Do I Need a Permit to Build a Deck in Maryland?

Maryland's statewide building code

Maryland takes a structured approach to building codes. The state's law governing construction standards is called the Maryland Building Performance Standards (MBPS), which requires every jurisdiction in the state to use the same edition of the same building codes. The current baseline is the 2018 International Residential Code (IRC) and the 2018 International Building Code (IBC), both with Maryland-specific modifications.

The Maryland Department of Housing and Community Development serves as the statewide adopting authority. When the state updates to a new code edition, every local jurisdiction must adopt it. Local governments can amend the codes to address regional conditions — but they cannot make them less strict than the state standard.

This is a meaningful difference from states like Missouri or Texas, where building codes are purely local. In Maryland, there's a guaranteed floor: no matter which county you're in, the MBPS applies, and the IRC is the basis for residential construction standards.

Permitting, plan review, and inspections are handled at the county level through each county's Department of Permitting Services (DPS). Maryland's counties are the primary enforcement jurisdictions — not cities. This is different from many other states where cities run their own building departments. In Maryland, whether you're in a city like Rockville or Gaithersburg or in an unincorporated area, your deck permit comes from the county.

Deck permit requirements vary significantly across the country — see our national deck permit guide for how Maryland compares to other states.

When you need a permit

Maryland is one of the stricter states when it comes to deck permits. In most counties, a building permit is required for all decks supported by footings, regardless of height above grade. This means that even a ground-level deck that wouldn't need a permit in many other states requires one in Maryland.

Montgomery County's Department of Permitting Services states this explicitly: a building permit is required for all decks regardless of the height above grade. This applies whether the deck is attached to the house or freestanding, whether it's 6 inches off the ground or 6 feet.

Baltimore follows a similar approach — both Baltimore City and Baltimore County require deck permits, though they operate as separate jurisdictions with their own building departments. Baltimore County's Department of Permits, Approvals, and Inspections handles deck permits, while Baltimore City runs its own system through its Department of Housing.

The one exception you may encounter is minor maintenance work. Replacing deck boards without structural changes may not require a permit in some jurisdictions, but any work involving footings, framing, or structural modifications does.

County-based permitting: how it works

Maryland's county-based system means that your experience getting a deck permit depends heavily on which county you're in. The major counties each have well-developed online permitting systems.

Montgomery County offers a Residential Fast Track process for straightforward deck projects that can result in a permit in as little as a few hours. The county provides standardized Residential Deck Details — pre-approved construction templates for single-span, single-level decks that can be used in place of custom construction plans. If your deck fits one of these templates, the review process is significantly faster. Decks with roofs, screened porches, hot tubs, or other additional loads don't qualify for the template approach and need custom plans.

Baltimore County processes deck permits through its online portal. The county provides fillable deck plan templates and detailed construction guidelines. For decks under 3,000 square feet, signed and sealed plans from a design professional are not required — a clear, accurate drawing with dimensions, materials, and structural details is acceptable. Review time is typically 10–15 business days if the application is complete and code-compliant.

Prince George's County has one notable requirement that differs from many other jurisdictions: decks must be self-supporting and freestanding — they cannot rely on attachment to the house for structural support. This means no ledger board connection in Prince George's County. All deck loads must be carried by posts bearing on footings. This adds posts and footings compared to a ledger-supported design.

The MHIC requirement

Maryland requires that all home improvement contractors hold a Maryland Home Improvement Commission (MHIC) license. This is a state-level requirement, not a local one, and it applies to anyone performing contracting work on residential property — including deck construction.

If you hire a contractor to build your deck, they must have a valid MHIC license. The DPS in your county will verify contractor licensing as part of the permit application process. Homeowners can pull their own permits for work they'll perform themselves, but if a contractor is doing the work, the county strongly recommends (and in practice requires) that the contractor be listed on the permit.

The MHIC license requirement provides a layer of consumer protection that doesn't exist in states without statewide contractor licensing. If a dispute arises with your contractor, the MHIC provides a complaint and mediation process.

