
