In ,
Don Y typed:
On 2/29/2016 8:10 AM, TimR wrote:
Take your tape to Home Depot or Lowes. What size are those doors? (the
ones for sale, not the ones you walk through at the front of
the store)

That will tell me what they *sell* but won't explain why the two
doors I observed (different homes, different widths, different
construction techniques) are "off". I would find it hard to
swallow that an architect drafting (at least) two different plans
had to resort to trimming 1/2 inch off of doors in each case.

Did *he* not know what standard door sizes were?

If I can't buy a 35.5" door, then I'll have to alter the frame
to accommodate the slightly wider door (a fair bit of work).

You seem to be giving information out about what you want to know, and why,
in increments.

Your original post was,

"Exterior door measures 35.5" wide. I assume this is a nominal 36"
door? Or, a ******* size acquired by developer when the home
was built?"

But later posts seem to indicate that you want to replace your existing
door. And, I think you may have also mentioned that you want a metal door
for the replacement.

I mention this because if there is something specific that you want to do,
it may help to state that. But, if your question is just the curiosity
question that you originally posted (and you are not asking because you want
to replace your existing door), then the responses and answers would be
different.

When I have investigated the possibility of replacing an exterior door in
two different older homes, I encountered some of the same issues that you
are encountering. In both of my situations, I thought the doors were
36-inch doors. Basically, when I measured the opening for each door, I came
up with a 36-inch opening. But, when I measured the actual width of the
existing doors, they came up as less than 36 inches wide -- around 35 1/2 or
35 3/4 wide.

Then, when I went to look at doors for sale (just the door slabs
themselves -- not prehung doors with the frame included), I kept coming up
with doors that were 36 inches wide. That meant that if I bought a new
wooden door, it would be 36 inches wide and I probably would have to trim it
slightly to make it fit in the existing door frame opening. If I bought a
metal door, it would be a problem because trimming 1/4 inch off of the width
of a metal door would not be a viable option (I don't even know if it is
doable at all).

So, that means that my two options are to:

1) buy a 36 inch wooden door and trim it slightly to fit the existing
opening; or,

2) buy a prehung metal door and replace the existing door and frame entirely
(which meant more work, dealing with the having to remove the existing trim
and frame around the original door etc).

I think that means that the answer to your original question is that, yes,
nominal 36 inch exterior doors on older homes were often only nominally 36
inches and were in reality about 35 1/2 or 35 3/4 inches wide to fit into a
36 inch wide opening.

Meanwhile, one of my possible exterior door replacements would have involved
a door that is 84 inches high -- not the typical 80 inch high doors that
they make now. That would have meant ordering a custom size door. And,
since I would be ordering a custom size metal door anyway, I thought that
may mean that I could order a custom metal door that was 35 3/4 inches wide
and 79 3/4 inches high to fit the existing opening. I never did check to
see if I could order a special size metal door with those exact
dimensions -- partly because I didn't have the heart to buy a metal door
that I only hoped would fit the existing opening correctly.

In the end, I wound up not replacing either door -- at least not yet. I
repaired one existing door and I just left the other one (the 84 inch high
door) as is and didn't replace it.

Those were my experiencing with this issue in case it helps.