When Is a Permit Required?
In Montgomery County, a building permit is required for any deck that is attached to the house, any deck over 30 inches above grade, or any deck larger than 200 square feet. In practice, this means nearly all decks in Rockville require a permit. Unpermitted decks create problems at resale — buyers' inspectors flag them, and you may be required to obtain a retroactive permit or remove the structure.
What the Review Process Looks Like
Montgomery County currently reviews residential deck permits in approximately 4–8 weeks. You'll need a site plan showing the deck footprint, setbacks from property lines, and existing structure. You'll also need a construction plan showing framing, ledger attachment, footing size, and railing details. Elias General Construction prepares and submits all permit documents as part of the project.
The Ledger Attachment Issue
The most common plan review correction for decks in Montgomery County involves the ledger board — the connection between the deck frame and the house. Older homes in Rockville often have hardboard or stucco siding that requires flashing and standoff hardware to create a proper water-managed attachment. We document this in the permit drawings before submission to avoid back-and-forth with the reviewer.
“The permit process took about six weeks. Elias handled every step — we just approved the drawings. When the inspector came, everything passed on the first visit. — Janet H., Twinbrook”
Final Inspection
All permitted decks require a final inspection by a Montgomery County building inspector. We schedule and manage that inspection, and we don't consider a project complete until you have your final approval in hand.