At my new home, I built a small guest cabin down by the river (reservations are booked years in advance, so good luck with that!). I wanted to open up the west wall of the cabin, along the river, to both the sight and the sound of the water. But I couldn’t afford a 12-ft. wide commercially manufactured sliding door unit. And besides, I wanted it to look cool. So I made the unit myself.
A Note from the Publisher:
WARNING: POTENTIAL CONFLICT OF INTEREST!
Many people have asked about my new home and shop, so we’re publishing a new series of articles. You’ll notice I’m using a lot of Katz Roadshow-sponsored materials in these articles—for example, the doors in this article are manufactured and provided by Plastpro. We choose our sponsors carefully, from among the best manufacturers in the industry, and that’s why I chose to use their products on my own home, too.
A Careful Drawing
I started with a very carefully drawn plan in SketchUp, with no idea what the rough opening would be until I finished the drawing. The only thing I knew for sure was that I had to use 2/8 doors. I could have made the opening wider by using 3/0 doors—I had the wall space, but I wanted to save wall space inside the cabin for the wood stove and some furniture.
First I drew the four 1 3/4 x 2/8 x 6/8 doors with glass panels for the interior of the wall; then I drew in four 1 3/4 x 2/8 x 6/8 doors with empty panels for screens on the exterior of the wall.
I knew I had to attach check rails—really check stiles—to the overlapping stiles so that I could properly weatherstrip the opening. I didn’t worry a lot about how much the doors overlapped, I just wanted them to seal. I added ½-in. x 1-in. strips to the back of the lead doors and also to the front of the rear doors. Before I fastened the strips, I rabbeted them so I’d be able to slip in Q-Lon weatherstripping.
With the check stiles defined, along with the spacing between the doors, I was able to draw the head jamb. I planned to kerf the tops of all the doors, on both sides, so the weatherstripping would seal the doors to the head jamb, and also provide a smooth surface for the doors to glide on.
Rather than trying to attach the parting strips with just screws, I wanted to groove the head jamb so the parting strips would be perfectly straight and all the spacing for each door would be perfect—otherwise, I knew I’d end up with one door that had too much wiggle room and another door that didn’t have enough!
Like the doors—which are fiberglass and made by Plastpro—I wanted the sill to be impervious to the sun and weather, especially near the river! So I planned to use Plastpro’s Polyfiber Jamb material and I knew I’d have to rip it and laminate the sill from several pieces.
The Polyfiber jamb stock has an oak grain, which takes stain nicely, so instead of beveling the top of the outside exterior nosing—and losing the grain texture—I decided to rotate that piece and bevel the back edge before gluing up the sill.
The overhang on that side of the cabin is 5 ft. deep—plenty of protection from rain and snow. The landing outside the pocket doors is 4 in. beneath the sill, which also provides protection from rain and snow. But I still planned to kerf the bottoms of all the doors, on both sides, to weatherstrip and seal the opening from air leaks and wind-blown weather.
The last critical detail was designing weatherstripping for the backs of the doors, which was pretty simple—I added a piece of 1x to the back of the rear doors and made it wide enough to strike the removable jambs, but not so wide that it would rub on the interior wall of the pocket. I planned to weatherstrip that stop, too.
I wasn’t the only one that worked on designing these doors. I had a lot of help from my brother Larry and from Todd Murdock, too. Larry—through his store in Southern California—helped me collect all the hardware. He suggested adding jamb blocking to the rear doors, too, so that in the winter, when the screen doors were retracted and in their pockets, and the primary doors were closed, you wouldn’t see inside the pockets.
Those jamb blocks are also handy because the lead doors can push the trailing doors back into the pockets.
Once I had the details for the check stiles, the sill, and the head jamb worked out, it was easy to determine the O.D. of the doors and the I.D. of the jamb.
Likewise, once I had the O.D. of the doors and the I.D. of the jamb, it was easy to determine the depth and the O.D. of the pockets.
I didn’t want to worry about the exact header height, so we set the rough header much higher than necessary. I also didn’t want to cut the doors down, not even a little, because I knew the pocket mortises for the wheels would cut deep into the bottom rails.
And with the rough header set high, I figured we’d start by setting the sill, then use the full-height doors, riding on the track, to determine the precise height of the head jamb. Once the doors were all on the track and engaged in the head jamb, I figured we’d set the jamb legs and adjust the I.D. of the opening so that the stops on the backs of the doors kissed the backs of the jamb legs just as the lead doors touched. I know, that’s a lot of figuring…
But I honestly think I never would have tackled this project if it weren’t for SketchUp. There were too many details that I might miss—too much to try and keep in my head. Even one mistake could prove fatal to the function of the doors. I not only used SketchUp to test and prove that the design would work, but I also used it to develop a step-by-step schedule for the installation.
I used the same wheels that are found on many custom wood sliding doors and purchased them through Functional Fenestration, a company that specializes in sliding door hardware. The tandem wheels come in three types: stainless steel, which can carry up to 500 lbs. and is a necessity for coastal homes; steel, which can carry up to 400 lbs.; and nylon, which is rated up to 250 lbs. I used the nylon wheels because fiberglass doors are light, even with glass, and the nylon wheels roll very smoothly. Once I had the wheels in my hand, I made a mockup.
I also wanted to test the space at the head jamb I planned to allow for each door, along with weatherstripping on both sides.
Building the mockups also provided the opportunity to dial in each dedicated router. The kerf-in weatherstripping for the head of the doors was smaller and required a narrower kerf than the weatherstripping at the bottom of the doors. The mockups also allowed me to test my router template and set router depth stops for the two-step mortises each wheel required. With four glass doors and four screen doors, I had to cut pocket mortises for 16 wheels. Definitely a production job.
