Silly Door Framing Question

[SeattleCraftsman]

So I have finally gotten around to framing my door openings and I have mixed information. I'm intending to install 28" wide, 7'0" (84") tall prehung doors. I get that the rough opening should be 2" larger than the size of the door, so in this case 30" x 86". What I am confused about is whether the rough height is measured from the subfloor or the finished floor. Can anyone clarify this for me?

Thanks!

 

[nealtw]

The rough framing of the house is done on the subfloor. Although now with hard we are often asked to frame it a bit higher. Keep in mind you don't nail the door frame at the top and with the size of door molding today, a little to high is a safe bet..

BTW , bi-fold and outswing doors, are framed different.

 

[Snoonyb]

So I have finally gotten around to framing my door openings and I have mixed information. I'm intending to install 28" wide, 7'0" (84") tall prehung doors. I get that the rough opening should be 2" larger than the size of the door, so in this case 30" x 86". What I am confused about is whether the rough height is measured from the subfloor or the finished floor. Can anyone clarify this for me?

Thanks!

So, this is a remodel, and you should have some Idea what the finish floor material will be.

In rough construction the door jambs are measured from the subfloor and the doors are cut for the sweep, UNLESS, the finish floor product/s are known, then adjustments can be made.

 

[CallMeVilla]

Just finished another door install yesterday. Frankly, I find the 2" extra width on the RO to be irritating because it necessitates larger shims to center and plumb the door. Maybe its just me but I think a 1" extra RO would be enough if the framing is plumb and square as it should be if you are building it carefully on your own.

Also, if you are going to carpet the floor, shim the door jambs off the floor about 3/8". This allows the carpet to be tucked under the jambs without having to saw them off. It leaves enough clearance so the door doesn't rub on the carpet. Also, if your floor isn't level you can shim the hinge side then adjust your latch side up or down independently of the hinge side.

Door casing kits are now available which are pre-mitered. Really speeds the finish carpentry. If you are using a prehung door, make sure the final gap between the door and the jamb allows no less than 1/8" gap for finish paint. If your gap is too tight, the final door will rub on the paint ... a bummer after all that hanging and casing.

 

[nealtw]

Just finished another door install yesterday. Frankly, I find the 2" extra width on the RO to be irritating because it necessitates larger shims to center and plumb the door. Maybe its just me but I think a 1" extra RO would be enough if the framing is plumb and square as it should be if you are building it carefully on your own.

Also, if you are going to carpet the floor, shim the door jambs off the floor about 3/8". This allows the carpet to be tucked under the jambs without having to saw them off. It leaves enough clearance so the door doesn't rub on the carpet. Also, if your floor isn't level you can shim the hinge side then adjust your latch side up or down independently of the hinge side.

Door casing kits are now available which are pre-mitered. Really speeds the finish carpentry. If you are using a prehung door, make sure the final gap between the door and the jamb allows no less than 1/8" gap for finish paint. If your gap is too tight, the final door will rub on the paint ... a bummer after all that hanging and casing.

Wait a minute, what are you talking about, 28 " door with 3/4" jam on each side with a 1/8 gap on each side, you would frame it 29", A pre-hung door is 29 5/8 " wide. plus or minus

 

[SeattleCraftsman]

So, this is a remodel, and you should have some Idea what the finish floor material will be.

In rough construction the door jambs are measured from the subfloor and the doors are cut for the sweep, UNLESS, the finish floor product/s are known, then adjustments can be made.

Sure, adjustments can be made, but I have to know what the "standard" is to know which way I should adjust. Does measuring from the subfloor give me a 3/4" door gap over 3/4" hardwood, or (more unlikely) a 1/4" gap over 3/8" hardwood?

I don't have the prehung doors on hand, so I'm missing the measurement from the bottom of the jamb to the bottom of the door.

 

[bud16415]

Wait a minute, what are you talking about, 28 " door with 3/4" jam on each side with a 1/8 gap on each side, you would frame it 29", A pre-hung door is 29 5/8 " wide. plus or minus

So what you are saying is a 28” door with jamb measures 29.75” (.75 jam x 2 and .125 gap x 2) and you frame it to 30” that leaved .125” per side rough framing can be off some amount say +- 1/16” That would leave you in the worst case only 1/16 per side to shim.

That’s not enough is it?

 

[SeattleCraftsman]

The rough framing of the house is done on the subfloor. Although now with hard we are often asked to frame it a bit higher. Keep in mind you don't nail the door frame at the top and with the size of door molding today, a little to high is a safe bet..

BTW , bi-fold and outswing doors, are framed different.

Thanks for clarifying. I have to raise my subfloor with 3/4" plywood sleepers to accommodate radiant tubing and level the floor, so I'll measure my rough openings from the top of that.

I'm using 3/8" engineered hardwood, so I don't want to install the door frame too high, but I can leave plenty of space at the top to move the frame up for hardwood later if needed.