Frost depth and Chesapeake Bay considerations

Maryland's frost depth varies by region but is generally 30 inches across most of the state. This is the standard minimum depth for deck footings in major counties like Montgomery, Baltimore, Prince George's, and Frederick. Counties on the Eastern Shore or in southern Maryland (like Calvert County) may specify shallower depths — as little as 24 inches — due to milder winter conditions.

The frost depth requirement means footing holes in Maryland are about 2.5 feet deep, which is moderate compared to northern states like Wisconsin (48 inches) but deeper than southern states like Tennessee (12 inches). Each county specifies its own frost depth based on local climate data, so confirm the exact number with your building department.

Maryland's proximity to the Chesapeake Bay and its tributaries adds environmental considerations in some areas. Properties in the Critical Area — defined as land within 1,000 feet of tidal waters or tidal wetlands — face additional review requirements for any construction, including decks. If your property falls within the Critical Area, expect additional environmental review as part of the permit process.

Flood zone considerations also apply to waterfront or low-lying properties. If your property is in a FEMA-designated flood zone, your deck may need to comply with floodplain management regulations, which can affect the allowed height and foundation design.

What you need to submit

A typical Maryland deck permit application requires:

• A completed building permit application (submitted electronically through your county's DPS portal in most counties)
• A site plan showing property boundaries, existing structures, the proposed deck location, distances to property lines, and easements
• Construction plans showing deck dimensions, framing layout, materials, footing details, railing specifications, and stair details
• If applicable, an electrical permit (for stairway lighting, hot tubs, or outlets)
• MHIC contractor license information (if using a contractor)

Montgomery County and Baltimore County both offer standardized deck drawing templates that homeowners can use for simple projects. These templates are pre-approved for code compliance — you fill in your specific dimensions and materials, and the plan review process is streamlined.

For Rockville, Gaithersburg, and other municipalities within Montgomery County, the county DPS handles the building permit. However, some Montgomery County municipalities require additional local approvals.

Annapolis adds a layer of complexity for properties in the city's historic district. The Historic Preservation Commission may require design review for exterior construction, including decks, to ensure compatibility with the district's character.

Inspections and completion

Maryland counties require multiple inspections during deck construction. The typical sequence is:

• Footing inspection — after excavation and before concrete is poured, verifying depth, diameter, and soil conditions
• Framing inspection — after structural framing is complete, checking joist size and spacing, beam connections, post attachments, and ledger board installation (where applicable)
• Final inspection — after all work is complete, verifying guardrail height and spacing, stair dimensions, structural connections, and overall code compliance

Baltimore County notes that framing and final inspections can sometimes be combined into a single visit if the deck is at least 48 inches above grade. For decks with electrical work (hot tubs, outlets, stair lighting), additional electrical inspections are required.

Schedule inspections through your county's online portal. Have your permit card posted and your approved plans available on-site for the inspector.

The HOA factor

Maryland has a high concentration of Homeowners Associations (HOAs), particularly in the suburban counties surrounding Baltimore and Washington, D.C. If your property is governed by an HOA, you likely need architectural review approval in addition to your building permit.

HOA requirements are separate from the building code. An HOA may restrict deck materials, colors, railing styles, placement, and size — even if the building code would allow them. The county does not enforce HOA covenants, and HOA approval does not replace the building permit. You need both.

Check with your HOA early in the planning process. Some HOAs take weeks to review applications, and starting construction before receiving HOA approval can result in fines or a requirement to modify or remove the deck.

What happens if you skip the permit

Building a deck without a permit in Maryland is a violation of the building code and can result in fines, a stop-work order, and a requirement to obtain a retroactive permit. Unpermitted work may need to be partially deconstructed so that inspectors can verify hidden elements like footing depth and structural connections.

The consequences extend to property transactions. Maryland real estate transactions routinely involve permit record searches, and unpermitted structures can delay or prevent a sale. You may be required to obtain a retroactive permit and bring the deck up to current code before closing — a process that can be expensive and time-consuming.

For an overview of all building permit requirements in Maryland — including sheds, fences, pools, and more — see our complete Maryland building permit guide.

If you're also planning a fence or patio alongside your deck, note that Maryland has separate permit requirements for each — see our guides to fence permits in Maryland and patio permits in Maryland.