Additions and ADUs in Longmont, CO
Space for the People Your Home Has Been Waiting to Welcome
Why Longmont Homeowners Choose Christie's
Because the Home You've Outgrown
Has More Room in It Than You Think
For more than 25 years, Christie’s has helped Longmont homeowners turn the equity sitting in their current home into something their family can actually live in, a garage that’s been storing dusty gear for a decade, finally converted into a two-level ADU with a real kitchen and a mountain view from the balcony. A second-story addition on a ranch that doubles your square footage without touching the backyard. A private in-law suite where your parent has their own entrance and their own space, just close enough.
At Christie’s Design/Build Remodeling, we start by asking what your Saturday morning looks like right now, and what you wish it looked like. We know Longmont’s updated ADU regulations, we know what a pre-1990 panel usually needs before a garage conversion can move forward, and we know how to tell you the honest all-in number before you’ve committed to anything. From Kensington ranches to Old Town bungalows and established neighborhoods near McIntosh Lake, we plan around the home you already have.
In Business
25+ Years
Helping Longmont homeowners convert underused garages, ranch footprints, and untapped square footage into real, independent living space for the people who matter most.
Our Model
One Team
Your Longmont addition or ADU is guided by one coordinated team from garage assessment and design through permitting, construction, and final walkthrough.
Where We Work
Longmont, CO
Serving homeowners throughout Kensington, Old Town, Somerset Meadows, McIntosh Lake, and established neighborhoods across Longmont.
Peace Of Mind
5-Year Warranty
Your new Longmont addition or ADU stays covered after construction ends, so you can settle into the space without worry.
What Makes Additions & ADUs Different In Longmont
The Space You Add
Should Feel Like It Was Always Home
Adding onto a Longmont home means you’re starting with a specific set of conditions, a ranch footprint that hasn’t grown since 1978, a detached garage that’s been storing bikes instead of housing your parent, and lot setbacks that may quietly redirect your first-choice detached ADU toward an attached suite or basement configuration. The families we work with here have usually been thinking about this for a while, and the question that comes up every time is what the project actually costs when you include permits, utility runs, and the panel upgrade that most pre-1990 homes in Kensington and Loomiller need. At Christie’s Design Build, we put all of that on the table before design begins, six-week plan check, utility connection feasibility, lot coverage math, so the number you see is the real one. The goal is an addition or ADU in Longmont, CO that earns its square footage and fits the home so naturally that it’s hard to tell what was always there and what you built.
.01
Longmont Ranches Have Real Bones
.02
Your Ranch Lot Sets the Starting Point
.03
Pre-1990 Panels Need a Real Look
.04
Longmont's Climate Drives Every Material Choice
Longmont, CO Neighborhoods
More Room Without Leaving
the Longmont You Already Call Home
Longmont is full of homes that families bought before the price run-up, 1970s and 1980s ranches in Kensington or off the older residential grid, with detached garages that have solid bones and zero plumbing, sitting twenty feet from the back fence doing nothing useful. Some households need a fully independent space for a parent who wants their own front door, their own kitchen, and the dignity of coming and going on their schedule. Others have an adult child back in the picture, or a caregiver who needs somewhere permanent that isn’t a guest room. Longmont’s updated ADU regulations make the path through permitting more navigable than it was even two years ago, but your specific lot, its setbacks, coverage limits, and utility connections still shape what’s actually possible before design begins. We start every conversation by asking what your family genuinely needs from this space, then work backward from that answer to find the right fit for the home you already own.
Somerset Meadows
When a Well-Built Home Still Has More to Offer
McIntosh Lake
Add the Space You're Missing Without Losing the View That Sold You
Clover Creek
When the Family Outgrows the Floor Plan You Loved
Terry Lake
Build Space for the People Sharing Your Life
Prospect New Town
Build the Space This Neighborhood Was Designed to Grow Into
Our Longmont Additions & ADU Process
From the First Conversation to the Day They Move In
Adding an addition or ADU in Longmont brings questions that are specific to this city, a detached garage with solid bones but no plumbing, a ranch footprint that’s been carrying your family for thirty years, a lot where setbacks may quietly rule out your first idea before design ever begins. A home near Old Town has a completely different set of considerations than a newer build in Somerset Meadows. Our process walks each project through site evaluation, design, permitting, utility coordination, construction, and final completion, one clear track so you always know where things stand.
