Interior Door Replacement Issues
#1
Member
Thread Starter
Join Date: Jan 2017
Posts: 3
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Interior Door Replacement Issues
Hi,
My interior door jambs were not undercut, meaning that the orginal owner cut my oak hardwood floors around the doorjambs, and used wood filler to conceal the gaps. The house was built in the 1960's, and I want to replace all the interior doors. I planned on using 6 panel prehung, but am not sure what to do about the "holes" or "gaps" that will exist when I pull out the existing jambs. If I go with prehung, I think my two options are:
1. Fill the gap with a square of oak. I already had to do this for the baseboard trim, because the also installed those before the hardwood floors without leaving a gap for the wood to slide under or undercutting them. When I did this, I was also having all the floors resanded and stained, so the flooring guys ripped thin strips of oak to fill in the gaps (new trim is thinner than 60's trim, so the new baseboard trim would have left a gap if we didn't do this).
2. Replace all of the hardwood in every doorway, so they go under the new jambs.
Or.... Forget prehung, keep the jambs and just get new doors
One other issue. The rough opening is only 80", so I'm guessing I would need either custom prehung or maybe I could cut enough off the frame to fit them in the existing opening. I understand you should have about 2" of buffer in height for shimming.
Any thoughts on the best way forward.
Thanks,
Shawn

My interior door jambs were not undercut, meaning that the orginal owner cut my oak hardwood floors around the doorjambs, and used wood filler to conceal the gaps. The house was built in the 1960's, and I want to replace all the interior doors. I planned on using 6 panel prehung, but am not sure what to do about the "holes" or "gaps" that will exist when I pull out the existing jambs. If I go with prehung, I think my two options are:
1. Fill the gap with a square of oak. I already had to do this for the baseboard trim, because the also installed those before the hardwood floors without leaving a gap for the wood to slide under or undercutting them. When I did this, I was also having all the floors resanded and stained, so the flooring guys ripped thin strips of oak to fill in the gaps (new trim is thinner than 60's trim, so the new baseboard trim would have left a gap if we didn't do this).
2. Replace all of the hardwood in every doorway, so they go under the new jambs.
Or.... Forget prehung, keep the jambs and just get new doors
One other issue. The rough opening is only 80", so I'm guessing I would need either custom prehung or maybe I could cut enough off the frame to fit them in the existing opening. I understand you should have about 2" of buffer in height for shimming.
Any thoughts on the best way forward.
Thanks,
Shawn


