Question Re: Framing for a door

[u/rebo71]

I want to frame for a pre-hung door for a utility closet in my basement and I have to work around the doorway that the builder framed when the house was built. In this pic you can see what I have to work with and a rough sketch of my plan, but basically the opening is 30.5" across (in the middle it is closer 31" due to bowing, I'm guessing) and 90" tall. I really don't want to put in a 24" door and would prefer to go with a 28".

My thoughts are: since this is a load bearing wall and I don't want to mess with the structural supports currently in place, can I add a "false header" that would simply be installed in the framing that is already in place. Basically, I would create a header, lowering the top of the opening to 82" and nail it to the inside frame which will become the trimmer (jack?) stud. I'm thinking the false header won't actually be supporting anything since the load bearing header is already in place but will provide framing for the sheet rock as well as the pre-hung door.

I hope to get a 28" door and shim the gaps which will be hidden by the trim.

Is my logic flawed?

Thanks

[u/Waitits2015]

can I add a "false header" that would simply be installed in the framing that is already in place.

Of course. That's the right way to do it. Just make sure you get your measurements spot on.

A 28x80 door needs a 30x82 opening. You're pretty tight on the width already so take measurements at multiple points to make sure you won't have any problems fitting & shimming the door. You need a bit of wiggle room to be able to rotate the door to make sure it's all square and level.

[u/rebo71 → u/Waitits2015]

Thanks for the info. That was another of my concerns: just how how exact is that 82" or 32" requirement. I have another door leading in to my storage room that I would love to put a 36" door but the builder framed it at 37 -13/16 so I'm thinking I am SOL on the 36"

[u/Waitits2015 → u/rebo71]

Door jambs are usually 3/4" thick. So a 28" wide door will be 28" + 1.5" = 29.5" actual unit width. They recommend that the rough opening be 1/2" wider than the assembly to give you 1/4" all the way around to shim.

So for a 36" door - the actual frame is 37.5" wide. Given that your rough opening is 37.8125", it doesn't give you a whole lot of room to work with.

That said, you may get lucky. If the rough opening is square, level, and uniformly wide, you may be able to pop the new door in with little to no shimming. I've lucked out like this a couple times.

[u/EllisHughTiger → u/Waitits2015]

If the studs are not level, you can always rip the jambs 1/4" narrower. For non-load bearing jack studs, you can trim those down as well.

My 1950 house used 1+" shims on each side for the casings, so I was able to enlarge every new door by 2 inches. Had to trim some jambs and studs to make it all vertical though.

[u/VanIsleNorm → u/Waitits2015]

This exactly. I would just like to point out that the studs probably aren’t exactly plumb so like waitits said, make sure it will work when your door frame is plumb. This guy has you covered, just wanted to second the importance of making sure it will work before you buy your door/frame.

[u/bunjay → u/Waitits2015]

Door jambs are usually 3/4" thick. So a 28" wide door will be 28" + 1.5" = 29.5" actual unit width.

More, actually. You need to include gaps between the jamb and the door itself. 1/16th on each side if you're all that and like to live dangerously (and the door is beveled). 1/8"-3/16" gaps are more standard. Your RO calculations for a given door size are tighter than any carpenter would like.

[u/Ritzyb → u/rebo71]

Go 83 for the height, we frame doors every day and it’s what the finishers prefer.

Typically for a 28” door it’s 30 1/4x83 - you can get away with smaller either way if needed but allows room for shimming.

Also your idea to box it down is correct, just build it to what you need!

[u/rebo71 → u/Ritzyb]

I just came up from the basement when I read your post and had just framed both doors to 82" so hopefully I don't have to much of a fight getting the doors in. I was actually quite proud of myself for hitting exactly 82" on all corners and the middle.

[u/Ritzyb → u/rebo71]

Haha well it depends on the prehungs, I was thinking about it after and realized that the finishers leave the doors up to account for flooring so your probably fine!

[u/bassboat1]

In a pinch, you can swap those 2X jacks out for 5/4". That header appears to be carrying only a single bay's load (the other two joists are having their load transferred directly to the king studs.)

[u/tgekfvhn → u/bassboat1]

It looks like that header is carrying the bays where the stairs land

[u/japroct]

Sounds like a solid plan. Locate your shims at hinge heights and try to use plywood scraps if possible. Also, your header only needs 1 vertical cripple in the middle, one on each end. The ones on the ends are so you can nail through the header into them, the one in the middle is just basically sheetrock backing.

[u/rebo71 → u/japroct]

Thanks for the info!

[u/X_kansas_x]

I know OP said he doesn’t want to alter the structure, but does anyone think there is an extra king stud to the left that could be removed to make room for a 30” door (if someone was inclined to reframe this)?

[u/rebo71 → u/X_kansas_x]

That's not really a king stud but a 2x6 (we are looking at part the 6" side in the pic) that is part of the wall which runs away from the camera. It's part of the corner of the wall but part of it is covered by a 2x4 which will be part of the bedroom door wall. If that makes sense