If I want to accomodate a standard 30" x 80" door prehung, what kind of
rough framing do I need to do to accomodate it?
I would assume the door is 30", the door jamb will add 3/8" on each side to
make it 30-3/4" assuming a 1/2" of play to level and shim the door, I should
frame it with a rough opening width of 31-1/4". Height wise, the door is
80", assume again a 3/4" jamb depth, plus another 1/2" for play, also assume
a tiled flooring with thinset and tile to be 1/2", we have a total height of
81-3/4". So the rough opening should be 31-1/4" x 81-3/4". Am I correct?
Thanks in advance,
Frame interior doors named size plus 2" (a rough opening for a 2-6
door is 2-8). Standard header height is 82 1/2" although some
carpenters frame them at 82. 82 1/2 will allow plenty of room for
A quick Google search would seem to indicate that will be a little on the
small side- this site recommends 32x82 3/4. (
http://ezinearticles.com/?Rough-Openings-For-Doors&id &7777 )
Most jambs are thicker than 3/8, so that explains the difference.
I don't remember what the 'standard' sizes are off the top of my head, but
the best way to be SURE is call or visit your supplier, and look in the
catalog or at the tag on the door, and maybe pull the tape off your belt and
double check. The catalog or tag on the casing will give the RO
requirements. Some prehungs require a higher opening to accommodate the the
'ears' at the top of the side jambs, since the top jamb fits into a rabbit
on the sides. (This is mainly on exterior doors.)
If in doubt (like if the doors are special order), make the RO a little
oversize. It is a lot easier to add shim stock, than to enlarge an opening.
I was presuming the doors would show up before you rocked the walls, of
course. I have seen situations where the client decided on tile floors
later, and header had to be reworked- it wasn't pretty. I have also seen
custom high-end doors come in with 1" or 5/4 jambs, versus the normal 3/4".
They had to replace the cripples with 1x to make them work.
Even if the rock was already done, reworking the area around the door isn't
that big a deal.
But having said all that, yes, 2" is normal, and seldom a problem if you do
your homework. A vendor won't get much repeat business if they supply doors
bigger than spec.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.