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  Exterior Bifold Doors (For DOGS!)  

It's funny how you get used to friends being the same age—as you get older, they get older. Nothing seems to change. But a few years ago, when she turned 10, my best friend started getting older than me. At first I didn't notice any difference at all. She ran as fast as ever—even though she's never been able to catch even one squirrel in the back yard. Then last year, when she turned 61, her hips started acting up. Now that she's in her mid-sixties, she can't make it through the back door with banging a leg on the bottom lock rail.

I knew I had to do something to help her out, before she ended up in a wheel chair, so I started looking at those new bifold doors, in extra large. I wanted to intall it low, so she wouldn't bang a leg or have to stoop down to get in or out. Lucky me, I found one that just fit the side light flanking the French door in my office.


While Whitney watched (and checked out the new door), I fastened a mahogany step to the old sill, so the lock on the new door would have enough clearance to rotate.



The new door ( 17 3/4 in. wide) fit perfectly into my sidelight jamb (18 in. wide). I fastened the frame right to the casing and the mull.


I cut a piece of 1/4-in. mdf exactly the width and length of the new sill, then tipped the template into the sidelight opening and scribed both ends to fit around the jambs, making a few corrections and notes once I had the template in place.


Cutting a radius on each corner of the template prevents the new sill from being a pain in the thigh.



Without some 6/4 mahogany stock on hand, I laminated two pieces of 3/4-in. material, used the template to mark the cut lines, made the cut outs with a jigsaw, then fastened a piece of 3/4 x 3/4 in. scrap material to the bottom of the new sill, right at the front. Running the sill through my surface planer cut a perfect angle for drainage, leaving a 1 3/4-in. flat at the rear edge, for the sidelight to swing over.


After sanding, I finished the sill with Cabot's Clear Seal.



Modifying the door took the most time, but even that was mostly a matter of patience. To remove window stop and glass, I use a pair of 5-in-1 painter's tools, a small molding pry bar, a utility knife, and some shims.



Start by cutting the stop loose with the knife. Don't push hard on the knife. Make repeated cuts, first at the top of the stop, then along the glass at the bottom of the stop. Work the knife in slowly.



Next, tap one of the scrapers slowly between the stop and the sash, wiggling the scraper and slowly prying the stop loose.


Wiggle the second scraper in alongside the first, then pry one back against the sash while prying the other back against the stop. Use the pry bar to help lift the molding out from the miters.


Removing the glass requires nothing but shims and patience. Flip the sash over to the sticking side, then drive a shim into each corner.


Drive shims into the center of each sticking span, too, then slip the two scrapers between the glass and the stop, and pry gently in both directions.


The corners are especially delicate. Slide a scraper into each side of a corner so that the glass and the sticking are well supported, then lift the scraper handle up and gently force the glass down. Work each corner slowly--break the bond between the adhesive and the glass, moving from corner to corner until the glass drops free.

If the bond between the glass and the sticking is persistent, drive additional shims along the sticking to break the bond, not the glass.


Once the glass is free, use a softwood block, cut at about a 30 degree angle, and tap the mullion away from the glass. To prevent the mullion from splintering, keep the block tight against the very end of the mull.


I used a Festool saw and guide to cut precisely along each edge of the bottom lock rail.



Remove the remnants of the dowels by drilling several holes in the dowels, each hole slightly larger then the last, then chisel off the waste and clean the coped joint carefully.


Raise the sash slightly off the workbench so the bottom rail doesn't scrape on the bench top. Clamp the sash to the bench, then slide the lock rail onto the stiles. Glue both stiles liberally.



Tight Bond III works well because it's waterproof and water clean up. Tap the lock rail slowly into position, then clean up the corners with a toothbrush and clean water.



I trimmed the bottom of the sash with a straightedge.


After clamping the stiles tightly against the lock rail, I drilled pilot holes and secured the joints with FastCap PowerHead screws. These square-drive steel screws have 9/16 flat heads, which will NOT pull through. The oversize heads also have nibs on the bottom which help counter sink the heads.



Flipping the sash over, I tapped the glass stop back into place.



Then secured it with stainless steel pins.


By the time I finished modifying the door, the sill had dried. It slipped into the jamb perfectly.



After hanging the door back on the hinges, I re-installed the door shoe.



Next I cut down the screen and secured it back into the screen rabbet in the jamb.


The hardest part remained. For about ten minutes, I stood outside and called my best friend, Whitney.


Finally I broke out the dog treats. It only took a few to coax her through the new dog door.


For exact human comparisons to dog years I relied on this calculator: http://www.onlineconversion.com/dogyears.htm

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