Additions · Kitchen extensions
Home additions & kitchen extensions in Boulder County
RSRT Construction builds home additions, room additions and kitchen extensions in Boulder County, Broomfield and nearby towns. The owners, Alex and Sergei, walk the site with you, put the price in a written line-item estimate and stay on the job.
- Licensed & insured
- 2-year workmanship warranty
- Written line-item estimate
- Owners on the job
What we build
More room for your house
An addition gives you floor area the house doesn't have today. Here is what we build and how the new space joins the rest of the house.
Room additions
A new room built onto the house, such as a bedroom, a family room, an office or a bigger primary suite. It gets its own foundation and ties into your roof, walls and heating.
Kitchen extensions & bump-outs
More floor space for the kitchen, built out past an outside wall. That makes room for a larger island, more counters or a place to eat. A bump-out is a small build-out on one wall.
Opening old into new
The wall between the house and the new space comes out or gets a wide opening, often with a beam. Floors, ceilings and trim are matched so the new room feels like part of the house.
What an addition involves
From plans to finished room
An addition is a small building project attached to your home. We run the build, and you talk with the owners the whole way. Alex and Sergei do the framing, plumbing and electrical themselves and hold Colorado plumbing and electrical licenses. The foundation and the roofing go to concrete and roofing crews we work with regularly.
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Walkthrough
We look at the house and the spot where you want to build, and talk through what the new space needs to do.
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Plans & engineering
An addition needs drawings for the permit. When the job requires it, a qualified engineer designs the foundation and framing. Tell us what plans you already have. At the walkthrough we explain what the job still needs.
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Permits & inspections
The plans go to your city or county for a building permit. We handle permits and coordinate inspections where required, as each stage of the build is ready.
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Foundation
Digging, footings and the foundation for the new space, built to the approved plans.
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Framing & roof tie-in
Floor, walls and roof framing, then tying the new roof into the old one so it sheds water and looks like it belongs.
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Windows, siding & roofing
Windows, doors, siding, trim and roofing, matched to the house as closely as the materials allow.
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Heating, electrical & plumbing
Heat and cooling for the new room, new circuits and lighting, and plumbing if it holds a kitchen or bath.
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Opening up & finish
Insulation, drywall, flooring, trim and paint, and the opening from the old rooms into the new one.
Build out or rework?
An addition, or a better use of the space you have
An addition is the right call when you need more floor area: another bedroom, a bigger kitchen than the house can hold, or a room that doesn't exist yet. It is also the largest of these options, because it needs a foundation, a roof and outside work.
Before building out, it is worth checking whether the rooms you already have can do more:
- Take out a wall. Opening the kitchen to the dining or living room can make a small kitchen feel much bigger. If the wall carries load, a beam replaces it. See load-bearing wall removal.
- Remodel the kitchen in place. A new layout, an island and better storage can fix a kitchen that doesn't work. See kitchen remodeling.
- Finish the basement. If you need a bedroom, an office or a family room, an unfinished basement may give you the space without building out. See basement finishing.
Some homes need both: an addition plus changes to the rooms around it. For work across several rooms, see whole-home remodeling. At the walkthrough we look at the options with you.
Before you add on
Sometimes a bigger kitchen fits inside the house
Not every bigger kitchen needs an addition. In this Superior home we made the kitchen bigger inside the existing walls, for a bright, open layout with a large island. At the walkthrough we can tell you whether your room can grow inside the house or needs an addition.
We added a structural beam and wrapped it in dark rustic hardwood. The job also included a stone-faced corner fireplace and a built-in with a beverage fridge. Open the project to see every photo.
When the room you need isn't there, we build the addition. Ask about an addition.
Cost & timeline
What affects cost and timeline
Every addition is priced from its own plan, so we don't publish prices. Your estimate is itemized, so you can see what each part costs. The main things that move the number:
- Size and shape. More square feet and more corners mean more foundation, framing and roof.
- Foundation and site. The type of foundation, the soil, any slope and how easily equipment can reach the spot all matter.
- The roof tie-in. Joining a simple roofline is less work than joining a complicated one.
