DIY Home Improvement Forum banner

Rough Opening issues for interior Pre-hung door

6714 Views 3 Replies 4 Participants Last post by  II Weeks
My first question is when framing a rough opening 82 1/4" height for a pre-hung door do I need to take into account the type of flooring that will be installed later? On one of my doors there will be std hardwood flooring installed in that area. Is it still OK to rough out the 82 1/4 off of the bare concrete floor prior to the install of the hardwood?

2nd question: On another door I have to frame under a support beam and will not have the 82 1/4. At best I will have 80 1/4. I assume this is no big deal, just trim off 2" from the bottom of the pre-hung jam and door?

Thanks folks you have already been a great help!!!
1 - 4 of 4 Posts
Do you know the additional height of your finished floor? If so add that to the 82¼". Most prehung doors have a large gap from the bottom of the door to the frame. This looks terrible when over a hardwood or tile floor. I usually cut the side jambs to close this gap and add 1/4" from this length for my RO.

Yes for 2", I'd cut the bottom of the door. If you have a hollow core door you may cut off the bottom spacer and have to glue it back in. Because you cut the bottom, you lowered your door and this door knob will be lower than the rest.

Added: I just reread your post and you are putting this over concrete. Hold your jambs off of the concrete by 1/2".
Don't forget the sub-floor or cleat thickness. Pre-hung doors are shorter than the jambs for ease of install when house is heated/cooled by forced-air, that gap acts as a return air path for that room. Otherwise it could help to un-balance the HVAC system. Building inspectors do check for this. Be safe, GBAR
you could put the doors in after the flooring is finished ( un less its carpeting ) your floor guys would appreciate that. Make sure to check the level over the threshold before you cut the jambs.
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.