# Prehung Door Too Tall



## mdjd (Jul 25, 2012)

Hello,

I'm turning a room into a gym and need to install two interior doors to keep the kids out. I'm attempting to use prehung doors in finished openings/walkthroughs that don't currently have doors. It appears the doors are about 1 inch too tall for the opening...door is 81.75" and opening is 80.75". 

The floor is already finished with tile, but I want to lay down 3/4" rubber stall mats, so the current 1 inch gap the prehung door has now is kind of perfect. Are there any other options? Can I raise/cut the top of the door rough opening to allow the door to fit as is? 

Thank you!


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## Nealtw (Jun 22, 2017)

You can check to see if there is a flat 2x4 above the door,and just remove it and maybe stick blocks up in there where it was. 

You do want to remove all the corner beads for the drywall too or your door trim will not lay flat against the wall.


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## chandler48 (Jun 5, 2017)

Removing the sheetrock and corner bead across the top will give you 1/2"+. You may even need the width as Neal suggested. Remove the sheetrock and corner bead all around. Your trim will cover it up.


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## jeffmattero76 (Jan 4, 2016)

Remove the door from the hinges and use a straight edge and a circular saw to cut 1 inch off the bottom of the door (actually I would cut 1 1/4" off so that it doesn't rub on the floor). Then use the circular saw to cut 1 inch off both sides of the bottom of the jamb (again I would cut 1 1/4" off). 

To install it, you would obviously have to remove the baseboard inside the opening, and cut back the baseboard where the door casing will go (I would suggest using a Dremel for that).

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## jeffmattero76 (Jan 4, 2016)

If you haven't bought the doors yet, you could simply buy a 78" door rather than an 80" door. Both are stock items at the big box stores. I believe that a 78 inch prehung door measures 79 3/4".

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## ktownskier (Aug 22, 2018)

You can make the door shorter by cutting it off the bottom. But be careful, some hollow core doors don't have much support in the bottom. 

If after cutting off the bottom, you realize there isn't much left, look at the cut-off portion and peel off the skin, and then separate the sides from the center and then put the center support portion back in the door. Use glue and clamps and maybe a couple of headless pin brads. 

I had to this on a couple of half doors I had to make for a cubby storage.


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## mdjd (Jul 25, 2012)

Nealtw said:


> You can check to see if there is a flat 2x4 above the door,and just remove it and maybe stick blocks up in there where it was.


Just to be sure I understand, what do you mean by adding blocks back to where the 2x4 was? Would the blocks serve as the shim points for the top of the door frame, and therefore the blocks would be cut to the applicable size (Less than the height of the 2x4 I removed)?





jeffmattero76 said:


> If you haven't bought the doors yet, you could simply buy a 78" door rather than an 80" door. Both are stock items at the big box stores. I believe that a 78 inch prehung door measures 79 3/4".



Unfortunately, Home Depot and Lowes stores in my area don't have anything less than 80". Otherwise, that would have worked out quite well...




I'm hoping I can come up with a solution that doesn't require me to trim the bottom of the jambs or the door. I guess I'll attempt to remove the drywall and corner beads first.


Thank you for all the help!


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## jeffmattero76 (Jan 4, 2016)

I am not sure where you are located, but here in suburban Philadelphia, even if the store doesn't have them in stock, they will ship them to your store for free. They cost around $80. Multiple widths are available.

https://www.homedepot.com/p/JELD-WE...rehung-Interior-Door-THDJW136500946/202037304



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## mdjd (Jul 25, 2012)

jeffmattero76 said:


> I am not sure where you are located, but here in suburban Philadelphia, even if the store doesn't have them in stock, they will ship them to your store for free. They cost around $80. Multiple widths are available.
> 
> https://www.homedepot.com/p/JELD-WE...rehung-Interior-Door-THDJW136500946/202037304



I'm in Naples, FL. 



I just called Home Depot and provided all the reference numbers in that link (Store SKU, Internet Number, etc.) and they couldn't find it in their system. I asked if I could custom order it to have it shipped to this store since they don't appear to sell it here and she stated they don't do store to store shipments.


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## Nealtw (Jun 22, 2017)

mdjd said:


> I'm in Naples, FL.
> 
> 
> 
> I just called Home Depot and provided all the reference numbers in that link (Store SKU, Internet Number, etc.) and they couldn't find it in their system. I asked if I could custom order it to have it shipped to this store since they don't appear to sell it here and she stated they don't do store to store shipments.


https://www.napleslumber.com/doors/


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## ront02769 (Nov 28, 2008)

Not what you asked....but yuo realize that those rubber stall Matt’s are going to smell to holy hell for months??


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## jeffmattero76 (Jan 4, 2016)

"I'm hoping I can come up with a solution that doesn't require me to trim the bottom of the jambs or the door. I guess I'll attempt to remove the drywall and corner beads first."


It's your call, but cutting the bottom of the door and jambs is far easier and quicker in my opinion. Should take all of about 30 minutes.