.01
Site & Structure Review
.02
Goals & Design Direction
.03
Detailed Project Planning
.04
Permits & Trade Coordination
.05
Construction & Communication
.06
Final Review & Completion
Our Longmont Additions & ADU Process
From the First Conversation to the Day They Move In
Adding an addition or ADU in Longmont brings questions that are specific to this city, a detached garage with solid bones but no plumbing, a ranch footprint that’s been carrying your family for thirty years, a lot where setbacks may quietly rule out your first idea before design ever begins. A home near Old Town has a completely different set of considerations than a newer build in Somerset Meadows. Our process walks each project through site evaluation, design, permitting, utility coordination, construction, and final completion, one clear track so you always know where things stand.
.01
Site & Structure Review
.02
Goals & Design Direction
.03
Detailed Project Planning
.04
Permits & Trade Coordination
.05
Construction & Communication
.06
Final Review & Completion
What Longmont Homeowners Want From Their Addition or ADU
More Room for the
People Who Matter Most
Space for Every Generation
Space That Earns Its Place
In Longmont's established neighborhoods like Kensington and Loomiller, most ranches were built for households a fraction of today's size, and without the multigenerational configurations families now need. A thoughtful addition or garage conversion can create a genuinely independent suite, open the main living area, or finally give a parent their own front door without leaving the home you already love.
Designs That Shift With Life
Room Already Within Reach
Many Longmont ranches are carrying floor plans that made sense decades ago but feel like a daily frustration now. Rethinking how old and new space connect, with real flow and no awkward transitions, is where these projects start feeling like home again.
Garage Space That Finally Works
Independence Right Out Back
Longmont's larger established lots give you room to solve more than just square footage with the right addition. Built-in storage, a dedicated mudroom, and a properly planned laundry space make the finished area feel calmer and genuinely easier to live in.
Their Own Space, Your Yard
Close, With Their Own Door
For homeowners in Kensington and around McIntosh Lake, a garage conversion or attached in-law suite can make multigenerational living feel genuinely sustainable rather than improvised. A private entrance, a full kitchen, and independent climate control change how the whole arrangement feels, for everyone involved.
Built for Front Range Winters
Designed for Longmont's Real Life
Longmont additions have to hold up against freeze-thaw cycles, hail seasons, and hard winters that test every exterior connection and roofline seam. Exterior cladding, insulated envelope details, and interior finishes chosen for real Front Range conditions keep the new space performing and looking exactly the way it should.
What To Consider When Building An Addition or ADU In Longmont
Plan for the Space Your Longmont Home
Was Always Meant to Hold
Who is this space really for, and what does their day actually look like inside it?
Does your detached garage have what it takes to become the space you're imagining?
Have you checked whether your lot and HOA both actually allow what you're planning?
How do you want the space to feel five years after the last crew leaves?
Our Reviews
Trusted by Longmont Homeowners
With the Spaces Their Families Live In
Areas We Service Across Longmont
Space to Stay
Right Here in Longmont
- Ralston Valley
- Oberon
- Pomona Lakes
- Whisper Creek
- Spring Mesa
- Olde Town Arvada
- Allendale
- Lake Arbor
- Scenic Heights
- Alta Vista
- Club Crest
- Hackberry Hill
Other Areas We Service
Weld County
Boulder County
Adams County
Jefferson County
Broomfield County
Larimer County
Longmont Addition & ADU Frequently Asked Questions
The Questions Behind
Getting the Space Your Family Actually Needs
How do Longmont's updated ADU regulations affect what I can build on my lot?
Can my detached garage actually become a fully independent ADU, with its own kitchen, bathroom, and laundry?
How long does the permitting process take for a home addition or ADU in Longmont?
Do I need HOA approval before going to the city for a permit?
What's the difference between converting my existing garage and building a brand-new detached ADU from the ground up?
Can we stay in the house while the addition or ADU is being built?
Will a second-story addition on my ranch home require structural work beyond what I'm expecting?
What happens if my lot can't support a detached ADU, are there other options?
Start The Conversation
Build the Space
Your Longmont Family Has Needed
Our Other Remodeling Services
From The Blog
That Longmont Garage
Could Be Home for Someone You Love