- What goes inside. A bedroom or family room is simpler than a kitchen or bathroom, which add plumbing, venting and more electrical.
- Heating and cooling. Your current system may need to be extended or upgraded to serve the new room.
- Matching the house. Siding, roofing and flooring that match what you have can take longer to find than new materials.
- Where old meets new. Opening the outside wall can show wiring, framing or water damage that needs fixing. If that happens, you see it on a written change order before we do the work.
An addition has more steps before construction than an interior remodel: drawings, engineering and permit review. After that, the schedule depends on inspections, lead times for windows and other materials, and weather during the foundation and framing work. We keep you posted as the schedule moves.
For budget questions and how to compare estimates, read our guide to planning a remodel.
Client reviews
Read all reviews
How clients say we run a job
Rated 5 out of 5
We wanted to open up our kitchen to the living room and kept getting vague answers from other contractors about ‘maybe needing a beam’. RSRT brought in an engineer, installed the LVL, and handled all the drywall and finish work so you’d never know a wall used to be there. The new kitchen layout is exactly what we sketched out, and they stayed on top of dust control so we could live in the house during the work.
Rated 5 out of 5
We bought a 90s house that needed everything on the main floor updated. RSRT handled wall removals, new LVL beams, kitchen re-layout, flooring, and trim. We always knew what was happening the next week and any changes were written down with clear pricing. Inspections passed the first time and the crew was respectful of our neighbors. The house feels brand new without weird shortcuts hiding behind paint.
Rated 5 out of 5
RSRT finished our unfinished basement and turned it into the most used part of our house. Framing, bathroom, bar, and an office were all done exactly how we talked about during the walkthrough. Alex kept us updated around inspections so nothing was a surprise. Clean crew, no drama, and the end result looks like it was always part of the house
FAQ
Home addition questions
Something else on your mind? Call (720) 392-4297 or ask in your estimate request.
Do you build home additions?
Yes. RSRT builds home additions, room additions and kitchen extensions. We run the build from the foundation, framing and roof to the finished interior. We handle permits and coordinate inspections where required. Tell us what plans or drawings you already have. At the walkthrough we explain what the job still needs.
Should I add on or rework the layout I have?
If you need more floor area, an addition is how you get it. If the space is there but walls are in the way, taking out a wall or a kitchen remodel may solve it without building out. Bring your must-have list to the walkthrough and we'll look at both.
What is a kitchen bump-out?
A small addition that pushes one kitchen wall out, often for an eating area, a bigger island or more counter space. A small bump-out can sometimes be built out from the existing floor framing, with no new foundation. A larger one needs its own foundation and roof tie-in, like any addition. The drawings and permit review settle which one your house needs.
Does an addition need a permit?
Yes. An addition needs a building permit, and the work is inspected in stages. We handle permits and coordinate inspections as each stage is ready.
How much does a home addition cost?
It depends on the size, the foundation, the roof tie-in, what goes inside and the finishes, so we don't quote from a price list. After the walkthrough you get a written line-item estimate that shows what each part costs. The estimate form has an optional budget range if you'd like to share yours up front.
Can we live at home during an addition?
Often, yes. The foundation, framing and roof are built outside the rooms you live in. The messier part is opening the old outside wall into the new space. We plan that step with you, protect floors and doorways and keep dust contained.
Which towns do you build additions in?
Boulder County, Broomfield and nearby towns, including Superior, Louisville, Boulder, Erie, Longmont, Westminster, Arvada, Thornton and Lakewood. See the service area.
Other services
More of what we build
Kitchen remodeling
Layouts, islands, cabinetry, counters, tile and lighting.
Learn moreLoad-bearing wall removal
Open the floor plan with a beam that carries the load.
Learn moreCustom home building
New homes built from the foundation up.
Learn moreBasement finishing
Bedrooms, baths, offices and media rooms below grade.
Learn moreWe also do deck building & repair. See recent projects or check the service area.
Free estimate
Need more room?
Tell us what the new space is for and add a few photos or plans. We usually reply within a few hours, set up a walkthrough at your home and follow up with a written line-item estimate.