Accessory Dwellings · Colorado
Accessory dwellings, built as architecture.
Limestone Custom Homes designs and builds luxury custom ADUs in Castle Rock, Douglas County, and across Colorado. Detached new construction, attached additions, garage conversions, and private studios. each an extension of the primary home, not an afterthought.
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i. Practice
An ADU is a second home. It should look like one.
Most accessory dwelling units are treated as utility structures or a back of the lot solution to a programmatic problem. Limestone treats an ADU the same way we treat the primary residence, as a permanent piece of architecture attached to its lot and built to the same standard as the main house.
Some clients want the ADU to share the architectural language of the primary home materials, proportions, and roofline so the property reads as a single composition. Others want the opposite, a modern studio behind a traditional house, a timber retreat beside a stone residence, a building with its own character entirely. Both are legitimate briefs. What matters is that the relationship between the two buildings is drawn deliberately, not left to chance.
We do not assemble kits or prefab units. Every ADU build is designed for its specific lot by a single team.
Why an ADU, and why now
ADUs have moved from a niche request into an architectural mainstay in Colorado for three reasons. Adult children are returning home longer. Aging parents are moving onto family land instead of into care facilities. And the long-term rental market has made the unit pay for itself.
ii.Forms
Types of ADU.
01 —
Detached new construction
A standalone structure, purpose-built, matched to the primary residence or drawn with its own character. The most common form when the lot allows, and the form with the longest useful life.
02 —
Attached addition
An ADU built as an extension of the primary home, with a private entrance and self-contained kitchen and bath. Works well where the lot does not accommodate a detached unit or where multigenerational proximity is preferred.
03 —
Garage conversion
An existing detached or attached garage reframed and finished as a residence. Often the shortest path to a permitted unit, provided the existing structure has the bones to carry the conversion.
04 —
Private studio · Detached retreat
A standalone ADU built primarily as a workshop, gallery, or private studio is the architecturally considered version of the backyard retreat. Fully permitted with kitchen, bath, and sleeping accommodation, which preserves long-term flexibility for guests or rental.
iii. A Closer Look
The private studio. A retreat.
A particular kind of ADU has become a recurring brief in Castle Rock and Douglas County: a detached building that serves as a workshop, a music room, a gallery, a wine room, a golf simulator, or simply a private retreat away from the main residence.
Because the Private Studio is built and permitted as a full ADU, the same building serves as a workshop today, a guest suite during the holidays, and an income-producing rental in retirement. The cost premium over a glorified shed is recovered in resale value, permit standing, and useful life.
A short conversation. Often the right place to begin.
If you are considering an ADU in Castle Rock or the surrounding Douglas County communities, the first step is a thirty-minute conversation. No deck. No pitch.
