ADU Construction in Kensington, MD — Accessory Dwelling Unit Contractor
Types of ADUs We Build in Kensington, MD
Kensington's smaller lot sizes and historic housing stock make some ADU types more feasible than others. Here is a realistic assessment of the ADU types that work in Kensington — with cost ranges for this market:
Basement ADU Conversion
Converting an existing basement to a legal rental unit is the most practical ADU path for most Kensington properties — it adds no new building footprint, avoids setback constraints entirely, and uses existing structure. Kensington's Victorian and Craftsman basements have specific considerations (ceiling height, stone foundations, older systems) that DMV-GC Group assesses honestly before any design begins. Includes egress windows, separate entrance, kitchen, bathroom, fire separation, and Montgomery County COO.
Garage Conversion ADU
Many of Kensington's Victorian and Craftsman homes have detached garages — built in the 1920s–1940s, separate from the main house — that are strong ADU conversion candidates. Where the garage has sufficient square footage (typically 300+ sq ft) and ceiling height (7'+), conversion to a studio or one-bedroom ADU is feasible. Includes insulation, HVAC, plumbing, egress, interior framing, kitchen, and bathroom. Town permit and COO required.
Attached In-Law Suite Addition
A new addition built onto the side or rear of the main home — separate entrance, bedroom, bathroom, and kitchen or kitchenette. Feasible on Kensington's larger lots where setback requirements can be met. Architecturally designed to be compatible with the Victorian or Craftsman character of the existing home — essential for both aesthetic and town permit approval. Includes full structural design and Town of Kensington permits.
Detached ADU — Backyard Cottage
New construction of a standalone structure in the rear yard. Less common in Kensington than in Potomac or Bethesda due to smaller lot sizes — but feasible on Kensington's larger parcels that exceed the 6,000 sq ft minimum with enough room for a detached structure after meeting setback requirements. Where feasible, a detached ADU maximizes privacy and rental income potential.
ADU Construction in Kensington's Historic Homes — What's Different
Building an ADU in a Kensington Victorian or Craftsman home is not the same as building one in a 1990s colonial or a newer suburb. The specific characteristics of Kensington's older housing stock create real-world constraints and considerations that need to be assessed honestly before any ADU project is designed or priced.
📏 Basement Ceiling Height
Victorian and Craftsman basements in Kensington frequently have ceiling heights of 6'4"–7'2" — at or just above the 7-foot minimum required for habitable ADU space. This is the most common constraint in Kensington basement ADU projects. DMV-GC Group measures every square foot of ceiling height and identifies where HVAC rerouting can recover clearance before any ADU floor plan is designed. Areas that don't meet the minimum cannot be counted as habitable ADU space.
💧 Stone & Block Foundation Moisture
Kensington's oldest homes have rubble stone or early block foundation walls that manage moisture differently than modern poured concrete. A basement ADU in a home with an unaddressed moisture history will develop moisture problems after it's rented — and fixing them requires removing finished work. DMV-GC Group's moisture assessment is a required first step before any basement ADU design is finalized. The assessment is in writing, honest, and free.
🔧 Older Plumbing & Electrical
Homes built before 1950 in Kensington often have galvanized steel supply lines and older electrical systems. For a basement ADU where a tenant will rely on water pressure and electrical capacity, these systems must be assessed and — where degraded — updated before the ADU is occupied. DMV-GC Group's licensed plumbers and electricians assess all systems in the ADU zone during the initial consultation.
🏘️ Lot Size Constraints
Kensington's historic lots tend to be smaller than most Montgomery County communities — many between 6,000 and 9,000 sq ft. This directly affects ADU feasibility: detached ADUs require enough rear yard area to meet setback requirements while leaving the ADU footprint. On smaller Kensington lots, basement and garage conversion ADUs are typically the most practical path. DMV-GC Group confirms ADU feasibility for your specific lot before any design work begins.
Town of Kensington ADU Permit Process
Kensington's incorporation as a town within Montgomery County creates a permit jurisdiction that many contractors mishandle. All construction within the Town of Kensington's limits — including ADU projects — requires permits from the Town of Kensington, not from Montgomery County DPS. Filing with the wrong authority is one of the most common and costly contractor mistakes in Kensington ADU projects.
📋 Town of Kensington ADU Permit Process — What to Expect
- Issuing authority: Town of Kensington Town Hall. All building, electrical, and plumbing permits for ADU projects within the town limits are issued by the Town — not by Montgomery County DPS.
