i30 Builders · Residential
Room Additions in Rockwall and DFW
A bedroom, a bigger living room, a primary suite or a second living area, built onto the house so it looks and feels like it was always there.
Written scope and locked price before any deposit. One-year workmanship warranty.
Get a written estimate
Four fields. We call back within one business day to set up the site visit.
- GL + umbrella coverage
- $1M + $1M
- Workmanship warranty
- 1-yr
- Cities served
- 33
Who builds room additions in Dallas-Fort Worth?
i30 Builders, a general contractor based in Royse City, TX, builds room additions tied into the existing house, from engineered foundation to final inspection for homeowners across Dallas-Fort Worth, centered on Rockwall, Collin, Hunt and Kaufman counties. Each addition starts with drawings and engineering for the soil and the roof tie-in. Every job is measured and designed for the house, then priced in writing after a site walk, before any deposit, with permits handled.
- Pricing
- Written price after a site walk, before any deposit
- Permits
- Handled by us
- Warranty
- One-year workmanship warranty, in writing
- Where
- Dallas-Fort Worth, centered on Rockwall, Collin, Hunt and Kaufman counties
Updated
Start Here
An addition is decided where it meets the house.
The new room is the easy part. The hard part is the seam: where the new foundation meets the old one, where the new roof ties into the existing roof, and where the new walls open into the house. On North Texas clay, a new slab and a fifty-year-old slab move differently, and the joint between them has to be designed for it, not hoped over.
So an addition starts with drawings and engineering, not with a crew. We measure the house, check the setbacks and any HOA rules, size the foundation for the soil, work out the roof tie-in, and check whether the existing heating, cooling and electrical service can carry more house or need more capacity.
Then it is built in phases, each inspected before the next one covers it. You get the phases, the sequence and one written price before anything is dug.
How the planning works
Measured, drawn and picked before anything comes out.
Step 1
Measure and check the lot
Setbacks, easements, HOA architectural rules and where the utilities run. These decide how big the addition can be and where it can go before anyone draws a wall.
Step 2
Drawings and engineering
A plan set with the foundation designed for your soil, the roof tie-in, the framing, and the electrical and mechanical layout. This is what the city reviews and what the price is built from.
Step 3
Selections
Exterior materials matched to the house, windows, doors, flooring, lighting and trim, named in the scope so the price is for the room you picked.
Step 4
Phased build and inspections
Foundation, framing and dry-in, rough-in, insulation and drywall, finishes, and final inspection. The wall into the house opens as late as possible, so most of the work happens outside it.
Finish levels
Mid-grade or high-end, named by what goes in.
Most rooms mix the two. Tell us where you want to spend and where you do not, and the written scope names every material either way.
Mid-grade
- Slab foundation engineered for the soil, framed walls, shingle roof tied into the existing roof
- Siding or brick matched as close as the supply allows
- Vinyl windows, painted drywall, LVP or carpet
- A ductless mini-split for the new room
High-end
- Foundation and roof tie-in detailed so the seam disappears inside and out
- Exterior matched exactly, including trim profiles and brick blend
- Wood or fiberglass windows, hardwood or tile, custom trim and built-ins
- Ducted HVAC extended or upsized for the whole house
Code and permits
The rules that apply to this room.
- In Prosper, an addition of 400 square feet or more needs an energy report, and the town can require engineered plans for the foundation, wall bracing, ceiling and roof framing. Town of Prosper, Residential Remodel/Addition Permit Submittal
- Prosper requires any exterior wall within 5 feet of a property line to be built as a one-hour fire-rated wall, which matters when an addition reaches toward a side lot line. Town of Prosper, Residential Remodel/Addition Permit Submittal
- Denton requires a Texas engineer's seal on any foundation design over 400 square feet, and an energy code test form before the final inspection when the addition is heated and cooled. City of Denton, Residential Alteration or Addition Submittal Requirements
- In Plano, a house enlarged to 6,000 square feet or more must get an automatic fire sprinkler system. Covered patios and porches open on at least one side do not count toward that size. City of Plano, Ordinance No. 2025-6-15 (2024 International Residential Code with local amendments)
- Southlake requires a form survey on every addition, confirming the distances to the property lines at least 48 hours before the foundation inspection. City of Southlake, Accessory Buildings, Additions, & Remodels Guidelines
Read from the model codes on the dates linked. Each city adopts its own edition with its own amendments, so we confirm the rules for your address before we pull the permit.
