Small ADU and Cottage Plans in Colorado: Guest House, Mountain Cottage & Affordable Family Home Blueprints

Looking for small ADU and cottage plans in Colorado for a parent, a rental or a mountain getaway? You are in the right place. At HousePlans USA, we draw backyard ADUs, guest houses, mountain cottages and affordable family homes from scratch. Every plan fits your lot, your city's rules and Colorado's snow and energy codes. Moreover, plans start at just $1,050 for homes up to 1,000 square feet.

Colorado housing costs have climbed sharply over the last decade. In fact, many families in Denver, Boulder and Colorado Springs now struggle to find homes they can afford. Meanwhile, the state and many cities have changed their rules to make accessory dwelling units easier to build. Consequently, small homes are one of the smartest ways to add housing, income and flexibility. However, a small Colorado home still has to handle heavy snow, cold winters, expansive soils and strict energy codes. Therefore, our designers treat small homes with the same care as large ones.

You choose your size, rooms and style online. Next, two or more designers sketch concepts for your lot. Then, you pick your favorite. You can start your small home design in about ten minutes. Additionally, customization is always included in the price.

Why Coloradans Are Building ADUs and Cottages

Small homes cost less to build, heat and maintain. However, the benefits go far beyond price. Consequently, more Colorado homeowners add an ADU or build a cottage every year.

Family Close By

Many Colorado families care for aging parents or support adult children who cannot afford rent. Therefore, a backyard ADU lets relatives live close but independently. Similarly, a guest house welcomes visitors during ski season and summer holidays. Everyone keeps privacy, yet help is only a few steps away.

Rental Income in Expensive Markets

Rents in Denver and Boulder are among the highest in the Mountain West. Consequently, a well-designed ADU can earn meaningful monthly income. Long-term tenants, students and healthcare workers all seek small, comfortable units. Always check local short-term rental rules, however, because many Colorado cities restrict them.

Changing Rules Make It Easier

Colorado has moved to encourage more housing. For example, a 2024 state law requires many larger cities to allow ADUs on single-family lots, with limits on how strictly they can regulate them. Additionally, Denver, Boulder and Colorado Springs have all updated their own codes. As a result, many lots that could not hold an ADU a few years ago now can. Learn more on our Colorado building requirements page.

Our Services: Small ADU and Cottage Blueprints in Colorado

Each service below is drawn to order for your county and lot. Prices start at $1,050, and most ADUs and cottages fall in our first two price tiers. See every option on our pricing page.

Small ADU Cottage Plans in Denver

Denver has expanded where accessory dwelling units are allowed across the city. Therefore, many homeowners buy small ADU cottage plans in Denver for lots in Highland, Berkeley, Park Hill, Platt Park and Baker. Many Denver lots have alleys, which makes a garage ADU especially practical. The garage sits on the alley, and the apartment sits above it with a private entry.

A detached one-bedroom cottage of 500 to 750 square feet is another favorite. It includes a full kitchen, a bathroom and a small porch. Additionally, we design to Denver's height, setback and bulk plane rules from the start. See our Denver building guide and our Denver house plans guide.

Denver's energy code is demanding. Consequently, even small units need strong insulation, efficient heat pumps and careful air sealing. We include those details, so your plan passes review smoothly.

Small Guest House Plans in Colorado Springs, CO

Colorado Springs updated its rules to allow ADUs in more neighborhoods. Therefore, many homeowners buy small guest house plans in Colorado Springs, CO for lots in the Old North End, Patty Jewett, Westside and Broadmoor. Military families near Fort Carson, Peterson and the Air Force Academy often need flexible housing for visiting relatives.

A guest house here often has a mountain cottage feel, with stone accents and a covered porch facing Pikes Peak. Moreover, snow loads and wind on the west side require careful roof design. See our Colorado Springs building guide and our Colorado Springs house plans guide.

