Sunroom Additions
Three-season and four-season sunrooms built on a proper foundation, not a floating deck. Insulated glass, thermal framing, and real HVAC connections if you want year-round use.
Eau Claire, WI · Trusted Home Improvement Since 1993
Home Additions Built Right the First Time
Expand your home without moving. Midwest Home Improvements builds room additions, sunrooms, and more. 33 years of experience. Call for a free estimate.
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Midwest Home Improvements
Why Choose Midwest Home Improvements
A home addition is exactly what it sounds like: new living space added to your existing structure. That can mean a sunroom, a bedroom, a family room, a garage, or a full second story. Whatever the scope, the work has to tie into your existing foundation, framing, roofing, and electrical systems seamlessly or you'll be dealing with problems for years. We've been building additions across the region since 1993, and we know where the shortcuts are because we've seen other crews take them. Call (715) 894-1120 before you hire anyone else.
What drives the cost of a home addition is scope, not square footage alone. Foundation type, load-bearing wall modifications, roofline integration, finish level, and whether the space needs plumbing or HVAC all shift the number significantly. A modest bump-out might run $15,000 to $30,000. A full room addition with foundation, framing, insulation, windows, drywall, and finished flooring can run $50,000 to $150,000 or more depending on size and materials. We don't pad quotes with mystery line items, and we'll tell you straight up what the job actually involves before any work begins. Every job is different -- contact Midwest Home Improvements for an accurate estimate.
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What a Well-Built Addition Actually Involves
Most homeowners think of an addition as framing and drywall. The part nobody sees is what determines whether it lasts. The new structure has to share a roofline with the existing home, which means flashing, underlayment, and shingle matching done properly -- not just nailed down and hoped for. Exterior walls need to tie into the existing foundation or a new one, depending on span. Insulation values have to match or exceed the rest of the house or you'll feel it every January. We handle the full scope in-house. No hand-off to a separate framing crew, no surprises when the permit inspector shows up.
Types of Additions We Build
Every project starts with what the homeowner actually needs, not what's easiest to build.
Bedroom and Living Room Additions
Full structural additions that tie into existing framing and rooflines. Finished to match the rest of your home -- flooring, trim, paint, and electrical included in the scope.
Garage and Mudroom Additions
Attached garages and entry mudrooms that integrate with your home's exterior. We match siding, rooflines, and windows so the addition looks like it was always there.
Bump-Out Additions
Smaller footprint extensions that expand a kitchen, bathroom, or bedroom without a full addition. Good option when you need space but not a whole new room.
Second-Story Additions
The most complex category. Requires full structural engineering, load-bearing assessment, and careful coordination of roofline, staircase, and existing HVAC. We're honest about scope upfront.
What Separates a Good Addition from a Problem in Five Years
Here's what most contractors skip on additions: the thermal envelope. They frame the walls, blow in some batt insulation, and call it done. In Wisconsin winters, that's not enough. A properly built addition needs continuous air barrier, proper vapor management on the interior side, and insulated headers over windows and doors. We also match your existing siding on every exterior wall so the addition doesn't look like an afterthought from the street. If the roofline requires a valley, that valley gets ice-and-water shield, not just underlayment. The details that protect the structure aren't visible once the job is finished, which is exactly why they have to be done right the first time.
How Our Addition Projects Run
We start with a site visit, not a sales pitch. Stephen Bonander has been doing this for 33 years and he'll walk the property with you, look at the existing structure, and tell you what the job actually involves. From there we produce a written scope and estimate before any commitment. Permits are pulled before work starts -- not after the framing is up. Work runs on a defined schedule, and we don't leave a job half-done to go start another one. If you've had that experience with another contractor, you know how much it costs in the end. See some of our completed projects in our recent project gallery.
Key Facts About Home Additions
A few things worth knowing before you start planning.
Permits are not optional
Every structural addition requires a building permit. Any contractor who suggests skipping it is protecting themselves, not you.
Foundation type determines cost
A slab foundation costs less than a crawl space or full basement, but some sites or use cases require the latter. Get clear on this before you budget.
Matching materials takes planning
Siding, roofing, windows, and trim need to be sourced to match your existing home. This takes lead time -- it's not an afterthought.
Roofline integration is the hardest part
Where the new roof meets the old is where leaks happen if the flashing and underlayment aren't done correctly. Don't let anyone rush this step.
