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Home Addition in Ada — Fixed-Price Design-Build

Ada Township-experienced · Multi-room and full-second-story additions · Fixed-price contracts (the quote is the price) · 3D design sketch on the first visit · 2-year workmanship warranty · 4.7★ on Google

Master suite additions, second-story builds, bump-outs, sunrooms, garage conversions, in-law suites, ADUs, and full-wing expansions for Ada Village, Ada Township, the Thornapple River estates, and the Cascade/Forest Hills border. One team from permit to final walkthrough.

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4.7★ Google (19 reviews)
Licensed Michigan Builder #262300501
2-Year Workmanship Warranty
Fixed-Price Contract Guarantee
What an Ada-Tier Addition Actually Costs

Home Addition Costs: $100K to $200K+

Watch more addition walkthroughs on our YouTube channel

Where We Work From

Serving Ada & West Michigan

619 36th St SW, Wyoming, MI 49509 · About 25 minutes from most Ada addresses. By appointment only — we come to you for in-home consultations. · Open in Google Maps →

The Thornapple Difference

Why Ada Homeowners Pick Thornapple for Additions

Ada homes are not city Grand Rapids homes. The lots are larger, the finish expectations are higher, the permitting pathway is its own animal, and the projects routinely sit in the six-figure range. Four real things separate a Thornapple addition from the typical Ada-area remodeler.

Fixed-Price Certainty

The Quote Is the Price

An estimate is a guess. A fixed-price contract is binding. On a $200K, $400K, or $600K addition, that distinction is the single most important protection you have. The number we put in writing after design is the number you pay — no allowance games, no surprise change orders, no end-of-project reconciliation. The only way it moves is if you choose to change scope. See how the process works.

3D Design on the First Visit

You See It Before You Buy It

Our in-home Ada consultation is a working session, not a sales pitch. We measure your lot and existing structure, model the addition in real-time 3D in your living room, and hand back an honest budget range tied to actual scope choices — footprint, finish level, structural complexity — before you commit to anything. You walk away knowing what's buildable on your specific Ada lot and what it would cost.

Ada Township Permitting Handled

We Do Not Send You to the Township

Ada Township's permit pathway is unusual — permits route through Cascade Township, septic and well changes route through Kent County Health, and larger additions trigger site plan review. We handle every step end-to-end as part of the fixed-price contract. You never call a building department, never sit through a planning commission meeting, never chase an inspector for a sign-off.

Project Portal Access

You Always Know What's Happening

Every Thornapple client gets a private project portal with the full schedule, photo updates after each day on-site, change-order history, and a single point of contact. On a multi-month Ada addition that's the difference between living through chaos and living through a managed project. We expect to manage it so you don't have to.

Addition Types We Handle in Ada

Eight Kinds of Addition Project — One Process

A bump-out, a second story, and a full mother-in-law wing are very different jobs. The Thornapple process — discovery, design, fixed price, build, walkthrough — is the same for all of them. Ada lots are generally large enough that most of these options are on the table for your home.

Bump-Out Addition

Small footprint expansion — extending a kitchen, adding a breakfast nook, expanding a primary bath, or pushing a family room out a few feet. Often the most cost-effective way to fix the one thing that's been driving you crazy without rebuilding the whole house. Ada lots usually give us the setback room for this without a variance.

Sunroom & Four-Season Room Addition

Insulated, full-mechanical sunroom built to be used every month of the year — not a glorified screened porch. Tied into the main HVAC, with the windows and roof system designed for West Michigan winters. Common request on Thornapple River and wooded-lot properties where the view earns the investment.

Master / Primary Suite Addition

Ground-floor primary suite — bedroom, walk-in closet, spa bath, often a private sitting area or coffee bar. Built on grade for aging in place or to free up second-floor bedrooms for kids. The single most common addition type we build for Ada homeowners planning to stay in the home for the next 20 to 30 years.

Garage Conversion & Bonus Room

Converting an attached garage into living space — office, gym, guest suite, mudroom — usually paired with a new garage build on a different part of the lot. Common on Ada Township properties where the lot supports a detached garage and the original attached structure is the easiest place to add real living square footage.

