MHIC #117311 · Maryland Service Area
Home Additions in Maryland
Maryland zoning, setbacks, stormwater, and historic-district rules make additions complex. We've added bump-outs in Bethesda, second stories in Towson, in-law suites in Columbia, and sunrooms in Annapolis since 2005. One licensed team. One contract.
Pricing
Home Additions cost in Maryland (2026)
| Scope | Investment range | Includes |
|---|---|---|
| Bump-out (≤120 sq ft) | $30,000 – $70,000 | Cantilever or foundation extension. Common for bath, breakfast nook, mudroom. |
| Single-story room addition | $80,000 – $180,000 | 200–400 sq ft new family room, bedroom, or sunroom on existing foundation. |
| Second-story addition | $150,000 – $300,000 | New floor over existing structure. Requires temporary roof, structural review. |
| In-law suite / ADU | $120,000 – $250,000 | Self-contained living area: bedroom, bath, kitchenette, separate entry. |
| Primary-suite addition | $120,000 – $220,000 | Bedroom + walk-in closet + spa bath, often on rear elevation. |
Ranges reflect Maryland market conditions for 2026. Final price depends on county labor rates, fixture grade, and structural complexity. Free fixed-price quote after one in-home visit.
Process
How an Eagle Home Improvements home additions project unfolds
- 01
Feasibility
Setback check, easement review, historic-district verification, structural assessment.
- 02
Design + zoning
Architectural drawings, county zoning approval, HOA review where applicable.
- 03
Engineering
Structural engineer for foundation, framing, beam, and load calculations.
- 04
Permit
Building, electrical, plumbing, mechanical permits — all filed in your county.
- 05
Build
Foundation, framing, roofing, mechanical, drywall, finish — sequenced to keep your home livable.
- 06
Inspection + close
Final county inspection, certificate of occupancy if required, signed 5-year warranty.
Materials we use
Trusted brands across every home additions project
- LP SmartSide / James Hardie siding
- GAF / CertainTeed roofing
- Andersen / Marvin windows
- Trex composite decking
- Code-compliant insulation (R-49 roof, R-21 walls in MD climate zone 4)
Permits & code
Maryland permits we handle
Every Maryland addition requires a building permit, plus separate electrical, plumbing, and mechanical permits. Setbacks, easements, FAR (floor area ratio), and stormwater management vary by county. We handle the entire submittal cycle.
Verify our credentials: MD MHIC License Lookup · MD Home Improvement Commission
Warranty
5-year workmanship
5-year workmanship + full structural warranty on framing, foundation, and roof.
Sub-services for home additions
Every home additions sub-service we offer in Maryland
Eagle Home Improvements handles every variation of home additions — from quick refreshes to full custom builds. MD-specific notes flag county code, climate, or market considerations for each.
Bump-out addition (≤120 sq ft)
Cantilever or foundation extension for breakfast nook, bath expansion, or mudroom.
MD note: No setback issues since under threshold in most MD jurisdictions. Permit-light path.
Single-story room addition
200-400 sq ft new family room, bedroom, or sunroom on existing or new foundation.
MD note: Triggers stormwater management review in Montgomery + Howard County. We handle SWM filing.
Second-story addition over slab ranch
New full second floor over existing slab-foundation rancher. Requires structural review.
MD note: Common in 1950s MD ranches. Foundation reinforcement adds $20K-$45K to scope.
Primary suite addition
Bedroom + walk-in closet + ensuite bath added to existing footprint, typically rear elevation.
MD note: Most-requested addition type in Bethesda, Potomac. 12-16 week typical timeline.
In-law suite / accessory dwelling unit (ADU)
Self-contained living area with bedroom, bath, kitchenette, separate entry.
MD note: Maryland counties allow ADUs in most residential zones. Howard + Anne Arundel counties have streamlined ADU permits.
Sunroom / four-season porch
Climate-controlled glassed-in living space with HVAC integration.
MD note: Trex Transcend or Andersen 100 Series glazing for MD freeze-thaw cycles. Year-round usable.
Detached garage with bonus room
New garage with finished bonus room above — office, gym, or guest space.
MD note: Setback rules vary by Maryland county — Montgomery and Howard treat detached differently than Anne Arundel or Baltimore County. We file the appropriate permit.
Second-story master deck or balcony
Second-level outdoor space accessed from primary suite or family room.
MD note: Code-compliant railings (36"+ height, 4" baluster max). Common in Annapolis bay-view homes.
Maintenance — keep it perfect
How to maintain your home additions in Maryland
MD climate (humid summers, freeze-thaw winters, high pollen) is harder on finishes than coastal CA or arid SW. These tips extend the life of your investment by years.
- Annual (spring)
Inspect addition flashing + tie-in seams annually
Visual inspection of where new addition meets existing structure — siding seams, roof tie-in, foundation joint. Look for caulk failure.
- Twice yearly
Clean gutters on new addition + verify pitch
New gutters can sag if undersized for roof area. Check for proper pitch toward downspouts.
- Annual
Inspect new HVAC ductwork connections
Verify ducts to new addition rooms aren't leaking conditioned air. Mastic-seal any visible gaps.
- Annual + after major storms
Check stormwater management dry well or detention area
Required by MD county permits. Verify dry well isn't collapsed and water flows to it after heavy rain.
- Year 2 then every 5 years
Re-caulk window perimeter on new addition
New construction settles in first 12-24 months. Re-caulk window/door perimeters at year 2.
- Annual
Inspect foundation perimeter for settling cracks
Hairline cracks normal; cracks wider than 1/8" or stair-step pattern in masonry need investigation.
FAQ
Frequently asked questions about home additions in Maryland
How much does a home addition cost in Maryland?
Most Maryland additions cost $80,000–$250,000 in 2026. Per square foot, expect $250–$500 depending on scope, finish level, and structural complexity.
Can I add a second story to my Maryland home?
Often yes — but it requires structural review of the existing foundation and walls. A ranch with a slab may need foundation reinforcement; a colonial with full basement is usually feasible without that step.
Will my home be livable during construction?
Usually yes. We seal off construction areas with ZipWall, run separate HVAC, and stage utility shutoffs. Brief disruption (2–5 days) for tie-ins is typical.
How do I know if my lot can support an addition?
Setback, easement, and FAR limits dictate buildable area. We pull your plat and county zoning record during the free consultation and tell you what is feasible.
Do additions require an architect?
Maryland counties accept design-build engineered drawings for most additions. Larger or historic-district projects may require a registered architect — we coordinate when needed.
What about HOA approval?
Many MD subdivisions require HOA architectural review. We prepare board-ready submittal packages including elevations, materials, and color samples.
How long is the permit process?
Typical permit cycle is 4–10 weeks depending on county. Montgomery and Howard run longer; Baltimore County and Anne Arundel run faster.
Do you handle the design + build under one contract?
Yes — design-build is our model. One team. One contract. One fixed price after design is signed off.
Other services
One MHIC-licensed team for every Maryland remodel
- Bathroom Remodeling
- Kitchen Remodeling
- Basement Finishing
- Whole-Home Renovation
- Flooring Services
- Painting Services
- Drywall Repair & Installation
Top service areas
Home Additions across Maryland
Free In-Home Consultation
Ready for your home additions in Maryland?
Free in-home estimate, fixed-price quote within 48 hours. MHIC #117311 · $2M general liability.