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## mdjd (Jul 25, 2012)

ront02769 said:


> Not what you asked....but yuo realize that those rubber stall Matt’s are going to smell to holy hell for months??



Yes, the strong stench of rubber was pretty brutal the first couple weeks, but it has dissipated quite a bit now...or I'm just used to it. 





So I have a couple more questions before I get started on this today. I do already have the doors, a 28x80 left and right hand of the door in this link.


Actual height: 81.6875
Action width: 29.5625


The current opening is 30" wide, but this is with the finished drywall and corner bead. If (I guess, When...) I remove the corner bead, will I also need to remove the drywall on the inner openings? Just wondering about how much width I can have before needing to step up to a wider door. The door specs state a finish or rough opening width of 30.5625...not sure if this is min/max or just a recommended width. 



Assuming there is 1/2 inch drywall on each side, removing it would put the rough opening at about 31 inches. Unless my math is incorrect, that means I'd have a gap of about .72 inches on each side of the door jambs. Is that too much?


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## jeffmattero76 (Jan 4, 2016)

So that you understand. The reason they call for a 30 1/2" rough opening for a 28" door is that the door (28") plus the jamb on both sides (3/4" + 3/4" = 1 1/2") = 29 1/2". The extra inch that they call for (1/2" each side) is so that you can shim behind the jambs to be plumb and straight. 

Once you install the door, you will likely be installing door casing on the top and sides. Typically that is 2 1/4" wide. Approximately 1/2" of that 2 1/4" will cover part of the jamb (leaving 1/4" reveal). The other 1 3/4" of the casing will hit the wall, and thereby cover the gap between the jamb and the wall.

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## mdjd (Jul 25, 2012)

Thank you for the clarification.


So I would need to put shims in a gap of .72 inches on each side rather than just a 1/2 inch. Is that too big of a gap to shim, or does it not really matter?


If that is too much of a gap to shim, then can I leave the drywall in the rough opening while still removing the corner beads?



Thanks again for all the help!


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## Nealtw (Jun 22, 2017)

mdjd said:


> Thank you for the clarification.
> 
> 
> So I would need to put shims in a gap of .72 inches on each side rather than just a 1/2 inch. Is that too big of a gap to shim, or does it not really matter?
> ...


 Drywall in the opening is fine if you don't need the room for the door.


You do know that the door you order is 2" smaller than the rough opening, door slabs are what are measured but you have to allow for the frame.


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## mdjd (Jul 25, 2012)

Yeah, I initially measured the opening as 30", so I went with the 28" door, already considering that the jambs would add to that width and come in just under the 30" opening. That would leave me a tiny bit of a gap for the shims.


However, since it was recommended to remove the corner beads, I wasn't sure if that could be done without tearing up the drywall that it's attached too (Specifically that inner frame).


If I can remove the corner bead while still leaving the inner drywall, the door/jambs should fit with about a 1/4ish" on each side.


If I remove the drywall because I obliterate it when removing the corner bead, then the jambs will have almost 3/4" on each side to shim. I'm just not sure how big of a gap for the shims is considered too big.


Total wall to wall is 30" (With drywall).


If I remove the drywall, I imagine the measurements would be something like this (adding an extra 1" for removing 1/2" drywall from both sides):


Wall||.72" (Shim) + 29.5625" (Jamb/Door/Jamb) + .72" (Shim)||Wall


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## Nealtw (Jun 22, 2017)

mdjd said:


> Yeah, I initially measured the opening as 30", so I went with the 28" door, already considering that the jambs would add to that width and come in just under the 30" opening. That would leave me a tiny bit of a gap for the shims.
> 
> 
> However, since it was recommended to remove the corner beads, I wasn't sure if that could be done without tearing up the drywall that it's attached too (Specifically that inner frame).
> ...


 If you loose the drywall we just put in plywood an one or both sides to bring close to the 30, If the hinge side is plumb, just screw that side up and shim the other so the top and knob side gaps look good. 

Check the floor for level, if it is out as you have a finished floor, you would want to trim one leg of the frame to fit. You don't want to shim one side up like you might with out a finished floor.


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## mdjd (Jul 25, 2012)

I removed the corner bead as well as the top piece of drywall. The 2x4 at the top is level from side to side, but it's not level from front to back. I imagine that's where the shimming will come into play.


It looks like the door rough is still a bit too short for the door, so I'll go the route of cutting about a 1/4-1/2 inch off each jamb.


Looking at the pictures of the rough opening now, how do you recommend proceeding with regard to the drywall on the sides? Remove and replace with plywood so the gap between the jamb and the rough frame isn't too big?


Also, the floor is level.


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## jeffmattero76 (Jan 4, 2016)

The 2x4 at the top does not matter, since the door is not attached at the top, only the sides.

As stated previously, the casing will cover the gaps. The gaps allow you the room to install shims to plumb the door.

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