Expert Home Additions Services
An addition is really a small house attached to the one you already have, and the seam between them is where most projects go wrong. We run the whole thing as one job with one schedule, so nobody's pointing at the next trade. The engineering and the village approvals are done before we break ground, one of us is here while it goes up, and you can check the schedule, any change orders and your balance in your portal whenever you want.
- Typical range
- $200–$400 per sq ft
- Typical project
- $60,000–$120,000 for ~300 sq ft
- Permits
- Zoning review, plans and permits handled
Ranges are typical for our Chicagoland projects — see full cost breakdowns. Your itemized estimate is free.
What We Offer
Zoning & feasibility
Setbacks, lot coverage and height limits checked with your village before design time is spent on something that cannot be built.
Foundation & framing
Footings and foundation sized for local frost depth, framed and tied into the existing structure by engineered detail.
Roof & envelope tie-in
The join done properly — flashing, water management and insulation continuity, so the new roof does not leak into the old one.
Second stories & dormers
Including the structural work to carry a new floor on a house that was never designed for it.
Mechanical capacity
Honest assessment of whether existing HVAC, electrical service and water heating can carry the added square footage.
Exterior matching
Siding, roofing, brick and trim matched so the addition reads as part of the house rather than bolted on.
Our Process
ProcessThe same six stages on every job — free in-home estimate through warranty.
Free in-home estimate
Greg or Patryk — the owners, not a salesperson — walk your space, take real measurements, and give you honest feedback on what your budget buys.
Itemized scope & contract
Labor, materials, demolition and disposal priced line by line, not one mystery number. Payment terms and warranty are in the written contract.
Design & selections
Bring your own designer, use our architects and designers, or choose everything yourself. Selections are scheduled ahead so lead times never stall the site.
Permits & scheduling
We pull and manage building, plumbing and electrical permits with your village — typically 1–2 weeks — and hand you a written schedule before demo day.
The build, owner-supervised
Long-standing trade partners working in sequence under daily owner supervision. Your client portal shows the schedule, change orders and current balance.
Walkthrough & warranty
We walk the finished job together, close out every punch-list item, hand over manufacturer paperwork, and your written workmanship warranty starts. Our commitment never expires.
What’s Included
Labor & installation we include
- Structural engineering coordination and permit drawings
- Excavation, foundation and framing
- Roofing, siding and exterior finish matched to the existing home
- Electrical, plumbing and HVAC extension
- Insulation, drywall, flooring and finish carpentry
- Final walkthrough, punch list and warranty paperwork
You supply / quoted separately
- Finish materials — flooring, tile, cabinetry, plumbing and lighting fixtures, windows, doors and hardware
- Architectural design fees, when you engage your own architect
- Utility service upgrades required by the village
You choose and purchase the finish materials; we specify what is needed, schedule it against the build, and install it. Listed openly so nothing on your final invoice is a surprise.
Testimonials
Your Neighbours Love Us
Real reviews from homeowners. Ask us for live phone references.
I cannot say enough good things about Greg & Patryk and their team! One of my biggest hesitations about doing such a large project was knowing how hard it is to find a reliable contractor who would give us top quality work at a reasonable price. GS Construction exceeded our expectations in all areas! Our first floor remodel (kitchen renovation with wall removal, half bath remodel, new hardwood floors, updated laundry room) was completed right on schedule. Their attention to detail is amazing, often fixing or adjusting things that I didn't even notice. Their team was a pleasure to have in the house, all were so respectful and patient with our family as we mostly worked from home through the construction. The quality of work from their entire team (carpenters, plumbers, hvac, and painters) was well worth the price. We are beyond thrilled with our updated house! I would recommend GS in a heartbeat and will definitely call on them when it is time to update the rest of the house.
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Ready to Add Space to Your Home?
Get a free consultation and quote for your remodeling project. GS Construction is ready to bring your vision to life.