Built Right.
Built Honest.
Family-owned general contractor & remodeler in St. Louis, MO
JonMas Construction is a family-run general contractor serving St. Louis and the surrounding area. We believe building relationships is just as important as building quality projects — every job is tailored to your vision, your budget, and your timeline.
Remodels, additions, and the small jobs other GCs won't take.
We take the time to understand your unique needs and deliver quality work that stands the test of time. Here's what we're hired for most.
Whole-Home Remodels
End-to-end renovations — design, demo, build, and finish. One crew, one timeline, one point of contact.
Kitchens & Baths
Cabinetry, tile, plumbing, fixtures. The rooms that sell a house, done with care for the rooms you live in.
Additions & Build-Outs
Mother-in-law suites, sunrooms, second stories, basement finishes. We handle permits and engineering.
Interior Finishes
Drywall, trim, paint, flooring. The detail work that makes a room feel finished, not just done.
Decks & Exteriors
Composite and wood decks, railings, siding, and exterior repairs that hold up to St. Louis weather.
Repairs & Punch Lists
Got a list of small things that have piled up? We knock them out in one or two visits — no minimum.
Tile & Flooring
Ceramic, porcelain, LVP, hardwood — new installs and replacements. We prep the subfloor and handle transitions.
Doors & Windows
Interior and exterior door installs, window replacements, and trim work. Proper flashing and weatherproofing included.
Accessibility Modifications
Grab bars, walk-in showers, wider doorways, ramp builds. Making homes safe and comfortable for every stage of life.
Real homes, real transformations.
Every project starts with a conversation about the space, the budget, and the timeline. Here's what those conversations turned into.
See the work in motion.
Quick clips from recent job sites. For the full reel, head over to our page.
A small selection from this year and last.
We work on a handful of projects at a time so each one gets real attention. Want to walk through one in person? We'll set it up.
Serving St. Louis and the inner-ring suburbs.
We stay close to home — usually within a 30-minute drive. That means quick site visits, faster response when something comes up, and a crew that knows the local code officials by name.
- St. Louis City
- Clayton
- Ladue
- Frontenac
- Creve Coeur
- Kirkwood
- Webster Groves
- Richmond Heights
- Brentwood
- Maplewood
- University City
Don't see your neighborhood? Give us a call — we travel for the right project.
A commitment to integrity and excellence.
The bar to call yourself a contractor is low. We hold ourselves to a higher one.
Real reviews from real homeowners.
Professional, easy to work with and delivered exactly what we wanted.
Exceptional experience. The professionalism, clear communication, and early project completion exceeded our expectations.
Completed on time and within budget with strong communication throughout the entire project.
Responsive, professional, and attentive to our needs and preferences. Couldn’t be happier with the results.
Things people ask before they call.
Got a project in mind? Let's talk it through.
Transparent quotes, flexible options that fit your budget, and no pushy sales pitch. We build lasting partnerships with our clients — built on trust and mutual respect.
Tell us about your project.
Fill out the form or give us a call. We typically reply within one business day.