#2
You will likely find that your new doors may be a little smaller than your old doors. Measure the distance between jambs at the floor (not including door stop). If it is, say 32 1/4" your new doors will likely cover that "hole" by 1/8" per side.
You will likely have to jamb extend your new doors though. Older doors usually had a wider wall thickness than today's standard doors. Be sure you dont add the jamb extension on the latch/hinge side of the door... do it on the opposite side of the jamb.
On your height, make them as tall as possible... allow maybe 3/8" on top for shims. Your jambs will likely sit on top of the floor... Check your floor for level and if needed, cut each side jamb to match the variation in the floor so that the heads will sit level.
You will likely have to jamb extend your new doors though. Older doors usually had a wider wall thickness than today's standard doors. Be sure you dont add the jamb extension on the latch/hinge side of the door... do it on the opposite side of the jamb.
On your height, make them as tall as possible... allow maybe 3/8" on top for shims. Your jambs will likely sit on top of the floor... Check your floor for level and if needed, cut each side jamb to match the variation in the floor so that the heads will sit level.
#3
Member
To late now but I would have used 1 X 6's and base cap moulding instead of adding those strips.
If your willing to take the time to do this right that flooring that's messed up can be cut out and be replaced.
A prehung door would be at least 5 times faster to install then trying to make a slab fit the opening.
The height is not shimmed so that's not an issue as long as it fits in the hole.
If your willing to take the time to do this right that flooring that's messed up can be cut out and be replaced.
A prehung door would be at least 5 times faster to install then trying to make a slab fit the opening.
The height is not shimmed so that's not an issue as long as it fits in the hole.
#4
I don't see a problem here. My 1950's house looks similar and prehung doors will do the trick.
Just follow X's advice. In the worse case you might need to rip/plane a door down to fit the opening.
Planing the door width and reassembling the prehung frame is still easier than hanging slab doors.
As far as the gaps along the wide walls, that's usually covered with base, plus base shoe if needed.
Just follow X's advice. In the worse case you might need to rip/plane a door down to fit the opening.
Planing the door width and reassembling the prehung frame is still easier than hanging slab doors.
As far as the gaps along the wide walls, that's usually covered with base, plus base shoe if needed.
#5
Member
Thread Starter
Join Date: Jan 2017
Posts: 3
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Thanks for the great replies!
@JoeCaption - I wasn't aware of that 1x6 + cap molding trick, that is a smart solution. The only problem that would have presented, is the base trim would have been thicker than the clam shell molding around the doors. Anyways, the oak strips were a pain, but the end result on that one worked out ok, and I didn't have to do shoe molding which others (not on this board) were telling me to do, but I really don't like the look of. For the shimming, I was referring to extra space I might need to level the header, not the floor. I was just concerned because the opening is exactly 80", and the prehung frames are also 80" (recommend 82" rough), but I suppose I could cut some off the jamb as needed.
@XSleeper - Taking the smallest of 3 width measurements, and 2 on the height gives me an 80 x 32 12/16 rough opening. The distance between jambs at the floor (not including door stop), it is 30 2/16. Based the rough opening measurements, I think I would need to go with a 30 x 80 prehung door. That would leave me with 1/16th on each side. That's pretty close, and if the shimming was off a bit, I could end up offsetting the gap even more on one side. Also, I measured the wall thickness and it's 5 1/4, so it appears I would have to do a thin extension, as the news doors are listed at 4 9/6. I had never heard of that, but good to know
The perfect solution would be to replace all the messed up flooring in all entryways, but that is time consuming and above my confidence level at this point. If you think it's worth it to do that, I will consider it. However, I'm wondering if I could just square off the hole across at the door stop and drop a rectangle cut of oak in there, then sand/stain/filler to blend it?
Thanks again for bearing with my noob questions.
@JoeCaption - I wasn't aware of that 1x6 + cap molding trick, that is a smart solution. The only problem that would have presented, is the base trim would have been thicker than the clam shell molding around the doors. Anyways, the oak strips were a pain, but the end result on that one worked out ok, and I didn't have to do shoe molding which others (not on this board) were telling me to do, but I really don't like the look of. For the shimming, I was referring to extra space I might need to level the header, not the floor. I was just concerned because the opening is exactly 80", and the prehung frames are also 80" (recommend 82" rough), but I suppose I could cut some off the jamb as needed.
@XSleeper - Taking the smallest of 3 width measurements, and 2 on the height gives me an 80 x 32 12/16 rough opening. The distance between jambs at the floor (not including door stop), it is 30 2/16. Based the rough opening measurements, I think I would need to go with a 30 x 80 prehung door. That would leave me with 1/16th on each side. That's pretty close, and if the shimming was off a bit, I could end up offsetting the gap even more on one side. Also, I measured the wall thickness and it's 5 1/4, so it appears I would have to do a thin extension, as the news doors are listed at 4 9/6. I had never heard of that, but good to know
The perfect solution would be to replace all the messed up flooring in all entryways, but that is time consuming and above my confidence level at this point. If you think it's worth it to do that, I will consider it. However, I'm wondering if I could just square off the hole across at the door stop and drop a rectangle cut of oak in there, then sand/stain/filler to blend it?
Thanks again for bearing with my noob questions.

#6
Assuming the jambs will cover most of it, which they will if you center the jambs... you will have a very small area under the door stop to repair. I would certainly NOT suggest making that hole larger... going to all the extra work of cutting out more, which WOULD show. Doing that would be making a mountain out of a mole hill.
#7
Member
Thread Starter
Join Date: Jan 2017
Posts: 3
Upvotes: 0
Received 0 Upvotes
on
0 Posts
Yea, I guess that makes sense. It appears they intentionally offset the jamb, to allow the trim to fit on the right hand side. I guess I will just have to keep their offset, otherwise I'll have two issues. The gap will be worse and then the trim won't fit between the door and the wall.