Bedrooms · family rooms · offices
Room Additions in the Phoenix Valley
When a house gets too small, the usual advice is to move — and moving means transaction costs on both ends, a higher interest rate than the one you may be sitting on, new schools, and leaving a neighborhood you chose on purpose. A room addition is the other answer: keep the house, the street, and the school enrollment, and build the space you're missing onto the home you already own. Masizo Development builds additions across the Phoenix Valley — Gilbert, Mesa, Chandler, Queen Creek, San Tan Valley, Tempe, Scottsdale, Phoenix, Fountain Hills, and Paradise Valley — as a licensed Arizona general contractor (AZ ROC #336058) with 28 years of experience, handling permits, foundation, framing, and systems with our own project oversight from first sketch to final inspection.
- 28 years · since 1998
- AZ ROC #336058
- AZ ROC #347030
- CA LIC #1107781
- IICRC certified
- Insured
- BBB A+ accredited
The matching test
The Test of a Good Addition: You Can't Find It
Everyone has seen a bad addition. The roofline that meets the original roof at an angle no architect would draw. The stucco patch in a slightly wrong texture. The step down at a doorway where two slabs never agreed on a height. Those tells do worse than look awkward — a visibly tacked-on room can work against a home's value instead of adding to it.
So we treat matching as a design requirement, not a finishing touch. Before we draw anything, we study how your house is built: the roof pitch and material, the exterior finish and its texture, the window style and trim, the interior floor heights. The addition is then engineered to continue those lines — roof planes that resolve naturally, exterior finish blended across the joint, and floors that meet flush. The goal is a room that a visitor, an appraiser, or a future buyer reads as original construction.
What we build
What We Build
Bedroom Additions
The most common call we get: the family outgrew the bedroom count, and nobody wants to change schools over it. We build bedroom additions as complete private spaces — many with an attached bathroom and a walk-in closet — placed where your lot and setbacks allow, and permitted and inspected like the habitable space they are. A well-planned bedroom suite can carry a house through a decade of family growth for far less upheaval than a move.
Family Rooms, Dens, and Home Offices
Living-space additions are about how the house functions day to day: a family room big enough for everyone at once, a den that gives the household a quiet second living area, or a home office with a door that actually closes — a different thing entirely from a desk in the dining room. These rooms invite built-ins, media walls, and extra natural light, and we design that into the structure rather than bolting it on afterward.
Additions Combined With a Remodel
An addition changes how the whole floor plan flows, and it's often the natural moment to fix what the original layout got wrong. Opening a wall between the new family room and a cramped kitchen, or pairing a bedroom addition with a remodel of the hall bath it will share, costs far less as one project than as two. We run the combined scope on a single contract — one crew, one schedule, one number to call — instead of leaving you to referee two contractors occupying the same house.
Structure & systems
The Parts You Don't See Are the Parts That Matter
An addition is structural work. It needs its own foundation, tied correctly to the existing slab; framing engineered to carry its roof and connect soundly to the original structure; and a roof tied in so the junction sheds water for decades, because in Arizona the monsoon will find any shortcut eventually. Our crew handles the foundation and framing ourselves — this is the skeleton of the project, and we don't subcontract our accountability for it.
Just as important, the new room has to work like the rest of the house. That means electrical extended with the panel's capacity confirmed, plumbing routed properly where a bathroom is involved, and HVAC that actually conditions the space — an addition that swelters every July because nobody sized the ductwork is a Valley cliché we refuse to build. We tie in all three systems as part of the base scope, not as change orders.
Permits & HOAs
Permits, HOAs, and Setbacks — Handled Before They're Problems
Every city we work in requires a permit for an addition, without exception. We prepare the plans and permit package, file them, answer the city's plan-review comments, and schedule every inspection — foundation, framing, systems, and final — so the project never sits waiting on paperwork. If you have an HOA, its architectural rules get checked at the consultation along with your lot's setback lines, because where the room can go is a fact to establish on day one, not week six.
