What are the Massachusetts Building regulations for outside decks?

The Massachusetts State Building Code (780 CMR) regulates the design and construction of exterior decks. Some key regulations include:

Deck Height

The maximum height of a deck above the ground is generally 30 inches. However, decks attached to a dwelling unit may be up to 48 inches high.

Deck Area

The maximum area of a deck is generally 200 square feet. However, decks attached to a dwelling unit may be up to 400 square feet in area.

Deck Supports

Deck supports must be designed to carry the weight of the deck and any occupants or objects on it. Supports must be spaced no more than 16 inches on center.

Deck Joists

Deck joists must be made of a solid, durable material. Joists must be spaced no more than 16 inches on center.

Deck Planks

Deck planks must be made of a solid, durable material that is resistant to rot and decay. Planks must be at least 5/4 inches thick and spaced no more than 1/4 inch apart.

Deck Railings

Decks that are more than 30 inches above the ground must have railings that are at least 36 inches high. Railings must be constructed of solid material and have a minimum of one intermediate rail between the top rail and the deck surface.

Deck Stairs

Decks that are more than 24 inches above the ground must have stairs that are at least 36 inches wide. Stairs must have a uniform rise and run, and the maximum rise per step is 7 inches. Stairs must also have handrails that are at least 36 inches high.

Deck Inspections

Decks must be inspected by a qualified inspector before they are used. Decks that are not properly constructed or maintained may be dangerous.

These are just some of the key regulations for decks in Massachusetts. For more information, refer to the Massachusetts State Building Code (780 CMR).