In-Law Suite & ADU Addition

Multi-generational in-law suites and accessory dwelling units — full kitchen, private entrance, accessibility-ready design. We coordinate with Ada Township Planning and Zoning on what's permitted on your specific lot before design. Detail on our in-law suite additions and ADU builder pages.

Second-Story / Pop-Top Addition

Full second floor or partial second-story addition to a ranch or one-and-a-half-story home. Adds the most usable square footage without consuming yard space. Requires structural reinforcement of the existing first floor, careful coordination around an occupied house, and weather windowing on the exterior. We design that complexity in from day one.

Mudroom & Entry Addition

Often paired with a kitchen remodel or garage conversion — adding a real mudroom, pet station, drop-zone, and side entry to a house that was originally designed without one. Small footprint, outsized impact on day-to-day livability.

Full-Wing Multi-Room Addition

Major expansion — new wing with multiple rooms, in-law suite plus great room, dedicated home office and guest quarters, or full primary suite plus mudroom plus mechanical reroute. The "when you want the house to feel like a different house" scope. Custom architecture, full site plan review, highest level of finish.

How the Project Runs

Our Fixed-Price Design-Build Process

Five phases, no surprises. Every one is documented in your project portal so you always know where you are.

  1. Site Assessment & Discovery (2–3 hours, in-home, free). We measure your lot, existing structure, and the part of the house the addition will tie into. We listen to how you actually use the home and where it's failing you. We sketch options in real-time 3D and hand back an honest Ada-tier budget range. No commitment.
  2. Design. We refine the 3D model, finalize structural approach, finishes, fixtures, and how the addition integrates with the existing architecture. We pull every sub-trade into the same set of plans. You see everything — including how it'll look from the street — before anything is ordered.
  3. Fixed-Price Proposal. Itemized line by line. The number is binding once you sign. No allowance games. No "we'll figure it out later." On a $200K-plus addition this is the single biggest difference between a Thornapple project and most Ada-area builders.
  4. Build. Permits pulled through Ada Township and Cascade Township. Site plan review handled if required. Dust barriers installed at the addition tie-in so the rest of the house stays livable. Daily photo updates in your portal. Single point of contact. Foundation, framing, mechanical, electrical, plumbing, and final inspections scheduled and coordinated.
  5. Walkthrough & Warranty. We walk every detail with you before final payment, fix anything that isn't right, and back the workmanship for two years.

Want more detail on any phase? Read the full design-build remodeling process — or jump straight to booking a discovery call.

Real Ada-Tier Numbers

What a Home Addition Actually Costs in Ada

Below are honest 2026 ranges for Ada Township, Ada Village, the Thornapple River estates, and the Cascade/Forest Hills border. Pricing depends on scope, square footage, finish level, and structural complexity. Final pricing is locked into a fixed-price contract after the design phase. For the broader Grand Rapids-area breakdown, read our full home addition cost in Grand Rapids guide or run a quick estimate in the cost estimator.

Bump-Out Addition

$100,000 – $175,000

Small footprint expansion — kitchen extension, breakfast nook, primary bath bump, or family-room push. Usually the highest return per dollar spent on an Ada home where the layout almost works but one room is constraining everything.

Sunroom / Four-Season Room

$125,000 – $200,000

Insulated year-round sunroom with full mechanical integration. Built for the river view, the wooded lot, the morning light — without the seasonal limits of a screened porch.

Master / Primary Suite Addition

$175,000 – $325,000

Ground-floor primary suite — bedroom, walk-in closet, spa bath, often a private sitting area. Built on grade for aging in place or to redistribute family bedrooms. The most common Ada-area addition for homeowners planning the next 20 to 30 years.

Garage Conversion + Bonus Room

$125,000 – $200,000

Converting an attached garage into living space, usually paired with a new garage build elsewhere on the lot. Adds finished square footage without disturbing the rest of the floor plan.

Second-Story / Pop-Top

$275,000 – $475,000

Full second floor or partial second-story addition on a ranch or one-and-a-half-story home. Maximum usable square footage, no yard impact, longest timeline. Structural reinforcement and weather windowing are designed in from day one.

