Stairs That Disappear

Most common
Wood Folding Stair
Two hinged ladder sections unfold when the stair is opened, allowing it to reach the floor. When closed, all the sections tuck up neatly inside the rough opening. Treads range from 3/4 to 1 1/2 inches thick; thinner ones typically have steel support rods underneath.
Shown: A pine stair from Sweden has 1 1/4-inch-thick treads, rated for 330 pounds. The door is weatherstripped and insulated with R-10 foam. $315, Resource Conservation Technology; 410-366-1146.

Lowest maintenance
Metal Folding Stair
Aluminum or steel folding stairs cost more than wood, but you get long-lived, riveted construction and, in the case of aluminum, significantly lighter weight. Only consider models with slip-resistant treads.
Shown: The all-steel Werner S2200 fits a 2 1/2-inch rough opening but provides a wider stair width than that of a wooden model for a 25-inch opening. Gas pistons provide a quiet assist when closing the cover door. $225, Werner Ladder

Strongest
Sliding Stair
The oldest type of attic stair is a counterbalanced, one-piece wood ladder that gently glides to the floor when you pull down the cover door. Generally more expensive than folding versions, sliding stairs are sturdy, rigid, and can hold up to 800 pounds — more than any other type. No other pull-down stair can reach as high, either; some models fit ceilings over 12 feet. Keep in mind: There has to be sufficient clearance under the roof for the ladder to slide up, and the attic floor must be free of clutter along its path.
Shown: The Bessler Stairway Co. Model 26 can handle 600-pound loads. Its weight is counterbalanced by four spring-loaded drums, which allow you to control the ladder's slide with one hand. $830, Bessler

Most Compact
Telescoping Stair
The big advantage of an accordion-style stair is how easily it fits into tight spaces, even a closet. Where a folding stair needs several feet beyond the ceiling opening to unfold, telescoping stairs extend out in a straight line. They also adjust automatically to ceiling heights; there's no trimming needed at installation.
Shown: This Czech-made, all-aluminum model weighs 120 pounds and has a load capacity of 300 pounds. The cover door is weatherstripped and insulated to R-6. $423, Calvert USA

Gaps at hinges
A sure sign that something is sagging, putting excessive strain on the hinges. Check and tighten all bolts on the stringers, and make sure the jamb is stoutly anchored, as described below. A gap like this could also result from a bottom section that has not been properly trimmed to fit.

Bent pivot arm
An arm that's out of alignment makes it difficult to open and close the stair and doesn't provide necessary support when the stair is down. In this case, the bent arm means the spring can't function as a counterbalance, increasing the strain on the pivot points and the chance of something breaking. Buy a replacement arm, available from most attic stair manufacturers, and bolt it onto the jamb.