Posted by Ingrid Spencer in Home Maintenance

Building code basics for turning attic space into living space

You figure you'll need to beef up the floor—insulate and perhaps more. Here's a look at some building-code basics when it comes to turning attic space into living space.

Access and egress

Code generally requires a full-size staircase with a minimum 6-foot 8-inch clearance above it. For fire safety, there must be two ways out—a second staircase, for example, or a window.

Ceiling height

Any living space requires at least 7 feet of headroom over a floor area of at least 70 square feet, measuring at least 7 feet in each direction. At one family's, the Lyons' house, this meant that only a portion of the attic was usable, though some of the low-clearance area was tapped for storage.

Floor support

Attic floors generally need to be reinforced with additional joists and a subfloor. The Lyons used a web of 16-inch-deep engineered trusses to accommodate wiring, plumbing, and ductwork, then topped the plywood subfloor with oak or tile. (Keep in mind that deep trusses will cut into headroom.) "Houses built before 1950, and some built after, may also need foundation work," says architect Stewart Davis, especially if the project involves raising the roof, as the Lyons' did.

Ventilation and insulation

Heat and moisture rise. This often means having to add air-conditioning, ceiling or window fans, and/or windows. The Lyons installed windows at each end of the roof to promote cross-ventilation. A layer of spray foam insulation under the roof and in the walls will help cut their heating and cooling costs.

Source: This Old House


Ingrid Spencer


Ingrid Spencer shares her wealth of knowledge on tips and tricks for today's homeowner in "This Old House" magazine.

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