I made a two-step template for those mortises. Router templates are so easy to make. Once you know the O.D. dimension of your template guide, just subtract the size of your cutter and you’ll know exactly how much larger to make the template for your hardware. In this case, the template guide was 1/8 in. larger than the router bit we cut with, so I added 1/4 in. to the I.D. of the template guide.
The wheels measure 6 1/4 in. long x 3/4 in. wide. So I made the I.D. of the template 6 1/2 in. long by 1 in. wide. First I ripped a 1-in. wide strip off a 16-in. 1×4. I cut that piece in half and glued it between two 8-in. pieces of 1×2, spacing those pieces 6 1/2 in. apart.
To be sure the mortises were cut right in the center of the doors, I attached 1/2-in. x 3/4-in. guide strips to the back of the template. And to position the mortises exactly the same distance from each edge of the door, I fastened a stop block between the guide strips.
The mortise for the wheels had to be cut with two steps: one shallow step for the shoulder of the hardware where the screw mounts, and a much deeper pocket for the wheels. The pocket had to measure 4 3/4 in. wide, so I pre-drilled for a pair of long steel screws, centering the screws and spacing them 5 in. apart. Using screws for two-step templates is a handy technique. I’ve used them for lock strikes that require large dust buckets, for Soss hinges, for flush bolts, etc.
Processing the doors
Once the mockups were completed, the hard work, at least the thinking part, was over. Fortunately, there were two of us doing all that thinking. Scott Wells was with me every step of the way, and there wasn’t a chance that he was going to let me do any of the actual processing. I was allowed to stand around and watch…and take pictures, and even a little video.
We started on the tops of each door and ran a slot cutter to kerf for the weatherstripping. Then we switched to the bottom of the doors where most of the work took place.
|We attached the two-step router template with a temporary screw.|
|Pre-set turret stops made it easy to adjust the router for each step.|
|We marked the template just to make it clear that the center section was cut deep. The pilot holes for the screws run through the top of the template and down into the bottom, too, so the template won’t split.|
|After we cut the pockets, we routed a kerf in the bottom of the door for weatherstripping. The two interior kerfs were machined by the manufacturer. I’m not certain why!|
|We even made a template to position the exact location of the access hole for the wheel height adjustment.|
|And drilled the pre-finished doors with a forstner bit.|
|Once all the sawdust was cleaned out of the mortises, we installed each pair of wheels.|
|Yes, the adjustment screw was centered in the hole we drilled!|
|Finally, we installed the weatherstripping in the bottom of each door, and then we carried the doors down to the cabin.|
The Sill and Head Jamb
Unfortunately, Plastpro doesn’t sell 5/4 flat stock, so for the sill and the head jamb we ripped down the widest rabbeted polyfiber jamb stock we could get, and discarded the 3/4 x 1 7/8 rabbet—we wanted only the 1-in. un-rabbeted section of each piece. Then we joined all those rips to make the sill and head jamb, reinforcing the laminations with PL Premium and Dominos.
|Then we joined all those rips to make the sill and head jamb, reinforcing the laminations with PL Premium and Dominos.|
|For the beveled section of the sill, on the exterior of the cabin, I attached a piece of 3/4 x 3/4-in. scrap to the face of the laminated sill using a few small spots of 2P10 glue, which is easy to split off later.|
Before pre-finishing the main sill, we plowed grooves for the track using a router and guide fence. The tracks for the lead doors—both screen doors and glass doors—were continuous, but the track for the trailing door stopped midway across the opening.
We ground the ends of those tracks round to fit tight in the radius left by the router bit, and we also ground the top of the track at a soft angle, so stepping on the track wouldn’t be a problem.
To cut the continuous grooves in the head jamb, we ran the glue-up through a dado blade.
Poly fiber is very flexible. Even though the head was 1 1/4 in. thick, it still sagged and needed good support going into and through the saw—two sets of hands and continuous out feed.
We started by weatherproofing the rough opening.
|Since the landing was four inches below the sill, we had to install the small ledger and Everflashing first, then work our way up and across the sill.|
|We used a peel-and-stick membrane to seal the entire rough opening, including the full depth of the pockets.|
|Next we set the sill sections in place, reinforcing the splices with dominos and polyurethane adhesive.|
|We pressure fit the splices with blocks and shims at the back of each pocket.|
Most sliding doors don’t have to have perfectly straight or perfectly level sills—getting them pretty close is usually good enough, and adjusting the wheels is always an option. But for pocket sliders with multiple doors, adjusting the height of the wheels to accommodate a sill that isn’t straight is not an option—an adjustment with the doors in an extended and closed position could easily cause one door to be proud of the other when the doors are retracted and nested in the pockets.
|We used an 8-ft. level and a laser to check that the sill was perfectly level, all the way back into the pockets. And we checked the sill with a fishing line to be sure it was absolutely straight.|
|Instead of long tapered shims, we used flat strips of PVC to shim the sill and provide backing for the fasteners.|
|We fastened the sill down with washer-head corrosion-resistant screws, all countersunk beneath the tracks.|
|The head was built in the same manner, with splices along its length.|
|To be sure the surfaces would mate perfectly flush, every splice was reinforced with dominos. Fasteners were hidden into the parting strip grooves.|
The pre-finished parting strips were tapped into the grooves, and then secured with trimhead screws.
The doors were lifted up into the head jamb, and then the wheels set down on to the track.
|With all the doors in place, it was easy to slide them back and forth to attach the check stiles and weatherstripping.|
|Once we were confident that the doors operated smoothly, we attached the interior and exterior sill extensions using the same techniques: dominoes and PL Premium.|
After the sills were complete, and the stops and jamb blocks installed on the rear doors, we shimmed the trimmers so that the finished jambs could be installed—positioned to stop the doors the moment they touched at the center of the opening.