Additions - JJ Builders

Home Additions in Riverside, CA

A bigger kitchen, an extra bedroom, a master suite, a second story — built so the new part of your home looks like it was always there.

What are Home Additions?
A home addition is one of the highest-return projects you can do — but only if the finished result doesn't look bolted on. The walls have to align. The roofline has to flow. The siding, the trim, the windows, the interior trim profiles all have to match. That's the difference between an addition that increases your home's value and an addition that becomes the thing future buyers want to remove. JJ Builders has been adding to homes across Riverside for 18 years. We treat every addition as if we built the original house — and we build the new part to last as long as it.
, JJ Builders
Why Riverside homeowners hire us for additions

Most additions involve three hard problems most contractors aren't great at solving:

01
Matching the existing structure

Roof pitch, foundation type, framing dimensions, electrical capacity, HVAC sizing — all have to be evaluated and respected. Wrong on any of these and you're either over-engineering (paying too much) or under-engineering (creating a future problem).

02
Permits for additions

Setbacks, lot coverage, height limits, neighbor sightlines, HOA approvals — every Riverside city has different rules. Getting this wrong adds months.

03
Living through it

Most additions happen while you're still in the home. We phase work, build temporary weather barriers, and protect your existing rooms so the disruption stays manageable.

We've solved all three across hundreds of additions. You'll get a clear plan, a permit-ready set of drawings, and a build sequence that respects your house and your family.
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What you get when you hire us
How We Work
01
Discovery (15 minutes, free)

What you're adding, why, and what you're working with. Free, no pressure.

02
Site Visit & Feasibility

We come look at the house and the lot. Setbacks, structural realities, utility access, roof tie-in points, HOA constraints — all evaluated before design starts.

03
Design & Permits

Architectural drawings, engineering, energy compliance. We submit to the city, manage comments, and get to permit issue. Typically 6–12 weeks depending on complexity and city.

04
Build

Foundation, framing, roof tie-in, mechanical, electrical, plumbing, finish work. Most additions take 3–6 months from groundbreak. You get weekly site walkthroughs and daily updates through Houzz Pro.

05
Walkthrough & Warranty

Final inspections, professional cleanup, written workmanship warranty (2 years standard, 5 years on luxury-tier additions), and a punch list closeout.

Diego Cruz-Baker
Diego Cruz-Baker3 months ago
★★★★★
5 stars without hesitation. We've had the pleasure of seeing JJ Builders' work firsthand on an ADU project, and it was truly impressive, top-notch craftsmanship…
Ryan Dodson
Ryan Dodson12 months ago
★★★★★
Top notch service and creativity. Josh Phillips has an unbelievable talent for building. Thank you very much for the creative ideas and help with our ADU build.…
Matthew Baltazar
Matthew Baltazar1 year ago
★★★★★
HUGE SHOUTOUT to Joshua at J.J Builders. They ensure your project is done quickly, professionally, and efficiently. Biggest thing I appreciate is the constant c…
Gabriela Devine
Gabriela Devine1 year ago
★★★★★
I proudly recommend Josh and JJ.Builders! We needed some work done on our personal property and not only did he make sure everything was handled great from star…
David Fontes
David Fontes1 year ago
★★★★★
JJ builders were great they helped us build an A.D.U. Joshua Phillips was very helpful and kept us informed the whole way. Our kitchen remodel was a huge succes…
Wendy Lominario
Wendy Lominario1 year ago
★★★★★
Had a new shower door installed. Joshua was wonderful. Answered all text messages right away. Gave me different options and explained everything in detail. He c…
Ruth Hamad
Ruth Hamad1 year ago
★★★★★
Love jj builder very efficient reasonable priced fast beautiful work. I used them twice, both times they did excellent job. Recommend them without any hesitatio…
David Bower
David Bower1 year ago
★★★★★
This is a first rate builder. You will never be surprised except for the high quality of his work.
Luis Rodriguez
Luis Rodriguez1 year ago
★★★★★
Excellent experience overall. I really appreciate the expertise and knowledge explained to me during the process. Communication was A+. Don't hesitate to use th…
Duke Vu
Duke Vu1 year ago
★★★★★
I had the pleasure of working with Josh for a home improvement project, and I cannot recommend him highly enough! From start to finish, Josh showcased his exten…
David Bower
David Bowera year ago
★★★★★
This is a first rate builder. You will never be surprised except for the high quality of his work.

The Results Speak
for Themselves

Every project is designed to last, crafted with precision, managed with discipline, and finished with care. From modernized spaces to full custom homes, we deliver work that looks as good as it feels to live in.

What homeowners love about our builds:

Most Common Questions

Frequently asked questions

We serve Riverside County and surrounding Inland Empire communities, including Riverside, Rancho Cucamonga, and nearby areas. Staying local helps us keep schedules tight and communication easy.

Yes, we design and build custom homes, accessory dwelling units (ADUs), and additions from the ground up. Expect clear pricing, detailed schedules, and craftsmanship that lasts.

Absolutely. We specialize in whole home remodels, kitchen and bath upgrades, and layout improvements that make your home feel new again, without the stress or mess.

We provide transparent estimates early, with written change orders and frequent check-ins so you always know where your project stands.

We’re a local, experienced general contractor focused on quality, cleanliness, and accountability, protecting your home, your budget, and your peace of mind from day one.

Thinking about adding to your home? Let's plan it right.
Whether you have a clear vision (extra bedroom for a new baby, master suite expansion, second-story add) or you're still figuring out what's possible on your lot, a 15-minute call is the right first step. We'll talk through your goals, your timeline, your lot constraints, and what your project realistically costs.