Completed rear home addition on a Denver house, seen from the garden
Denver, Colorado · Design-Build

Denver additions, ADUs and whole-home remodels.

Design-build across Denver’s older neighbourhoods — additions, pop-tops, accessory dwelling units and structural remodels, documented from the excavation through to the final walk.

Denver, Colorado

Denver just made ADUs legal on most of the city. Almost nobody has told homeowners.

In December 2024 a citywide rezoning took effect that lifted the share of Denver land where an accessory dwelling unit is allowed from roughly 36 per cent of the city to about 70 per cent. If you looked into an ADU before that and were told no, the answer has probably changed — and the owner-occupancy requirement that used to make them impractical for a lot of people is gone.

Residential code2025 Denver Building & Fire CodeDenver adopted its 2025 Building and Fire Code — built on the 2024 I-Code base — on 13 June 2025, effective 31 December 2025. Denver writes its own amended code rather than adopting the model code straight, so a set of plans drawn for a neighbouring jurisdiction is not automatically a set of plans that passes in Denver.
Accessory dwelling unitsAllowed on roughly 70% of the cityA citywide ADU rezoning was adopted on 18 November 2024 and took effect 16 December 2024. ADU-eligible land went from about 36% of Denver to about 70%. The owner-occupancy requirement was removed. There is no single citywide size cap — the limit comes from your zone district — and the lot-coverage exemption was extended to cover ADUs, which in practice is what makes many narrow lots work.
Landmark and historic districtsA Certificate of Appropriateness is mandatoryIf your property is a designated landmark or sits anywhere inside a historic district, exterior work, development and demolition all require a Certificate of Appropriateness, and it has to be submitted together with the building and zoning permit rather than afterwards. Denver has a lot more properties inside historic districts than most owners realise. We check this before design, because finding out late reorders the whole schedule.
What this means for your projectThe rules moved recently — in your favourBetween the December 2024 rezoning and the December 2025 code change, most of what a Denver homeowner was told about additions and ADUs before 2025 is now out of date. The practical effect is that more lots can carry a second unit than could two years ago, and the owner-occupancy barrier that used to stop people building one to rent has been removed.

Verified against official City and County of Denver and Colorado Department of Local Affairs sources as of August 2026. Code editions and ADU rules change, and several Front Range jurisdictions are mid-revision right now. Treat this as the starting point for your project, not as legal advice, and confirm the current standard with Denver Community Planning and Development before you commit to a design. We do that on every job as a matter of course.

Built Here

Denver work we documented from demolition to the final walk.

Completed rear home addition elevation on a Denver house

Denver Home Addition, Kitchen & Bath

A rear addition tied into the existing structure, with the kitchen and bathroom rebuilt around the new plan rather than squeezed into the old one.
Denver brick bungalow after a full second-storey pop-top addition with the original brick ground floor retained

Denver Pop-Top, Detached ADU & Whole-Home Remodel

A full second storey framed above the original brick, a two-bedroom ADU over a new detached garage, and the whole house back to the studs — photographed from demolition to the finished elevation.
Straight Answers

Denver questions we get asked.

Can I build an ADU in Denver?

On most of the city now, yes. The citywide ADU rezoning adopted on 18 November 2024 and effective 16 December 2024 raised ADU-eligible land from roughly 36% of Denver to roughly 70%, and removed the owner-occupancy requirement. There is no citywide square-footage cap — your zone district sets the limit — and the lot-coverage exemption now extends to ADUs, which is often what makes a narrow lot work. If you were told no before 2025, it is worth asking again.

Which building code will my Denver plans be drawn to?

The 2025 Denver Building and Fire Code, adopted 13 June 2025 and effective 31 December 2025. It is based on the 2024 I-Codes but Denver amends heavily, so it is not interchangeable with a neighbouring jurisdiction's code. Plans drawn to a generic 2024 IRC set are not automatically Denver-compliant.

My house is in a historic district. What does that add?

A Certificate of Appropriateness. In Denver it is mandatory for exterior work, development or demolition both on designated landmarks and on any property inside a historic district, and it must be submitted alongside the building and zoning permit rather than after. It does not stop a project, but it has to be planned into the schedule from the start, and it shapes exterior material and window decisions.

Tapered columns on stone bases across a completed porch
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