Ready to get yours planned?
A free site walk, then a written scope and one price within five business days.
In every job
- Drawings, engineering and permit filing before construction
- A foundation designed for the clay, tied to the existing house as the engineer details it
- Roof tie-in and exterior matched to the house
- Electrical, mechanical and plumbing rough-in, inspected before walls close
- Insulation, drywall and finishes carried through from the existing rooms
- Final inspection, the punch list before final payment, and a one-year workmanship warranty
How we quote it
We do not publish prices or ranges. Every job is measured and built for your house, so a number off a website would be a guess.
A site walk, then a written scope back within five business days. The scope names the work, the materials and the price, and the price does not move unless the scope does.
Anything found behind a wall or under a slab that changes the work gets priced and approved before we touch it. That is a change of work, in writing, not a surprise on the final invoice.
Payment is by ACH, card, check or cash, on the schedule written into the contract.
What Moves the Number
Up and down, before you ask for a quote.
Pushes price up
- A second story, or an addition over an existing room
- Plumbing in the addition, such as a bathroom in a primary suite
- A complex roof tie-in or a vaulted ceiling
- An electrical panel or HVAC system with no room for more house
- Matching an older brick or siding that is hard to find
- Tight setbacks or a sloped lot that needs more foundation
Keeps price down
- A simple footprint on a flat part of the lot
- A roof line that extends the existing slope
- No plumbing in the new space
- A ductless mini-split instead of extending the ducted system
- Selections made before the drawings are final
Common Questions
Room Additions questions, answered
How do you price a room addition?
From the drawings. The plan set fixes the size, the foundation, the roof, the systems and the finishes, and the written price is built from that. Plumbing, a second story, the roof tie-in and whether your HVAC and panel can carry more house move it most. The price does not move unless the scope does.
Do I need a permit and an engineer for an addition?
Yes to the permit, every time: an addition is new structure and new living space. The foundation is designed for the soil, and in much of this area cities require an engineer's seal on foundations. We handle the drawings, the engineering and the filing, and schedule the inspections.
How do you tie a new foundation into an old one on clay?
As the engineer designs it, which usually means the new slab is built to work with the old one rather than lean on it. Clay swells and shrinks with moisture, and two slabs of different ages will not move together on their own. The detail at that joint is the most important line on the drawings.
How long does a room addition take?
Usually several months from signed drawings to final, as a range that depends on permit review, the size, the weather during foundation and framing, and selections. You get the phases and a range for each in writing before we start.
Can we live in the house during an addition?
Most people do. The addition is built outside the house for most of the job, and the wall between them opens near the end. When it does, the opening is sealed off and the paths through the house are protected.
Will my HVAC handle the extra space?
Sometimes. We check the existing system and the panel at the walk. A ductless mini-split for the new room avoids overloading an older system and gives the addition its own control. Extending the ducted system makes sense when the equipment has the capacity or is due for replacement anyway.
Do I need HOA approval for an addition?
If your neighborhood has an HOA, almost always, and it comes before the city permit. Most want the exterior to match the house and the addition inside the setbacks. We prepare the drawings and exterior selections for that submission.
Do you also convert garages and close in patios?
Yes. Those have their own pages, because they start from walls, a roof and a slab that are already there and run very differently from a true addition: garage conversions, and sunrooms and patio enclosures.
Keep reading
Read before you build
Built here, rules here
Rules where you live
Height limits, setbacks, permit triggers and fees change at every city line, and so does the ground. Each page below is one city or county: its rules read from its own code, and what its soil does to a post or a pier.
Prefer to give us the details now?
Tell us what you want built and roughly how big. We walk it, then price the scope in writing, and the price does not move unless the scope does.
indicates a required field
Step 1 of 2: Project info