In-Law Suite / ADU

$200,000 – $400,000+

Multi-generational in-law suites and accessory dwelling units — full kitchen, private entrance, accessibility-ready. Ada Township ADU zoning rules dictate what's permitted on your specific lot — we confirm that in the discovery phase.

Full-Wing Multi-Room Addition

$375,000 – $650,000+

Major expansion with multiple rooms, in-law suite plus great room, full primary suite plus mudroom, or new wing with dedicated office and guest quarters. Custom architecture, site plan review, highest level of finish.

Per-Sq-Ft Benchmark

$450 – $650 / sq ft

The Ada-tier per-square-foot range depending on finish level, structural complexity, and addition type. Bump-outs at the lower end. Second-story and ADU at the upper end because of structural and mechanical complexity.

Ada properties on private wells or septic systems carry a meaningful adder when the addition increases bedroom count beyond the system's rated capacity or alters drain field setbacks. We plan for those realities in discovery and price them into the fixed contract — they don't become surprise change orders mid-build.

Ada Township Permits & Timeline

What's Different About Building in Ada Township

Ada Township's permitting pathway is its own animal. Permits and inspections are issued through Cascade Township — Ada contracts that work out. You submit the application and three sets of plans to Ada Township Planning and Zoning, the Zoning Administrator signs off on conformity with Ada's zoning standards, water and sewer connection fees are paid where applicable, and then the application moves to Cascade Township for issuance and inspection.

Larger additions — anything changing the building footprint, impacting drainage, or coming close to setback or lot-coverage limits — trigger site plan review before permits issue. That adds roughly 4 to 8 weeks to the pre-construction timeline. Additions on PUD-zoned lots have their own special setback rules. Additions affecting well or septic systems trigger a Change of Use review and require permits from the Kent County Health Department in addition to the township permit.

Thornapple handles every step of that pathway as part of the fixed-price contract — the Ada Planning and Zoning submittal, the Cascade Township coordination, the Kent County Health filing where it applies, every inspection, every condition that comes back from site plan review. You don't step into a township office. Read more on our Grand Rapids remodeling permits page.

Multi-room home addition in Ada, MI by Thornapple Construction — exterior integrated with the original home
Recent Projects

Three Recent Thornapple Home Additions

Real Thornapple addition projects from Ada and surrounding West Michigan homes. Descriptive names — no client names, no street addresses. See the design intent, the integration with the existing structure, and the protection process at work.

Plymouth Wing Addition — multi-room rear addition with seamless exterior integration in a West Michigan home by Thornapple Construction
Ada-Area · Multi-Room Wing Addition

Plymouth Wing Addition

A multi-room rear addition expanding the kitchen footprint and adding a full great room, with the exterior trim, roofline, and siding matched precisely to the original house so the addition reads as if it had always been there. Scope: structural tie-in, full mechanical extension, kitchen rebuild, great room, exterior integration, and landscape restoration.

See the Project →

Sunroom Year-Round Addition — insulated four-season sunroom with full mechanical integration in a West Michigan home by Thornapple Construction
West Michigan · Four-Season Sunroom

Sunroom Year-Round Addition

An insulated four-season sunroom addition built to be used every month of the year, not just summer. Scope: full HVAC tie-in to the main house, engineered window package for West Michigan winters, properly sized header and structural support, finished interior with trim level matching the rest of the home, and exterior siding and roofline carried over so the room reads as original.

See the Project →

Rear Footprint Expansion — kitchen and family-room rear addition with exterior trim matched to the original home, built by Thornapple Construction
West Michigan · Rear Footprint Expansion

Rear Footprint Expansion

A rear footprint addition adding meaningful kitchen and family-room square footage, with exterior trim, siding profile, and roof pitch matched to the original house so the addition disappears into the architecture. Scope: foundation, framing, structural tie-in, kitchen extension, full exterior integration, new windows matching the existing pattern, and landscape restoration along the rear elevation.

