ADDITIONS AND ALTERATIONS
When is a Building Permit Required?
If you are building, installing, and/or altering any of the following you may need a building permit:
- Addition
- Basement-existing
- Deck
- Driveway (apron only)
- Electrical Work
- Exterior Work on Historic Property
- Fence
- Fire Repair
- Garage
- Hot tub
- HVAC/Heating (replacing)
- Interior Alteration
- Retaining Wall
- Replacing structural members of roof framing, including sheathing
- Solar Panels
- Shed
- Signs
- Sunroom
- Swimming Pool
- A wood burning stove/fireplace installation
- Change the size of doors and windows or make new openings for same
- Change a building's use
- Structural alterations
PLAN SUBMITTAL GUIDELINES
These guidelines contain a list of plan details, specifications, and technical information generally
required for plan review for additions/alterations to single-family dwellings (attached or
detached). This list is not all-inclusive and detailed, and further information may be required if
needed at the time of plan review. When the proposed construction is not conforming to the
residential building code or when the project is unusual or complex, DPS may require and accept
such certification from a Maryland Registered Architect or Professional Engineer. The design
must be in accordance with accepted engineering practice.
A. General requirements:
1. Two complete sets of plans, including site plans, assembled in a logical sequence and bound
neatly.
2. Plans and documents must be suitable for electronic scanning (no dark background, no faint
copies, no blurred lines or lettering, no lined paper, or graph paper.)
3. Clouds, if used, must be identified and dated.
4. Plans that are pieced/taped together will not be accepted.
5. Provide door and window schedule(s) with size, glazing type (tempered, for example), and Uvalue.
6. Provide location of smoke detectors.
7. Copy of the Maryland Department of Assessments and Taxation, Real Property Data Search,
showing the property land area
B. Zoning requirements:
For building permits without Maryland National Capital Park and Planning Commission
(MNCPPC) site plan approval, click here for 2-story and 2nd story additions or click here one
story addition. For building permits with MNCPPC site plan approval, call 311.
C. Drainage Plans, engineering scale 1” to 10 feet (2 Copies Required):
1. All property lines, lot dimensions, lot area, widths of easements, and rights of way
2. Location of all existing and proposed buildings and structures, driveways, sidewalks,
drainage devices, drainage ditches, swales, culverts, curb and gutter, patios, decks and
any other impervious surfaces
3. Area of existing and proposed impervious surfaces mentioned in items 1 and 2.
4. Elevations at the corners and halfway between the corners of the existing and
proposed house or addition, corresponding front-, side-, and backyard-yard midpoints,
and corresponding lot lines points. NOTE – Additional topographic info may be required as
deemed necessary
5. Elevations of the lower floor, basement floor slab, garage floor slab, and impervious
surfaces for existing and proposed buildings
6. Location and elevation of roof downspouts for existing and proposed buildings
7. Directional arrows to show the existing and proposed drainage pattern.
For example, show downspout flows and sheet flows that are conveyed off the lot or
collected to an on-site device or facility
8. Size, material, length and class of drainage pipes within the existing and
proposed collection system, and the elevation of the bottom of the pipe at discharge points
9. If fill is added on the lot, the grades on neighboring properties must be shown
for the existing and proposed buildings. Site grading shall not obstruct existing drainage
from adjacent properties
10. Plans prepared by an engineer, surveyor or architect licensed in Maryland,
include his/her seal, date and signature.
