Custom Four-Season Sunrooms & Room Additions in Madison, WI

Make Your Favorite View Part of Your Everyday Space

There’s usually a spot in the house that feels like it has more potential. Maybe it’s a sliding door that looks out to the yard or a corner that gets great natural light for a few months out of the year. Then winter hits, and that space goes unused.

A four-season sunroom changes that. Instead of closing things off for half the year, you get a space you can actually use year-round. Frey Construction has been building sunrooms and room additions across South Central Wisconsin since 1995, helping homeowners turn overlooked areas into functional living spaces.

Built for Wisconsin Winters

A sunroom that’s not designed for cold weather can quickly become unusable. Drafts, cold floors, and condensation are all signs that the space is not properly built for the climate. We design four-season rooms with insulation levels and materials suited for South Central Wisconsin.

Energy-efficient glass helps reduce heat loss while still bringing in natural light, and each addition is designed to work with your home’s existing heating system without overloading it. Getting these details right from the start is what separates a comfortable, usable space from one that only works a few months out of the year.

Three-Season Porch Vs. Four-Season Sunroom Options

Not all sunrooms are built for the same purpose, and in Wisconsin, that difference matters. Most homeowners are deciding between a three-season porch and a four-season sunroom, depending on how they want to use the space and what level of investment makes sense for their home.

Three-Season Porch: Designed for spring, summer, and fall. It’s a great choice if you want a more outdoor feel and added living space during the warmer months without the cost of full heating and cooling.
Four-Season Sunroom: Built for year-round use. That means insulated framing, energy-efficient windows, proper air sealing, and connection to your home’s heating system so the room stays comfortable even through Wisconsin winters.

Whichever option you choose, the home addition should look and feel like a natural part of your home. We design both three-season and four-season spaces to match your existing rooflines, siding, and overall style. The four-season porch addition in Spring Green and the four-season room addition in Lodi show the range of what's possible.

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Featured Customer Review

We recently had our home remodeled by the team at Frey Construction. The entire Frey team was professional, experienced, courteous and patient. The final result was exactly how we had envisioned. If we have other home remodeling projects in the future, we would certainly not hesitate to call Frey Construction again.

Joe H.

What to Expect From the Design-Build Process

We manage the entire process, so you don’t have to coordinate multiple companies.

Free Design Consultation

We start with a conversation about your goals, your space, and what’s realistic for your home. If you move forward, we create detailed plans, renderings, and accurate pricing so you know exactly what to expect.

Construction with Oversight

A Frey project manager is on-site throughout construction, coordinating work and making sure everything stays on track.

Final Walkthrough

Before we wrap up, we walk through the finished space with you to confirm everything meets your expectations.

Why Madison Homeowners Choose Frey Construction

We’ve been building additions since 1995, and a large portion of our work comes from repeat customers and referrals. That speaks to the experience homeowners have working with us and the quality of the finished product.

Our team has also been recognized as a multiple-year “Best of Madison” winner, and we back every project with a 15-year workmanship warranty. For a four-season room, long-term support matters because performance shows up over time, especially through Wisconsin winters. Read what people say about working with us to hear directly from people who've been through the process.

Sunroom Additions Across South Central Wisconsin

We build sunrooms and room additions throughout the Madison area and surrounding communities, including Middleton, Waunakee, Verona, Fitchburg, Sun Prairie, DeForest, Sauk City, Prairie du Sac, Cross Plains, Lodi, Baraboo, and Black Earth.

If you are in or near these areas, we can come out to evaluate your space and talk through your options. For complete coverage details, visit our full service area page.

Common Questions About Four-Season Sunrooms

Sometimes. Smaller rooms can often connect to your existing system or use supplemental heating, while larger additions may require expanded capacity. We review this during the design phase.

Sunrooms use more glass to bring in natural light, while standard additions follow more traditional wall and window layouts. Four-season sunrooms are designed to balance that natural light with insulation and energy efficiency.

Yes. We manage the design, permitting, and coordination so you do not have to handle those details yourself.

When built correctly, yes. A properly insulated and heated four-season room stays comfortable even during the coldest months.

Start Your Sunroom Addition With a Free Consultation

If you’ve been thinking about adding a sunroom, the best place to start is a simple conversation. Reach out to schedule your free design consultation and take the first step toward a space you can enjoy all year.

Customer Stories

Don't just take our word for it...

Joe H.

I am very pleased with Frey Construction. They replaced my roof and gutters. The workers were fast and efficient, and they were always courteous and professional. The office staff was patient and helpful and I appreciated all the time they spent to answer my questions. The quality of work is exceptional and they exceeded my expectations with the clean up afterwards. I highly recommend them!

Brenda A.

Frey has done a lot of work for us and the quality is always great. My favorite thing about them is that they are extremely responsive and professional with great customer service. We've previously worked with them on siding and gutters. Most recently I had some windows replaced. They were very helpful and assisted in removing a wall-mounted shelf, which I consider an above and beyond service.

Sarah M.