See the Project →

See All Thornapple Projects →

What Our Clients Say

In Their Own Words

“Nate and Austin are great to work with, can pivot throughout the project and address obstacles that sometimes arise. Communication was constant and the result was exactly what we asked for.”

M
Michelle S.
Whole-Home Remodel

“More than accommodating, professional, personable, and kept me updated every step of the way. Communication and work completed was high quality.”

A
Ashley G.
Bathroom Remodel

“Incredible! Reliable, friendly, hardworking, passionate about their work. Highly recommended.”

D
Debi A.
Home Remodel
Home Additions Near Ada

Neighborhoods Near Ada We Also Serve

Ada doesn't exist in isolation. Forest Hills schools, the Cascade Township border, the East Grand Rapids corridor, and the broader Kent County remodeling market all touch the same houses and the same homeowners. From our Wyoming office about 25 minutes from most Ada addresses, we cover the full surrounding service area.

  • Forest Hills — bathroom remodels and aging-in-place builds across Forest Hills Northern, Eastern, and Central. Permit jurisdiction varies by sub-neighborhood (Grand Rapids Township vs Cascade Township) — we handle the coordination.
  • East Grand Rapids — Gaslight Village and Reeds Lake homes. Kitchen and primary suite work that requires historic detail with modern systems.
  • Cascade Township — the township that issues Ada's building permits. Full-suite primary baths, basement bathroom builds, and home additions across Cascade. Basement finishing in Cascade often pairs with addition work.
  • Kentwood — home additions, kitchen remodels, and full-home renovations across Kentwood neighborhoods.
  • All Ada Services — kitchen remodels, bathrooms, basements, and whole-home renovations for Ada homeowners. The full Ada service page.
  • Grand Rapids — Heritage Hill, Eastown, Creston, Alger Heights, Garfield Park, Ottawa Hills, East Hills, Cherry Hill. Older homes with their own structural realities.
  • See all service areas →
The Long-Term Ada Home

An Addition Designed for the Next Thirty Years

A meaningful share of Ada home additions are not for the next five years — they're for the next thirty. The Forest Hills school district, the Thornapple River view, the wooded lot, the neighbors you've known a decade — none of that needs to change. The floor plan does. And the goal isn't to outgrow the home, it's to make it work for the rest of your life.

We design for that future intentionally. Ground-floor primary suites that disappear into the architecture but solve the upstairs-bedroom problem before it becomes a problem. In-law suites with separate entries for an aging parent who needs proximity and privacy. ADU additions for an adult child returning home, a remote-working family member, or eventual short-term-rental optionality if Ada Township allows it on your lot. Wider doorways, comfort-height fixtures, reinforced wall blocking for grab bars where they'll eventually go — designed in, never bolted on later.

Done right, you won't see the planning. You'll see an Ada home that simply feels good — at fifty, at seventy, at every stage in between. The aging-in-place framework is detailed on our accessibility remodeling in Grand Rapids page. Multi-generational and in-law suite specifics live on our in-law suite additions page.

Long-term home addition designed for aging in place in Ada, MI by Thornapple Construction
Common Questions From Ada Homeowners

Answers Before You Even Have to Ask

The real questions Ada homeowners ask before committing to a six-figure addition — not the generic ones the other guys recycle.

Ada home additions typically run from $100,000 for a small bump-out up to $650,000+ for a full-wing or large second-story addition. The bands we see most often: bump-out and small footprint additions $100K–$175K; sunroom and four-season rooms $125K–$200K; ground-floor master suite additions $175K–$325K; garage conversions $125K–$200K; second-story additions $275K–$475K; in-law suites and ADUs $200K–$400K+; full-wing multi-room additions $375K–$650K+. The Ada-tier per-square-foot benchmark lands in the $450–$650 range depending on finish level. Every Thornapple project locks at a fixed-price contract once scope is finalized — the price we quote is the price you pay. Full breakdown in our home addition cost guide.