Living through it
Living There While We Build
Most clients stay home during an addition, and we sequence the work to make that livable. The foundation, framing, roof, and exterior shell all go up outside your walls; your house stays closed, secured, and functioning. Only near the end do we open the shared wall to connect the new room — as late in the schedule as the work allows — and we contain dust at that opening while the connection is made. You'll know the plan and the timing of that step in advance, because surprises are for parties, not construction.
Timeline & budget
What Shapes an Addition's Timeline and Budget
Two additions of identical square footage can be very different projects, and it helps to know why before you collect bids. On the schedule side, the big variables are permit review time in your city, the complexity of the roof tie-in, and whether the addition carries plumbing — a bedroom with a bathroom involves trades and inspections a den does not. On the budget side, the drivers are the foundation and structural work, how far electrical and HVAC have to travel from your existing systems, the exterior matching scope, and your finish selections inside the room. None of this is a reason for vague pricing: once we've walked your home, every one of those variables has an answer, and they all appear as plain line items in the written quote rather than as padding hidden in a lump sum. If the numbers point toward a garage conversion or a detached unit instead, we'll say so — that path is covered on our ADU page.
Addition vs. ADU
Addition or ADU? The Honest Comparison
Some families come to us asking for an addition and leave planning a casita — or the reverse. The distinction is simple: an addition makes your home bigger; an ADU is a second, self-contained dwelling on the same lot, with its own entrance and bath, that can house a relative independently or earn long-term rent. Arizona law now requires many Valley cities to allow ADUs on single-family lots — our Arizona ADU law guide explains the rules — and our ADU construction page covers casitas, garage conversions, and in-law suites in depth. Because we build both, the consultation is a comparison, not a pitch: we'll lay out what each path costs and does on your lot, and you choose.
Next step
Start With a Free Consultation
We come to your home, walk the lot and the rooms, look at where the addition can go, check HOA and setback constraints, and talk through how you want the space to live. You get a clear written quote, and any change after that is priced in writing before work proceeds. See completed projects in our portfolio, read client reviews on our testimonials page, or confirm your city on the service areas page.
Masizo Development — licensed (AZ ROC #336058, CA LIC #1107781, AZ ROC #347030), insured, and building in Arizona for 28 years. Call (602) 909-7630, email office@masizodevelopment.com, or request your free quote.
Good to know
Addition questions, answered.
Do I need a permit for a room addition?
Yes — every Valley city we work in requires a permit for an addition, because you're adding foundation, structure, and usually electrical, plumbing, or HVAC. We prepare and file the permit, coordinate with the city through plan review, and schedule each required inspection as the build progresses. The permit also protects you later: unpermitted additions surface at the worst possible time, usually during a sale.
Will my HOA need to approve the addition?
If you have an HOA, almost certainly — an addition changes the exterior of the home, which is exactly what HOA architectural rules exist to review. We look at your CC&Rs during the free consultation and help prepare what the HOA's review committee typically asks for, so that approval runs in parallel with design instead of stalling it.
Can you match my existing roofline and stucco?
That's the test of a good addition, and it's a point of pride for us. On the first visit we study your roof pitch and material, your stucco texture or siding profile, and your interior floor heights, then design the addition so the new work reads as original construction — no awkward roof transition, no visible seam in the finish, no step up at the doorway.
Can we live in the house during construction?
Usually, yes. Most of an addition is built from the outside: foundation, framing, roof, and exterior shell all happen before the house itself is opened up. We cut through the shared wall as late in the schedule as possible and contain the dust when we do, so the disruptive stretch is measured in days, not the length of the project.
Should I build an addition or an ADU?
They answer different questions. An addition makes your main home bigger — one more bedroom, a larger family room — all inside the same household. An ADU is a separate dwelling with its own entrance and bathroom that can house a relative independently or be rented long-term. If the new space will always be part of your home, add on; if it needs its own front door, build an ADU. We construct both, so you'll get an honest comparison for your lot, not a sales pitch for either.
Are you licensed and insured?
Yes. Masizo Development is an Arizona licensed general contractor (AZ ROC #336058), licensed in California as well (CA LIC #1107781), holds a separate Arizona restoration license (AZ ROC #347030), and is insured. We've built in Arizona for 28 years, and our licenses are verifiable with the Arizona Registrar of Contractors.