Home Additions in Washington, DC
Permit Authority for Home Additions in Washington, DC
📋 DLCP Licensed #410526000209
DC Department of Buildings (DC DOB) at 1100 4th Street SW. DC DLCP license #410526000209 required for all DC addition work. HPRB review required for exterior additions visible from the street in DC historic districts. Rear additions on rowhouses generally do not trigger HPRB.
Home Addition Types We Build in Washington, DC
Single Room Addition
A new room built onto the side or rear of your existing home — bedroom, family room, or home office — fully integrated with the existing structure, roofline, and interior layout. Foundation, framing, roofing, electrical, HVAC, and all finishes included.
Second-Story Addition
Add a complete or partial second floor above your existing home — maximizing square footage without expanding the footprint. Full structural engineering required. Adds the most square footage per dollar of lot used.
Master Suite Addition
A dedicated primary bedroom and bathroom addition — one of the most popular additions in Washington, DC. Includes spacious bedroom, walk-in closet, and luxury bathroom. Significant resale value addition.
Bump-Out Addition
A targeted 2–12 foot extension of an existing room — expanding a kitchen, widening a master bath, or creating a breakfast nook. Faster and more affordable than a full room addition.
Family Room Addition
Expand living space with a dedicated family room or great room off the rear of your home — often combined with kitchen expansion. Vaulted ceilings and large windows are the most popular design choices.
Four-Season Sunroom
A light-filled, fully conditioned addition with expansive windows for year-round use. Full HVAC connection, insulated walls, and heated floors. Perfect for rear yards with garden or wooded views.
Home Addition Cost in Washington, DC
| Addition Type | Typical Cost Range | Size | Timeline |
|---|---|---|---|
| Bump-Out Addition | $40,000 – $120,000 | 50–300 sq ft | 2–4 months |
| Sunroom / Four-Season Room | $80,000 – $160,000 | 150–400 sq ft | 3–5 months |
| Single Room Addition | $120,000 – $220,000 | 200–600 sq ft | 4–7 months |
| Family Room Addition | $130,000 – $260,000 | 300–700 sq ft | 4–7 months |
| Master Suite Addition | $150,000 – $300,000+ | 400–800 sq ft | 5–8 months |
| In-Law Suite Addition | $140,000 – $270,000 | 400–800 sq ft | 5–8 months |
| Second-Story Addition | $200,000 – $420,000+ | 600–1,800+ sq ft | 6–11 months |
Our Home Addition Process in Washington, DC
Free In-Home Consultation & Feasibility Review
We visit your Washington, DC home, confirm the correct permit jurisdiction with DC DOB, review zoning and setback requirements, assess the existing structure, and discuss which addition types are feasible — including HPRB considerations for historic district properties — at no cost. Realistic budget range provided before any design work begins.
Architectural Design & 3D Renderings
In-house architects develop concept plans, floor layouts, and 3D renderings refined until they reflect your vision — reviewed by our construction team to ensure buildability within budget. HPRB-submission-ready drawings prepared for historic district properties where required.
Structural Engineering & Permit Submission
In-house structural engineers perform load calculations and specify all structural elements. Complete permit package submitted to DC DOB at 1100 4th Street SW. HPRB review coordinated where required. All permit correspondence managed in-house.
Foundation, Framing & Exterior Construction
Site preparation, footings, foundation, and structural framing completed by our licensed crews. Exterior roofing, siding, and windows installed to match your home's existing exterior materials and profile.
Mechanical Rough-In & Interior Finishes
Licensed electricians, plumbers, and HVAC technicians extend all systems into the addition. Interior finishes installed — matching or upgrading your home's existing standard. All permit inspections managed in-house.
Final Inspections, Punch List & Walkthrough
All required final inspections scheduled and managed. Thorough punch list walkthrough before project close. Written warranty documentation provided.