Yes. Ada Township requires a building permit for virtually every home addition. The pathway is unusual: Ada Township contracts with Cascade Township for permit issuance and inspections. You submit the permit application plus three sets of plans to the Ada Township Planning and Zoning Department. After Ada's Zoning Administrator signs off on conformity with zoning standards and any required water and sewer connection fees are paid, the application moves to Cascade Township for issuance. Larger additions, footprint changes, drainage impacts, or proximity to setback or lot-coverage limits often trigger site plan review before permits issue. Thornapple handles the entire pathway end-to-end so you never have to coordinate with either township. Full detail on our remodeling permits page.

Most Ada home additions run 5 to 10 months from permit issuance to final walkthrough. Bump-outs and sunrooms typically land at 3 to 4 months. Master suite additions usually run 5 to 6 months. Second-story and full-wing additions run 7 to 10 months depending on scope, structural reinforcement, finish level, and weather windows on exterior trades. Design and permitting add roughly 8 to 14 weeks before construction begins — longer if site plan review is required by Ada Township. Every milestone is mapped in your fixed-price contract and tracked in your project portal before the first piece of demolition.

Ada lots are generally larger than Grand Rapids city lots, so ground-floor master suite additions are more feasible here than they are inside the city — you usually have the yard space and the setback room. Ground-floor master suites are faster, cheaper, and friendlier to aging in place. Second-story additions preserve your yard and add the most usable square footage, but they require structural reinforcement of the existing first floor and a longer build timeline. We model both options in 3D during the design phase so you can see the trade-offs — yard impact, light, traffic flow, cost — before committing to either.

Yes. In-law suite and ADU additions are an increasingly common request in Ada — usually multi-generational families wanting an aging parent close but with privacy, or families building a separate suite for an adult child or guest quarters. Ada Township allows accessory dwelling units under specific zoning conditions, with rules around size, setback, separate entrance, and occupancy. We coordinate with Ada Township's Planning and Zoning Department to confirm what's permitted on your specific lot before we design the addition. Detail on our ADU builder and in-law suite additions pages.

Many Ada properties — particularly larger lots along the Thornapple River and in less-dense Ada Township sub-areas — are on private wells, septic systems, or both. Additions that may affect well or septic systems trigger a Change of Use or Addition review and require permits from the Kent County Health Department in addition to the Ada Township building permit. That can include drain field setback verification, well location confirmation, or in some cases a septic upgrade if the addition increases bedroom count beyond the system's rated capacity. We map this out during the discovery phase so it's priced into the fixed contract and scheduled into the timeline — not discovered mid-build.

The Ada-tier benchmark lands in the $450 to $650 per square foot range, depending on finish level and structural complexity. Bump-outs at the lower end of that range. Second-story additions toward the upper end because of structural reinforcement, weather exposure during construction, and the need to coordinate around an occupied first floor. ADU and in-law suites with full kitchens, separate entries, and accessibility features can push past $650 per square foot. For comparison, a basic addition in lower-cost West Michigan markets can land in the $300–$400 range — Ada's higher number reflects finish expectations, site logistics, and the Ada Township permitting pathway.

For most Ada homeowners, yes. Between tight Ada and Forest Hills inventory, Forest Hills Public Schools district demand, real-estate commissions on a sell-plus-buy, transfer taxes, moving costs, and the premium you'd pay for someone else's compromised floor plan, a well-designed addition almost always pencils out better than a move. You keep the lot, the river or wooded view, the neighbors, the school district, and the address — and you finally get the floor plan you actually want. We run the real numbers honestly during the discovery call so you can make the call with full data, not a guess.

An estimate is a guess that can move. A fixed-price contract is a binding number after the design and scope are finalized — the price we quote is the price you pay. No allowance games, no surprise change orders, no end-of-project reconciliation. The only way the price changes is if you choose to change the scope, and that change is itemized, priced, and approved before any work happens. On a six-figure Ada addition project, that protection is the single biggest difference between Thornapple and the typical Grand Rapids remodeler.

4.7★ Google (19 reviews)
Licensed MI Builder #262300501
2-Year Workmanship Warranty
Fixed-Price Contract Guarantee

Ready to Plan Your Ada Home Addition?

It starts with a free discovery call — a quick conversation to talk through your project, get honest answers, and see if we're the right fit. No commitment. No pressure. Just clarity.

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