Doors that slide away into walls is an old design that still makes sense. A pair of 3- or 4-foot-wide doors can turn two rooms into one or vice versa, and free up floor and wall space where standard doors would swing. But you rarely see pocket doors in new homes because they're not hung on the structure like hinged doors; they're built into it. That's more complicated, labor intensive and expensive.
Suppliers offer prefab units with a hollow center for the door that's covered by framing. You or your contractor install these pockets next to the opening instead of standard 2-by-4 studs and then add drywall. But most pockets are rickety. I've tried several, and even using many of the longest possible fasteners, if you push on the drywall over the door cavity it bows. That's because the 3 1/2 inches of support in each full stud has been reduced to a 3/4-inch strip on each side. Leave a 2-inch space for the door in the middle and that's what's left. It's not much.
A few extras can add strength to underframed pocket areas. One is to apply the covering wallboard with glue and screws for extra stiffness. Another is to trade up from standard 1/2-inch to beefier 5/8-inch drywall. The most helpful is to frame the wall and buy a pre-framed kit for 2-by-6 instead of 2-by-4 construction. There is still the hollow 2-inch core, but 1 3/4-inch instead of 3/4-inch framing on each side.
Another option is to custom-frame the pocket on-site. It could be done with 2-by-4s on each side of the pocket. But that's two 3 1/2-inch studs plus a 2-inch hollow, plus drywall —10 inches wide overall. Or control the width using 2-by-4s or 2-by-6s but turned sideways. That gives away some lateral strength, but the wall width overall shrinks to 6 inches.
Vertical loads get more complicated — in partition walls that divide floor space, and more so in bearing walls that carry structural loads for a second story, the roof or both. At any opening where studs are removed you need a header, constructed with two 2-by-6s on edge. The header carries the load that used to be carried by studs that were removed.
In an existing house this becomes a complex structural project — and typically requires a building permit. Pocket doors that are 4 feet wide would require a header that spans the opening of 8 feet, plus another 4 feet on each side where the doors tuck away. It's 16 feet long, heavy, unwieldy and often constructed of two 2-by-10s or more depending on the load above. And in remods you can't pull 16 feet of studs out of a bearing wall without installing temporary support walls as the work gets under way.
Both prefab pocket kits and custom framing on-site are challenging for most DIYers. The sliding track must be straight and level, and on double doors meet exactly in the middle. That means the header must be dead on as well — and strong enough to carry the extra weight of doors and hardware. Hollow-core doors are no problem. But a pair of standard-size solid-core doors can weigh more than 200 pounds.
Another tricky part? Any face hardware like a handle or pull has to be recessed (mortised into the door) or it will catch at the jamb. Nothing can protrude into the cavity, not even the tip of a drywall screw, or the door will stick on its way into the wall. Overall, it's exacting construction.
Single pockets are easier projects. They make sense wherever space is limited and a standard door swing would be in the way. Trying to find space for a powder room tucked under the stairs? With a pocket door you don't have to allow for the door swing between a toilet on one side and a sink on the other.
They also solve problems in accessible designs by eliminating the process of opening a swinging door from a wheelchair and maneuvering around the swing to close it on the other side.