Long Island, N.Y., building consultant Mike Slogatt often gets called in to help contractors who don’t want to touch big sliding and folding door systems—and he understands why. A recent job in the Hamptons included a 33-ft.-7-in. lift-and-slide with an $85,000 price tag before installation.
Columbia, Mo., custom builder Jake Bruton, whose crews at Aarow Building also install lots of these doors, is blunt about the stakes. “These aren’t going in homes where the clients will be understanding if the door doesn’t work properly,”” he says. “And if there is a problem, they can afford a lawyer to help you understand.”
There’s no margin for “close enough.” Every decision—from rough openings to water management—either enhances your reputation or threatens it.
Extreme Accuracy Needed
Some carpenters worry about the door itself, but what’s most critical is the rough opening. To be blunt, it needs to be perfect —more precise than most builders are used to. “The floor at the base of the opening has to be flat and level to 1/16 of an inch,” says Slogatt. It can’t pitch outward or inward, and the tiniest hump will cause problems with the door’s operation. “It won’t be able to seal.”
In a remodel, the floor will have to be sanded and/or planed flat. If shims are required, they need to be set with a laser level.
The jack studs supporting the header can’t be even slightly out of plumb or out of plane. “Cross-leg framing will be hard to seal,” says Slogatt. With new construction, the contractor can double-check for plumb and string the opening to avoid an out-of-plane opening before drywall gets hung, but that’s seldom possible on a remodel. If the door is installed with the jambs on either end plumb and in the same plane (and it absolutely has to be installed that way), then the bottom one jamb won’t line up perfectly with the drywall, which will complicate the trim. Tapered shims will be needed behind the jamb to resolve the issue.
Headers are a huge deal. “A 16- or 20- ft long header is going to deflect over time,” says Slogatt, “but it can’t [deflect] more than 1/8 in. max.” He points out that the door frame’s head jamb will also be 16 or 20 ft. long, and that to keep it from sagging it needs to be screwed up into the header. A sagging header will push the jamb down, causing the door to bind.
Big doors are seldom installed in gable end walls. But if the job calls for that, and if the room has a cathedral ceiling, wind loads become an issue. “The wall could wiggle and cause problems for the door,” says Mike Whalen, lead carpenter and project manager at DBS Remodel in Poughkeepsie, N.Y. In addition, if it’s a framed roof (rafters rather than trusses) with a structural ridge beam, then the the post that supports the ridge will be interrupted by the opening. You will need a structural engineer to resolve these issues.
In a retrofit where there’s a floor above, beam depth can be an issue. “If it’s a 20-ft span and you need a 16- or 18-in. depth to get the required stiffness, the RO could end up too low,” says Whalen. One solution is a flitch plate beam: a steel plate sandwiched between two LVLs. However, the beam might end up thicker than the wall it’s going into. If so, Whalen leaves the outer face proud of the existing framing and uses built-up trim on the exterior to resolve the difference in wall thickness.
Of course, long headers must be engineered, but don’t blindly accept the engineer’s spec. “One of my PMs had to tell the engineer that the deflection on the beam he specced would be too much,” recalls Bruton. The engineer responded that it met standard specs, but the PM pointed out that it wasn’t a normal job. “We explained that it wasn’t a regular patio door; it was a lift-and-slide with tight tolerances.” The contractor needs to confirm that the beam will be stiff enough.
Keeping Water Out
Metal flashing pans are a must, and the pros we spoke with prefer, whenever possible, to set the pan and the door track into a recess at the base of the opening. That way, water seeping through the threshold won’t threaten the interior but will drain outside.
This also pleases the homeowners: They like it when the interior floor, the door threshold, and the exterior deck are flush.
Flashing details are less critical for doors under a roof, so Bruton always advises them. “Big openings deserve big overhangs,” he says. When we spoke with him, he was in the midst of a job with 19-, 17-, 16-, and 11-ft. lift-and-slides, and was able to convince the homeowners to put all but one under a roof. He also steps up water management details—for instance, adding liquid sealant to the leading edge of the flashing tape.
Unprotected doors in extreme environments warrant another level of waterproofing. Jerry Caton has installed big doors in luxury beachfront homes on Martha’s Vineyard, Mass., for 25 years. “Our most recent job included two 36-ft. sliders,” he says. The homes he works on are designed to capture ocean views. “If the view is to the northeast, that’s where the glass goes.” Most homes have a sleek modern design with nothing to protect the door.
The challenge is that Nor’easters hammer the New England coast on a regular basis. Think horizontal rain driven by wind gusts in excess of 60 mph. “I have nightmares about water,” he says.
An expensive but effective flashing detail helps him sleep better. “We cut a 2-mm-wide groove into the top edge of the jamb, and leave the frame an inch proud of the framing. We tuck copper flashing into that groove, and fill the gap behind it with non-expanding foam,” says Caton. He has never had a leak. “It’s foolproof.”
What’s not foolproof is homeowners. One family didn’t lower the operable panels in their big lift-and-slide into the locked position, which allowed wind-blown rain to get under them. Caton now tells everyone to look at the top of the door. “I tell them that if the gap above the operable panels lines up with that over the fixed panels, they have been lowered.” That advice has been very effective.
Tools and Time
Given the high stakes with these doors, instructions must be followed to the tee. “Manufacturers are specific about how they want these installed,” says Slogatt. “Don’t take shortcuts and don’t leave any parts out.” Doing so risks being blamed if there’s a warranty callback.
He also notes that fasteners and hardware aren’t interchangeable between doors, and that contractors who assume they are will end up in trouble. “If you put the wrong bolt into wrong hole, it will snap,” says Slogatt.
One contractor on a home with multiple big doors opened the boxes to get sill pan dimensions, then threw the fasteners and hardware in a pile. They called Slogatt when they couldn’t figure out what part went where. “I had to spread everything out on a table and sort through them.”
Finally, it’s important to have the right tools. If you need a #2 Phillips driver, you want to know it’s in the toolbox.
Slogatt recommends having an extensive set of drill bits for pilot holes, not just the common ones, a drill index to ensure you drill the exact size hole for each fastener, and some screw wax. “If you snap a stainless-steel screw, getting it out will be nearly impossible.”
The bottom line is that a big door installation is a precision job with no room for error. When the tolerances are this tight and price tags this high, builders who slow down, plan ahead, and follow the details are the ones who sleep at night.