- Zoning compliance: Kensington properties must comply with Montgomery County's ADU ordinance (which governs the zoning rules — lot size minimum, ADU size limits, setbacks) even though building permits are issued by the Town. DMV-GC Group verifies compliance with both the county's zoning ordinance and the Town's building permit requirements before filing anything.
- Plan review: The Town reviews submitted drawings before issuing ADU permits. Plans must show the proposed floor plan, egress window locations, separate entrance design, kitchen and bathroom layout, electrical layout, and any structural work. DMV-GC Group prepares all required drawings in-house.
- Architectural compatibility: For attached additions and garage conversions that modify the exterior of a historic Kensington home, the Town's review may consider whether the proposed design is compatible with the character of the existing structure. DMV-GC Group designs all Kensington ADU additions to be architecturally compatible with Victorian and Craftsman aesthetics.
- Certificate of Occupancy: A COO is required before the ADU can be legally occupied or rented. DMV-GC Group manages the COO application and all required inspections through the Town of Kensington process.
- Properties outside town limits: A small number of Kensington-mailing-address properties fall outside the incorporated town limits — in unincorporated Montgomery County. These properties require Montgomery County DPS permits rather than Town permits. DMV-GC Group verifies the exact jurisdiction for every Kensington address using parcel boundary data before filing anything.
Benefits of Building an ADU in Kensington
Kensington's MARC rail connection (Kensington station on the Brunswick Line), proximity to Silver Spring and Bethesda, and desirable community character create solid rental demand for quality ADU units. Here is why Kensington homeowners are investing in ADUs:
Kensington Detached Garage Conversions — What Makes Them Work
Kensington's Victorian and Craftsman homes frequently have detached garages built in the 1920s–1940s — separate structures behind the house, originally designed for car storage in an era when cars were new. Many of these garages have been used for storage for decades and have never been seriously evaluated as ADU candidates. Here is what makes a Kensington garage a strong — or weak — ADU conversion candidate:
🚗 Kensington Detached Garage — ADU Feasibility Assessment
- Minimum square footage: A functional studio ADU requires approximately 300–350 sq ft of livable space — enough for a sleeping area, bathroom, and kitchenette. A one-bedroom ADU requires 450–550+ sq ft. Kensington's older single-car garages (typically 12'x20' = 240 sq ft) may be too small for a code-compliant ADU without expansion. Two-car garages (typically 20'x20' = 400 sq ft) are often a better candidate.
- Ceiling height: The finished ceiling height of the ADU must meet the 7-foot minimum for habitable space. Older garages with low-pitched roofs may have insufficient interior height for a standard finished ceiling — especially after adding insulation and drywall to the ceiling. DMV-GC Group measures the existing interior height during every garage assessment.
- Foundation condition: Older Kensington garages are often built on a concrete slab with no formal foundation — or on rubble stone piers. The slab condition (cracks, settlement, moisture) must be assessed before any interior finishing. Plumbing for a bathroom requires cutting through the slab for drain installation.
- Structural condition: Garages from the 1920s–1940s used wood framing that may have deteriorated where it contacts grade — sill plates, bottom plates, and wall sheathing near the ground. A structural assessment before conversion planning is essential for any garage of this age.
- Utility connections: Electrical service to the garage (if present) must be evaluated for capacity — a dedicated sub-panel is required for an ADU. Water and sewer connections to the garage are rarely present and must be run from the main house — the distance affects cost significantly.
- Town of Kensington setbacks: The existing garage must meet the Town of Kensington's setback requirements for an ADU use — or a variance may be needed if the structure is non-conforming. DMV-GC Group confirms setback compliance for every Kensington garage before any conversion is designed.
Our ADU Construction Process in Kensington
Free In-Home Consultation & Feasibility Assessment
We visit your Kensington home and assess all ADU options honestly — basement ceiling heights and moisture conditions, garage dimensions and structural condition, lot size and setback room for addition or detached ADU. We tell you which ADU types are genuinely feasible on your specific property and provide a realistic preliminary budget range. No cost, no obligation.
Jurisdiction Verification
We verify whether your Kensington address falls within the incorporated Town of Kensington limits or in unincorporated Montgomery County — confirming which permit authority governs your project before any design or application begins. This verification uses parcel boundary data, not mailing address assumption.
