Wednesday, December 28, 2005

Replacing the Patio Door

The Patio Door is a sliding door from the Living Room out to the Back Porch. It seemed to be a fairly standard unit when it was installed by the Builder (1986). When the house was broken into (1992), they pried the door open. The lock was a simple cast-iron piece that just broke. It only cost a couple of bucks to repair the lock.

So when the door started to not slide easily, I figured it was time to upgrade to a much nicer door. From the advertising I see, Andersen and Pella would be the main choices. Home Depot carries Andersen, and those doors looked very nice. Pella had an office on Burnet, and they also had very nice doors. We went with Pella. They could do the whole job -- removing the old door and installing the new one. We got a triple-pane glass, wood door, with Argon-Filled Low-E glass, Satin nickel hardware and duets between the glass. $3620.29. The contract was signed 11 July 2005; it was installed on 23 August.

This Pella door was so well built that it introduced a problem. When we let the dog out in the back yard,
we couldn't hear it bark at the door to be let back in! To fix this, we got a baby monitor and put it outside the door. When the dog barked, the baby monitor would pick it up and transmit it to the inside of the house.

But, incredibly, despite all the thought and work that went into the door, I found the locking mechanism so badly designed that it made the door unusable. In our home environment, it is a disaster waiting to happen. The basic design of the lock is flawed. All doors have 2 basic independent attributes: they are either (a) open or (b) closed, and they are either (1) locked or (2) unlocked. In the following picture, the door is unlocked.



The Pella door's design introduces a new state: (*) primed to lock, but not locked. The locking mechanism moves the door from the (2) unlocked state to the (*) primed to lock state. The next following change from (a) open to (b) closed will also cause the door to move from (*) primed to lock to (1) locked. This violates many obvious design criteria which are necessary for any well-designed general door:

(A) There is no visual cue or clue as to what state the door is in. If the door is closed, and the locking mechanism is down, the door may be in either the (1) locked or (*) primed to be locked state. So you cannot tell whether the door in the following picture is or is not locked -- it may be locked, or it may be only primed.



(B) A (b) closed door cannot be put into a (1) locked state. The locking mechanism must put into the (*) primed state and then it must be (a) opened and then (b) closed to lock it.

(C) The exterior key cannot put the door into a locked state, unlike probably any other lock in general use.

This design means two undesirable common situations will frequently occur:

1. A person will approach the closed door, and put the locking mechanism down and then leave, thinking the door is locked. In fact, it is not locked, but only (*) primed. This creates a security risk -- the house is unlocked although it looks locked.

2. A person will open the door. Since a locked door will not open, they will then go thru the door, closing it behind them. But since the door may be in the (*) primed state, closing the door will then lock the door, locking them out. This happened to us twice in the first week.

As I said, this is a disaster waiting to happen. This is a door is unlike doors that most people will have encountered. Children, guests, visitors. It is unreasonable to expect these people to be taught how to use the door before they use it, nor is it reasonable to expect that they will remember the peculiarities of this design.
Unlocked doors that look locked (and should be), doors that lock behind you, and doors that are not locked when you want them to be, and then lock when you don't want them to and not well designed.

This locking design is apparently used on all the high end sliding doors -- the Architect Series and the Designer Series -- from Pella, and it was beyond their ability to replace it with just a simple lock.

So we had Pella come back and take the door out.

We replaced it with an Andersen door. Basically the same, but only double paned glass (not triple paned) and so without the built-in duet blinds. $1597.68 on 19 November 2005. It was installed on 28 December 2005. $400.

Astoundingly, even the Andersen door did not have a simple lock. The Andersen door has a hook type latch and if the door was closed, there was insufficient clearance for it to swing and latch. So to lock a closed door, you had to first open the door a bit and then latch it closed. But the Andersen people were just bad builders, not bad designers, so taking a file to the latch, I was able to file it down so that it cleared. Now we can lock a closed door without having to open it. I really do not understand how these two major door manufacturers can be so clueless in what is an acceptable sliding door.

But finally, we have a nice sliding door. I put two coats of polyurethane on the wood trim.