HVAC and electrical need real planning
A new room needs heat, cooling, and outlets. Adding those after framing costs more and looks worse. Plan them into the original scope.
Timeline is longer than most expect
A full room addition from permit to punch list typically takes 8 to 16 weeks depending on size, complexity, and material lead times.
Let's talk about your project
Honest advice and a clear estimate — no pressure, no obligation.
When a Full Addition Is the Right Call vs. a Remodel
A lot of homeowners come to us thinking they need an addition when a complete home remodel would solve the problem for less money. If the square footage exists and you're just not using it well, reconfiguring the existing layout is often faster and cheaper. Additions make sense when you've genuinely run out of floor plan -- you need a bedroom that doesn't exist, a garage the property doesn't have, or a space that can't be carved from what's already there. We'll tell you honestly which situation you're in. We won't push an addition if a remodel serves you better.
Reviews
What Our Customers Say
Honest work, on schedule, and no surprises.
Stephen walked the property with us before we signed anything and caught a drainage issue that would have caused problems with the new foundation. That kind of experience is exactly what you want on a project this size.
The addition looks like it was part of the original house. The siding, roofline, and windows all match. We've had guests who didn't realize it was an addition at all.
They pulled the permit before breaking ground, finished on the schedule they gave us, and the final cost matched the estimate. That's three things a lot of contractors can't manage. We'd hire them again.
Start Your Addition Project with a Real Conversation
Thirty-three years in this business means we've seen what goes wrong and how to avoid it. Call (715) 894-1120 to talk through your project and schedule a site visit.
Request a free estimate
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Good to Know
Frequently Asked Questions
What structural changes are required to add a room to an existing house?
At minimum, you're looking at a new foundation section or slab, exterior wall framing tied to the existing structure, and roofline integration. Load-bearing walls may need to be modified or reinforced. In Wisconsin, frost depth requires footings at least 48 inches below grade, which affects foundation cost. Electrical, HVAC, and insulation all need to connect to existing systems, and all of it requires a building permit before work starts.
How does a sunroom addition differ from a standard room addition?
A sunroom addition typically uses more glass and lighter framing than a standard room addition. A three-season sunroom isn't insulated to the same standard as the main house and isn't served by the main HVAC system. A four-season sunroom is fully insulated, uses thermally broken framing, and connects to your heating and cooling. The foundation requirements are the same either way. The choice between three-season and four-season depends on how you plan to use the space and your willingness to heat it year-round.
Does a home addition require a building permit in Wisconsin?
Yes. Any structural addition to a home in Wisconsin requires a building permit from the local municipality. This covers the foundation, framing, electrical, plumbing, and mechanical work. Unpermitted additions create real problems: they don't appear in the home's official square footage, they can void your homeowner's insurance for that space, and they become a liability when you sell. We pull permits before work starts on every project.
How long does it take to build a home addition from start to finish?
For a single-room addition of average size, plan on 8 to 16 weeks from permit approval to punch list. Permit approval alone can take 2 to 4 weeks depending on the municipality. Material lead times for windows, doors, and roofing products add time. Larger additions, second-story additions, or projects requiring significant structural engineering run longer. We give you a realistic schedule before work starts and we hold to it.
Will the addition match the exterior appearance of my existing home?
That's a goal we set on every project, not an afterthought. Matching siding profile, color, and texture requires sourcing materials that align with what's on your home. The same applies to roofing shingles, window styles, and exterior trim. Sometimes an exact match isn't possible if the original materials are discontinued. We'll show you the closest available options and be straight about what will and won't blend seamlessly before you commit.
Can a home addition include a deck or outdoor living space?
Yes. Many addition projects include an attached deck or railing system as part of the same scope. Coordinating the deck framing with the addition framing during the same build phase is more efficient and typically costs less than returning for a separate project. If the addition has a walk-out door to an outdoor space, planning the deck at the same time avoids a mismatched step height or an awkward landing situation.
What is a bump-out addition and when does it make sense?
A bump-out is a small structural extension, usually 2 to 10 feet, that expands an existing room without adding a full new room. Common uses include expanding a kitchen to fit an island, adding square footage to a bathroom for a larger shower or double vanity, or giving a bedroom enough space for a proper closet. A bump-out still requires a foundation and roofline connection, but the scope and cost are considerably less than a full addition.