Affordable Family Home Plans in Woodland Park, CO

Woodland Park sits at about 8,500 feet in Teller County, west of Colorado Springs along Ute Pass. It offers mountain living with Pikes Peak views and lower prices than many mountain towns. Therefore, many families buy affordable family home plans in Woodland Park, CO. A three-bedroom, two-bath home of about 1,500 square feet over a basement is a popular choice.

At this elevation, snow loads are heavy and winters are long. Consequently, we design strong roof framing, simple roof forms and well-insulated walls. Additionally, wildfire rules apply in the surrounding forest, so we specify ignition-resistant materials. Browse our cabin house plans for mountain styling.

Small ADU Floor Plans in Boulder, Colorado

Boulder has steadily loosened its ADU rules to help with housing costs. Therefore, many homeowners buy small ADU floor plans in Boulder, Colorado for lots in Whittier, Mapleton Hill, Martin Acres and North Boulder. Students, university staff and young professionals create steady rental demand.

Boulder's energy code is among the strictest in the country. Consequently, even a small ADU needs very high-performance walls, windows and mechanical systems. Many owners also add rooftop solar. See our Boulder building guide and our Boulder house plans guide.

Mountain Cottage Plans in Louisville, CO

Louisville sits between Boulder and Denver, with a charming historic downtown. Many families here are rebuilding after the 2021 Marshall Fire. Therefore, many clients purchase mountain cottage plans in Louisville, CO for efficient, fire-resistant homes. Metal roofs, fiber cement siding and ember-resistant vents are common requests.

Cottages here often blend craftsman details with modern efficiency. For example, a deep front porch and exposed rafter tails pair with triple-pane windows and a heat pump. Browse our cottage house plans and craftsman house plans.

Garage Apartments Along the Front Range

Garage apartments are one of the most efficient ADU types. A two-car garage below supports a one- or two-bedroom apartment above. Consequently, you add housing without giving up yard space. This layout works especially well on alley lots in Denver, Englewood and Colorado Springs.

Garage apartments need fire separation between the garage and the living space. Therefore, we specify rated walls and ceilings. Additionally, an exterior stair with a covered landing keeps snow off the entry.

Affordable Starter Homes Across Colorado

Not every small home is an ADU. Many clients simply want an affordable first home. Therefore, we draw compact two- and three-bedroom homes for lots in Pueblo, Greeley, Fountain and Brighton. A simple footprint over a basement keeps costs down while providing room to grow.

Starter homes can expand later. For instance, an unfinished basement can become two bedrooms and a family room when your budget allows. We show the future layout now, so plumbing rough-ins go in during construction.

How ADU Rules Differ Across Colorado Cities

Colorado's new state law sets a floor, but each city still has its own details. Therefore, a plan that works in Denver may need changes in Boulder. Always confirm current rules with your local planning office.

Denver

Denver allows ADUs in many residential zones. However, height, setback and bulk plane rules apply. Consequently, detached ADUs are often one and a half or two stories with careful roof shapes. Alley-facing garage ADUs are especially common, because they keep the backyard open for the main house.

Boulder

Boulder allows ADUs on many lots, with size limits tied to the lot and main home. Additionally, its energy code requires very high performance. Therefore, Boulder ADUs often cost a little more per square foot but save a lot on energy. Over time, lower utility bills help offset the higher upfront cost.

Colorado Springs

Colorado Springs allows ADUs in more zones than before. However, HOA covenants may still restrict them. Consequently, we check your HOA rules as well as city code. Older neighborhoods without HOAs usually offer the most flexibility for backyard cottages.

Mountain Towns

Mountain towns often have strict short-term rental rules and steep-slope requirements. Therefore, we review local rules before concepts begin. Some towns also require deed restrictions that keep ADUs available for local workers, which can affect your rental plans.

Designing Small Homes for Colorado's Climate

Snow and Roof Design

Snow loads rise with elevation. Consequently, we design simple roof forms that shed snow away from doors and walkways. Covered entries also keep snow off steps. Additionally, we keep roof valleys and dormers to a minimum, because complex roofs trap snow and ice.

