Sunroom Contractor in Willowbrook, CA - Rooms You'll Actually Use Year-Round
South Gate Sunrooms & Patios is a sunroom contractor that turns Willowbrook patios, decks and old porches into rooms people use. We build sunrooms, enclosed patio rooms, screen rooms and patio covers here.

Single-story homes and back slabs in Willowbrook
Willowbrook is mostly houses, and most of the ones we see are single-story stucco homes on flat lots, a lot of them built a long time ago, with a concrete slab or a tired patio cover out back and a garage at the end of the drive. It's a short drive from our base in South Gate, and the houses look a lot like the ones we work on next door in Florence-Graham.
That shapes the job. The room usually ties into an older stucco wall and sits on a slab poured for a barbecue, not a room, so the first thing I look at is what's underneath.
Willowbrook permits go through the county
Willowbrook isn't a city, so there's no city hall in the picture. It's unincorporated, Los Angeles County acts as its local government, and LA County Public Works issues the building permits, so your room runs on the county's permit and inspection schedule more than on ours. Before you hire anyone, ask to see their California contractor's license, because a job that needs a building permit needs a licensed contractor. You won't find a city business license here either, since the county licenses the kinds of business on its own list. We're licensed and fully insured, and we check which office handles your address and take the permit steps off your hands.
The price moves mostly with the size of the room, glass versus insulated panels, and whether your slab can carry walls as it is. The start date moves with the county, so if plans have to be drawn first, I'll tell you early. It's the same way we work in Lynwood and the other cities near us, and your written estimate spells out what's in the number and what isn't.
Services in Willowbrook, CA
Enclosed patio rooms
Plenty of Willowbrook houses already have a covered slab out back that gets used twice a year. We close it in as one of our enclosed patio rooms, with windows that open, so you get a room without paying for a full addition.
Patio-to-sunroom conversion
When the slab is sound and you want a room you'll sit in come January, we convert the patio into a full sunroom with an insulated roof and walls tied properly into the house. I check the slab edges first, because an older patio wasn't poured with walls in mind.
Patio cover installation
Some backyards here just need shade on a hot afternoon, not walls. A patio cover is the cheaper answer then, and I'll say so before I sell you a room you'd rarely close up.
Screen room installation
A screen room suits people who want the breeze on summer evenings without the bugs. It costs less than glass and doesn't trap heat, though it won't keep winter rain off the furniture.
Four season sunrooms
If the room will be real living space, a four season room with an insulated roof, insulated walls and better glass is the one to build. It costs more up front, and it's the version you'll still want to sit in on an August afternoon.
Sunroom remodeling
We find older aluminum patio rooms here that leak where they meet the stucco or turn into ovens by noon. Remodeling one usually means new roof panels, better glass and fresh flashing at the wall, which costs less than tearing the whole thing out.
What Willowbrook sun and rain ask of a room
Summers here are warm more than brutal. A weather site's modeled estimates for Willowbrook, not readings from a station, put August highs around 80 with almost no rain, and that's still plenty to cook a glass room facing west. So I'd rather put a solid insulated roof over most rooms and save the glass for where you want the view. Winter is when the rain comes, a little over 3 inches a month in January and February by the same estimates, so we pitch the roof to shed water away from the house and flash it carefully where it meets the wall.
Older slabs are the other thing. A lot of back patios here have settled or cracked over the years, and sometimes we can build on one as it is and sometimes it needs new footings at the edge. I'll tell you which before you see a number.

Get a free estimate for your Willowbrook sunroom
Send the form and we'll reply within one business day to set a time. I come out to your Willowbrook house myself, look at the slab, deck or wall the room will tie into, and then you get a written estimate. It's free, and there's no obligation.
Working with us in Willowbrook
Call and set a visit
You call or send the form, and we set a time for me to come out. It helps if you're home, because I'll ask how you plan to use the room before I talk about what to build.
Get a written estimate
I look at what the room will sit on and tie into before I put a number on paper. The estimate says what's included and what isn't, so the price doesn't come with surprises tucked in.
We handle the permit steps
We take care of the county paperwork and book the inspections as each stage is ready. If plans have to come first, you hear about it early, because that's usually what sets the start date.
Build and walk the room
Our own crew builds the room, and I check on the work as it goes up. Before we call it done, I walk the finished room with you.
Willowbrook sunroom questions answered
Do I need a permit to add a sunroom in Willowbrook?
Yes. The county's permit guidance says additions need a permit, and adding a room and patios are both on its list of examples. We take care of the permit steps with the county for you.
How do I find out if my address is in unincorporated LA County or a city?
Look your address up in Z-Net, the tool the county's unincorporated area page points residents to. It matters because a house inside a city may go through that city's office for its permit instead of the county's. We check this before the estimate anyway.
When does a contractor need a California state license?
A contractor needs a state license when the job needs a building permit, uses any extra workers, or costs $1,000 or more in labor and materials. A sunroom almost always hits all three, so whoever builds yours should have one. We're licensed and fully insured.
How long do I have to get the first inspection after a county permit is issued?
The county says to request the first inspection within 12 months of getting the permit. After that, follow-up inspections come every 6 months to keep the permit active, so we book each one as soon as the work is ready for it.
How much does a sunroom cost in Willowbrook?
A Willowbrook sunroom's price comes down mostly to how big it is and how much of it is insulated. A screen room or patio cover sits at the low end, a four season room at the high end, and new footings, electrical or a tricky tie-in at an older stucco wall add to any of them. Your free estimate puts a written number on your house.
How do I ask the county what my sunroom project requires?
Contact your local county Public Works office, whose phone and email are listed in the county's Service Locator. The county tells applicants to do that to find out what a project needs. If you'd rather skip the phone call, we make it as part of the permit steps.
Ask about your Willowbrook room and permits
Call (213) 376-0861 any weekday until 11 PM, or send the form, and on the first visit I'll tell you whether a cover, a screen room or a full sunroom fits how you'd actually use it.