D. Architectural/structural plan (two sets) drawn to scale and dimensioned:
1. Architectural floor plans - one plan for each floor (Scale: 1/8” = 1’, preferred 1/4”=1’)
a. Label floor plan(s) of existing building (basement, first story, etc.) affected by the
addition/alteration, including dimensions, use of each space, stairways, doors, windows,
construction materials, means of egress, etc.
b. Label floor plan(s) of proposed addition/alteration including dimensions, use of space,
stairways, doors, windows, construction materials, means of egress, etc.
c. Provide the gross square feet of new space (basement, each floor, and attic).
d. Provide location of smoke and carbon monoxide alarms
2. Foundation plan and structural framing plan – one structural plan for each floor (Scale: 1/4” =
1’)
a. Show existing footing/foundation and floor/roof structural framing affected by the
addition/alteration. Indicate location, size, spacing, and material of all structural and
framing elements (sheathing, rafters, trusses, joists, beams, posts, bearing walls,
foundation walls, footings, etc.).
b. Show footing/foundation and floor/roof structural (line drawing) framing of proposed
addition/alteration. Indicate location, size, spacing, and material of all structural and
framing elements (sheathing, rafters, trusses, joists, beams, posts, bearing walls,
foundation walls, footings, etc.), and soil data, if necessary, such as type of soil and
bearing capacity.
c. When using wood trusses, provide truss design drawings showing depth, span, spacing,
bearing widths, design loads, and connections on framing plans.
d. Provide a steel lintel schedule, if any, for the support of the brick veneer.
e. Wall bracing details - indicate method(s) of wall bracing as specified in Chapter 6 of IRC
2009, provide braced wall panel layout specifying amount of bracing, location of braced
wall lines and braced wall panels on each story, panel length, connection details.
3. Elevations of existing building and proposed addition (Scale: 1/4” =1’)
a. Show doors, windows, other exterior openings, exterior structural elements, gables,
dormers, stairways, chimneys, other exterior architectural features/details, and exterior
finish materials.
b. Show exterior proposed grade, roof pitch, and vertical dimensions of all construction
elements and architectural features.
c. Show crawl space, if any, including elevations and vents
d. Indicate braced wall lines and braced wall panels.
4. Cross-sections (Scale: 1/4” = 1’)
a. Show existing and proposed work affected by the addition/alteration
b. Show vertical dimensions of all significant construction elements (ceiling heights,
duct/beam clearances, door/window openings, headroom, door/window heights, sill
heights, etc.)
c. Show size, spacing, and material of all structural elements (footings, foundation walls,
bearing walls, posts, beams, joists, rafters, trusses, sheathing, etc.)
d. Show special areas/features (stairs, fireplace/chimney, etc.)
e. At least one complete section showing the thermal envelope
5. Details (Scale: 1/2” = 1’)
a. Show footings, retaining walls, unusual structural arrangements and/or connections,
indicating materials and size, type, location, and spacing of reinforcing, connectors, etc.
b. Show stairway construction (including spiral/circular) indicating materials and
dimensions of all treads, risers, landings, winders, guards, handrails, headroom, etc.
E. Technical information required:
1. Specifications
a. Design criteria as required by the International Residential Code (IRC) 2009 as amended
by Montgomery County for: floor load, roof load, ground snow load, wind loads, seismic
design category, frost line depth, decay protection measures, flood-resistant construction
provisions, if any, click here for criteria.
b. Species/grades of framing lumber;
c. Grades/classes of other structural elements; and
d. Grades/types of construction materials and finishes
2. Engineering data/computations required to complete plan review
3. The plan reviewer may require that the structural aspects of the construction documents be
signed and sealed by a Maryland Registered Architect or Professional Engineer. The design
must be in accordance with accepted engineering practice.
F. Energy efficiency requirements:
1. Energy conservation plans, analysis/computations based on the International Energy
Conservation Code 2009. Click here for further requirements
NOTE: Properties that lie within incorporated areas typically require building permits from the
municipality in addition to Montgomery County Department of Permitting Services (DPS), see
Permit Procedures for Properties Within a Montgomery County Municipality document
issued by DPS.
Failure to comply with these guidelines may result in your plan(s) not being accepted for review.
Other Permits
In many circumstances, electrical, mechanical, fire alarm, sediment control, public right of way , well, septic and/or fire protection permits are required to complete the project.
How can I Accelerate my Review Process?