Energy Efficiency

Colorado winters are cold, and energy codes are strict. Therefore, we specify thick insulated walls, efficient windows and heat pumps. A 2x6 wall upgrade costs only $175 on the plans. Moreover, a small heat pump with a backup heater keeps an ADU comfortable through cold snaps without a large furnace.

Expansive Soils

Even small homes need good foundations on Front Range clay. Consequently, we coordinate with your soils report and engineer when required. A structural floor or drilled piers may be needed, even under a garage apartment.

Smart Design Ideas for Colorado ADUs

Lofts and Vaulted Ceilings

Height makes small rooms feel larger. Therefore, we often vault the living area and add a sleeping or storage loft. Big windows frame mountain views. A sleeping loft can also add space for guests without adding footprint.

Built-In Storage

Every inch counts. For example, a window seat can hide storage, and a pocket door saves swing space. Similarly, a stacked washer and dryer fits a small closet. Open shelving and under-stair drawers keep a compact kitchen feeling airy and organized.

Gear Storage

Coloradans have gear. Consequently, a small mudroom or exterior storage closet for bikes and skis is a smart addition. A wall-mounted bike rack and a boot tray near the door keep the small living area clutter-free.

Popular ADU Layouts in Colorado

Most of our Colorado ADUs follow one of three layouts. Each one solves a different need. Therefore, we start by asking who will live in the unit and how long they plan to stay.

The Studio Cottage

A studio runs about 400 to 500 square feet. It combines living and sleeping in one bright room, with a compact kitchen and a full bathroom. Consequently, it suits a home office, a guest suite or a single tenant. It is also the most affordable layout to build and heat.

The One-Bedroom Cottage

A one-bedroom cottage runs about 550 to 750 square feet. A separate bedroom adds privacy for longer stays. Additionally, a small covered porch gives the resident an outdoor room of their own. This is our most popular layout for parents moving closer to family, so we often add a curbless shower and wider doors.

The Two-Bedroom Garage Apartment

A two-bedroom apartment above a garage runs about 800 to 1,000 square feet. It suits a small family or two roommates. Moreover, it earns the highest rent of the three layouts. However, it needs a code-compliant stair and fire separation from the garage below. A covered landing at the top keeps snow and ice off the entry all winter long, which tenants appreciate.

Areas We Serve Across Colorado

We draw ADU and cottage plans for every county. In the Denver metro, we serve Denver, Englewood, Lakewood, Arvada, Aurora and Littleton. In Boulder County, we serve Boulder, Louisville, Lafayette, Superior and Longmont.

Around Colorado Springs, we serve the Old North End, Broadmoor, Manitou Springs, Woodland Park and Fountain. We also serve Fort Collins, Greeley and Pueblo. Want a larger home? Read our guide to ready to build house plans in Colorado. Building on a slope? See our walkout basement plans in Colorado.

Budget Tips for Small Colorado Homes

First, keep the shape simple with one roofline. Second, place the kitchen and bathroom back to back. Additionally, choose PDF unlimited build rights for $395 if you plan to build the same ADU more than once. We also offer a $29 cost-to-build report and a $295 custom material list. As a result, you can price your project before calling builders.

Why Colorado Buyers Choose HousePlans USA

Real Choices From Real Designers

Two or more designers sketch concepts for your lot. Consequently, you get fresh ideas, not a recycled plan.

Free Customization and Revisions

Your instructions are included. Moreover, you get 30 days of free revisions after delivery.

Complete Permit Options

We offer Colorado engineer stamps, energy code reports and CAD files. Questions? Contact our team any time.

How Ordering Works

First, choose your size and rooms in our online designer. Next, review concepts from several designers. Then, pick your favorite to draw the full set. You pay a 75% deposit to start, and the rest when your final plans are ready. Explore our ADU and small house plans by state guide and every house style.

Frequently Asked Questions

Start Your Colorado ADU or Cottage Today

Your small Colorado home can make a big difference. Whether you want a Denver garage ADU, a Boulder backyard cottage or a Woodland Park family home, we can draw it. Call or WhatsApp us at +1 (217) 426-5403, or start your free quote today. Browse our interior design ideas and our full blog.