 

[bud16415]

One says 2” one says 2.5”

http://www.homedepot.com/catalog/pdfImages/80/80ffca51-50ab-495d-90ff-f73bf4d7ab07.pdf

http://thequickdoorhanger.com/prehung-door-rough-opening/

 

[nealtw]

So what you are saying is a 28” door with jamb measures 29.75” (.75 jam x 2 and .125 gap x 2) and you frame it to 30” that leaved .125” per side rough framing can be off some amount say +- 1/16” That would leave you in the worst case only 1/16 per side to shim.

That’s not enough is it?

That is the standard and actual door jams change from door to door and the installers never complain

 

[nealtw]

Thanks for clarifying. I have to raise my subfloor with 3/4" plywood sleepers to accommodate radiant tubing and level the floor, so I'll measure my rough openings from the top of that.

I'm using 3/8" engineered hardwood, so I don't want to install the door frame too high, but I can leave plenty of space at the top to move the frame up for hardwood later if needed.

Consider everything under the finnished floor to be sub, then you will be safe, worse case is trimming the bottom of the door, happens all the time in renos.

 

[Snoonyb]

Sure, adjustments can be made, but I have to know what the "standard" is to know which way I should adjust.

There are no standards, in craftsmanship and what you are getting is, standard practices, employed by a variety of tradesmen, of which carpentry is not the only trade they are familiar with.

There are certain assumption which have been made, based upon the OP and I have some questions; Are the walls bare studs or are you installing these jambs into existing openings with fixed header heights?

Does measuring from the subfloor give me a 3/4" door gap over 3/4" hardwood, or (more unlikely) a 1/4" gap over 3/8" hardwood?

There are other things to consider, such as, is the wall that this jamb is to be installed in, plumb?

While "automatic" door swing can be compensated by hinge adjustments, you don't want to leave a bottom gap the causes to door to stop in mid swing because it intersects with the floor.

I don't have the prehung doors on hand, so I'm missing the measurement from the bottom of the jamb to the bottom of the door.

There may be some presumed standard followed by pre-hung door vendors. but I wouldn't know that, because to me, using that product is an abdication of my responsibility to the trade I'm practicing.

 

[nealtw]

http://www.ezhangdoor.com/door-rough-opening-sizes-and-charts

 

[CallMeVilla]

Wait a minute, what are you talking about, 28 " door with 3/4" jam on each side with a 1/8 gap on each side, you would frame it 29", A pre-hung door is 29 5/8 " wide. plus or minus

I think I mis-spoke. A 32″ wide rough door opening is the recommendation is for a 30″ prehung door. That does leave 1/2" in each side for the shimming.

The gap between the actual door and the jamb must allow for paint. Some folks pack their shims between the frame and the door jamb, pushing it out of plumb. This closes the gap and can create trouble when you have the door painted.

 

[nealtw]

I think I mis-spoke. A 32″ wide rough door opening is the recommendation is for a 30″ prehung door. That does leave 1/2" in each side for the shimming.

The gap between the actual door and the jamb must allow for paint. Some folks pack their shims between the frame and the door jamb, pushing it out of plumb. This closes the gap and can create trouble when you have the door painted.

That might be true if you go down to HD and buy one one of frames that you assemble on site but if you buy jam stock or get true pre hung you get much closer to 2". maybe you have 1/4" for shims but I would never tell anyone to cheat that down because the next question will be what do I do with this door that won't fit in the hole.
Besides the question was about height.:trophy:

 

[nealtw]

I think I mis-spoke. A 32″ wide rough door opening is the recommendation is for a 30″ prehung door. That does leave 1/2" in each side for the shimming.

The gap between the actual door and the jamb must allow for paint. Some folks pack their shims between the frame and the door jamb, pushing it out of plumb. This closes the gap and can create trouble when you have the door painted.

Check you measurements again, how thick is your jam, 3/8"

 

[Snoonyb]

Check you measurements again, how thick is your jam, 3/8"

I thought the discussion was about height.

 

[nealtw]

I thought the discussion was about height.

It is, but for thousands of people that never sign up here but read these posts for quick info. I would hate to think some would read Villa's post about 1" and frame a wall and expect to put a door in the hole.:rofl:

 

[Snoonyb]

It is, but for thousands of people that never sign up here but read these posts for quick info. I would hate to think some would read Villa's post about 1" and frame a wall and expect to put a door in the hole.:rofl:

Interesting, that the presumption is, that a casual observer would arbitrarily select that single post to use as a knowledge base, rather than the total discussion, which in and of itself, would broaden ones perspective.

Besides which, it was an obvious rethinking of a previous post, based upon his experience.

 

[nealtw]

Interesting, that the presumption is, that a casual observer would arbitrarily select that single post to use as a knowledge base, rather than the total discussion, which in and of itself, would broaden ones perspective.

Besides which, it was an obvious rethinking of a previous post, based upon his experience.

That is why we discuss it.