I have an exterior door where the door slab itself is 39-7/8" in width.

Is this basically a "nominally" 42 inch door?

The door is an old wood door with some rot at the bottom so I am looking for a replacement. Right now it is an outswing door. I am debating if I should change it to an inswing door because when I had hurricane shutters installed, they were not able to install shutters for my front door because it is an outswing.

 

No, it's a 40" door......

 

Before switching it to an inswing make sure you'll have all the necessary clearances. Is the bottom of the opening as high or higher than the floor? will the open door be in the way of a light switch?

 

I went to the home improvement store to see how the doors are sized and am surprised that this seem to be manufacturer specific.

One vendor had 28", 30", 32", 36" sizes and the measurements showed these sizes are matching closely the corresponding door slab widths.

Another vendor listed same sizes but the sizes are "for door rough openings of..." these sizes.

So basically to special order an odd size one I need to know what the manufacturer goes by.

 

Marksr yes the finished floor elevation and door light switch would work. The old, never used and abandoned door bell would be on the wrong side but that has never been hooked up and I can install a wireless one easily.

This odd size door is not stocked and has to be special ordered at double the price of a 36" standard plus shipping. Hmmm...

 

A 40" door fits a 42" to 42 1/2" rough opening.

 

I'd also check prices at a store that's main business is selling doors and millwork. While they might be higher on the standard stuff it would be nice to see how their prices compare on special order.

 

That is not necessarily true. Like I said I found out it depends on the manufacturer.

I just saw this morning an exterior door with a big label of "36 in" and it is a door for a rough opening of 36" and the actual door slab measures +/- 32". Across the same aisle a different manufacturer's "36 in" is the approximate width of the door slab itself.

For some manufacturers they label a door by the rough opening size it's intended for, and for others it is the actual door slab width and you add 2" for the rough opening. I don't remember it being so inconsistent before.

 

Florida must be on a different planet than I'm on.