More so than the “what” are the guidelines of installing a deck, is understanding that in New York City, the Department of Buildings (DOB) requires that a deck be permitted and approved prior to being installed. An improperly constructed deck can be dangerous, or can damage your home. Specific structural guidelines must be followed to ensure your deck will be safe for use.

In order to prevent potentially hazardous building practices, local building code lays out a set of standards for deck construction. Although codes vary from locale to locale, many of them are based on the International Residential Code, which sets out requirements in a few key areas of deck design and construction.

Many known guidelines relate to railing height or the space between posts and balusters, however, there are also important guidelines to follow with respect to the decks structure. Footings need to be properly spaced and set below the frost line to ensure they do not shift in frigid temperatures.  Treads and stringers need to be properly spaced, and ledger boards need to be fastened with specifi types o lag screws. Furthermore, NYC code in particular requires that a deck or porch may only project up to eight feet beyond the face of the building.

When a deck has been improperly installed, has been installed without receiving approval by the DOB, or is too close to the property line, it may eventually need to be taken down. This means that you not only paid to have it installed, you will have to pay to take it down. If somehow the Department of Buildings is made aware of your “illegal deck”, an inspector may be sent out to your home to verify the validity of the claim. The inspector can, and in most cases, will issue a violation, creating a lot of red tape and an even greater expense to the homeowner.

Hiring an architect to discuss the type of deck you would like to install is the first step of the process, as a deck, or porch, may only be installed if there is adequate space on your property, as determined by zoning regulations and your property survey.

rchitects can also discuss with you the function and durability of decking materials that are available on the market. This can be helpful as some of the materials used to construct decks require maintenance, and in the long run, can add to the cost of having a deck.

While your architect will review requirements that are specific to your property, there are certain general rules that apply to most porch and deck construction in NYC:

  • There must be at least three feet between the deck or porch and the property line on the sides.

  • All decks and porches must have a railing at least 42 inches high.

  • Spaces between railings and/or posts can be no greater than five inches.

  • Elevated decks and porches must be braced at the columns and where the beams and columns connect.

  • Decks and porches should be able to withstand a minimum of 40 pounds per square foot plus the weight of the deck or porch, so the structural design and materials used are important considerations.

  • Decks and porches must be properly anchored to a house or building and restrictions apply to use of wood material near lot lines and multiple dwellings.

  • No storage is permitted below a deck or porch.

Prior to retaining a contractor, you must verify they have a home improvement contractor’s (HIC) license issued by the NYC Department of Consumer Affairs, and carry the proper insurance, as both are required to secure a permit to begin construction. Your licensed contractor should provide you with a detailed contract indicating the cost and scope of work in accordance with Consumer Affairs guidelines.

Work cannot commence on your porch or deck unless and until a permit is secured. Any plumbing or electrical work included in the scope of the project must be performed by a licensed plumber or electrician, respectively. Homeowners cannot perform plumbing or electrical work themselves.

It is important to note, that regulations from other agencies may apply to your property if it is landmarked, or is situated in a special natural area, historic, or other designated district. These regulations may concern front, rear, or side yard requirements, tree maintenance, and/or grading requirements that would affect your porch, or deck location choice.

Upon completion of construction, sign-off inspections may be required, an updated survey may be needed indicating the conditions as completed, and either a Letter of Completion or amended Certificate of Occupancy may be issued depending upon the type of approval that was required.

The process of installing a deck can be more than you expected, however, when your deck is constructed properly, and when it is record with the Department of Buildings, you peace of mind will be worth the process. When you are ready to sell your home, you will be able to do so without issue, as an illegal deck can halt or kill a house sale.

Contrary to many myths and untruths, all decks and porches must be approved by the NYC Department of Buildings and a permit must be issued for the work to commence.

Jeff Troost, President – Troost Bros Inc.

(718) 667-3131