Systems Assessment & Pre-ADU Remediation Plan
For basement ADU projects: written moisture assessment and older systems evaluation (plumbing, electrical). For garage conversions: structural assessment of framing, slab, and sill plate condition. Any required remediation — galvanized plumbing replacement, electrical upgrade, moisture management — is designed and priced before ADU design begins.
ADU Design Development
Our design team develops a floor plan, egress window layout, separate entrance design, kitchen, and bathroom configuration — all within the actual constraints confirmed during the assessment phase. For attached additions and garage conversions, exterior design is developed to be compatible with the Victorian or Craftsman character of the existing home.
Town of Kensington Permit Filing
We prepare all required drawings and file all applications with the Town of Kensington — building, electrical, and plumbing permits. Our permit team manages all Town correspondence, plan review responses, and inspection scheduling throughout the project.
Construction — Systems, Structure & Finishes
Pre-ADU remediation (moisture management, plumbing, electrical) is completed first. Then structural work (framing, egress windows, separate entrance), followed by mechanical rough-ins, insulation, drywall, flooring, kitchen, bathroom, and all finish work — coordinated by a dedicated project manager throughout.
Town Inspections, COO & 1-Year Warranty
We manage all required Town of Kensington inspections and the Certificate of Occupancy process. After COO issuance, we conduct a final walkthrough, address every punch list item, and activate your 1-year workmanship warranty.
ADU Construction Cost in Kensington, MD
Here is a realistic cost breakdown for ADU construction in Kensington, Maryland. Costs for older historic homes typically run 10–20% higher than comparable projects in newer construction — reflecting additional systems work and moisture management requirements:
| ADU Type | Typical Cost Range | Notes for Kensington |
|---|---|---|
| Basement ADU Conversion | $75,000 – $130,000 | Includes moisture management, egress windows, separate entrance, kitchen, bathroom, fire separation, COO. Older homes may add 10–15% for systems remediation. |
| Garage Conversion ADU (existing structure) | $65,000 – $120,000 | Older garages may require sill plate replacement, structural reinforcement, and longer utility runs from main house — all assessed during consultation. |
| Garage Conversion + Small Addition | $90,000 – $150,000 | Where the existing garage is slightly undersized, a small bump-out addition can bring it to ADU-viable square footage. |
| Attached In-Law Suite Addition | $110,000 – $220,000 | New addition with separate entrance, bedroom, bathroom, and kitchen. Architectural compatibility with Victorian/Craftsman character required. |
| Detached ADU — Backyard Cottage (where feasible) | $140,000 – $280,000 | New construction. Feasibility depends on lot size and setback room. Less common in Kensington than in larger-lot communities. |
| Pre-ADU Systems Remediation (if needed) | $5,000 – $25,000 | Galvanized plumbing replacement, electrical panel upgrade, moisture management — assessed and priced separately before ADU construction begins. |
What Kensington Homeowners Say About DMV-GC Group
"We converted our 1920s detached garage into a one-bedroom ADU — DMV-GC Group found structural issues with the original framing during their assessment and addressed them before any finish work started. The Town of Kensington permits were handled entirely by their team. We're renting it for $1,650/month."
"The basement ADU in our 1910 Victorian was complicated — stone foundation, low ceiling in parts, galvanized pipes. DMV-GC Group assessed all of it upfront, gave us honest numbers for the remediation, and then delivered a beautiful basement apartment. The MARC commuters who've rented it love the walkability."
"Two other contractors didn't know that Kensington has its own permit process separate from Montgomery County. DMV-GC Group knew immediately, filed correctly with the Town, and our ADU project was inspected and got its COO without a single problem. That expertise made all the difference."
"We wanted an in-law suite addition for my mother-in-law. DMV-GC Group designed it to match our Craftsman home's exterior — same siding, same window trim detail, same roof pitch. The Town reviewer actually complimented the design during the permit review. Mom moved in six months after we started."
⭐ 4.9-star rated with 97+ verified reviews. Kensington homeowners trust DMV-GC Group for ADU projects that navigate the Town's permit process correctly, address the real-world constraints of historic home construction honestly, and deliver quality that suits the character of this community.
Serving Kensington and Surrounding Areas for ADU Construction
Also serving Garrett Park, MD — Kensington's neighboring historic town
DMV-GC Group builds ADUs throughout Garrett Park, which borders Kensington to the north and shares the same concentration of Victorian and Craftsman homes with similar ADU construction considerations — including Garrett Park's own Town permit process. View our full ADU construction service page →