working with my dad in the past(15+ years ago) i always hated replaced the slab. I know it seems like more work to take the trim, jamb, and door off and out. But when it comes time to level, and plumb, and setup the new door and make it close correctly and sound just right, you know that sound, a nice soft solid closure. It was a nightmare using existing jambs, and new doors.

If you can I'd say replace the whole lot.

 

Each way is a different type of work. If you replace just the slab its cleaner but more tedious work. More measuring and fine tuning and you will more than likely have to shim out hinges. The pre hung will make more dirt as ripping out the old frames and maybe patching walls but once its in its pretty much done.

 

Irish - are you wanting to keep the existing doors or upgrade to 6 panel ?
if you want to build new doors yourself in the future, you can go ahead and square up
the framing and jambs and nail it sound.
then - apply the casework of your choice and finish the baseboards and build the doors
later down the line when you get your tools set up.
once the door frames and jambs are square and secure, any replacement door will (should) fit
with very little trimming. all doors are not always the to the same code when it comes
to knuckleheads doing the install.
it will be worth your while to invest in a Door Lock Hole Saw Kit and a hinge mortise kit for your router.

The house that I bought last year was a rental for the past 25 years and the doors have
probably been changed a few times during that period. when the seller decided to sell it,
he put in cheap 6 panel hollow doors that are stupidly installed just to pass inspection.
and also put in cheap carpet over pine hardwood floors. now - I have to replace 7 inside doors
and more than likely put in new hardwood floors if these are not salvageable (it is a 1957 house).
so - in home ownership, you have to arrange your priorities according to your time and budget.
the gap under the doors you show was probably for thick carpet floors. for hardwood or tile floors,
it is much smaller - like maybe a half inch or so.

good luck in your new digs !!

Note: on the subject of installing slab doors; the bottom internal board is only a fiberboard maybe one
or one and a half inch tall. so if you need to cut much off the bottom of a door, insert a putty knife
under the skin to loosen the glue grip and drive the wood strip deeper into the door body with a block of wood
and apply new glue; then trim as needed.
if you have to cut 1" or more off the bottom of a door, you may run out of "meat" for the bottom.
and my house is 61 years old ~ there is no telling what obstacles lay ahead in the reno.

.

.

 

Thanks for the responses guys! John, I don't have the time to build doors and my shop is under construction, so buying Solid Core MDF 5 panel shaker doors is the only option. I think I'm leaning towards just buying the pre-hung, that way I just have to square up the door frame to the jam and I'm done, fingers crossed. The extra work to make a slab door work is starting to look like a pandora's box of what if.

 

I don't know why you'd buy pre-hung except for new construction. I built new doors for my house and just mortised for the hinges, drilled for the lock set and I was all set. Your openings should be a whole number, like 30", 36" etc. The slab you buy will be 1/4" narrower. If it's a little off - and good luck finding a house that's perfectly framed and square - you can use a plane to trim the slab. They all have solid wood around the perimeter. I used a 3-1/4" electric hand planer on the couple of mine that rubbed a little.

You can see some of my doors here:

http://lumberjocks.com/projects/342593

http://lumberjocks.com/projects/336337

http://lumberjocks.com/projects/300378

 

Beautiful work on the doors Rich. So, I guess if I went for slab doors I could shim the jams as needed since the casings are off and go from there. Justin, the first response, described exactly what I am fearful of, fussing with solid core slab doors to make them plumb, messing with reveals, scribing to fit and making sure the door closes correctly. I have tons of patience when it comes to stuff like that but if it can be avoided by going the pre-hung route then sign me up.

Oh and of course it needed to be done yesterday!!!!

 

Pre hung on old work is just a lazy mans way of doing things in my mind. Take the time and make the old stuff work. I hate that today's society is all about disposable one time use and discard. Plus non pre hung will probably be a lot less expensive anyway.
Sorry if I sound like a grumpy old fart….well I am!

 

I'm a lazy man. I would go with new pre hung and not mess with lining up hinges and strike plates.
Slap em in and done!

 

I've never run into the nightmare scenarios you guys are describing. Like I said, the openings should be pretty standard. At the store when you buy a 30" slab, it's actually 29-3/4" to allow for a 1/8" reveal. That's standard. If the hinges are properly mortised into the existing jamb, then all you have to do is make sure you mortise them correctly in your slab.

There are variables regarding the hinges of course. Mine are 3-1/2" with a 5/8" radius. Yours might be something else, like 4" with a 1/4" radius, or even square. If yours are either 1/4" or square, then I'd recommend building your own jig, since a 1/2" bit will give you that radius, and you can square it with a chisel if it's square. The 5/8" radius is trickier and I bought a jig from Woodhaven for it for about $25 that's worked perfectly.

The trick to setting the depth for the mortise with a plunge router is to get the jig in position, put the router on it and bottom the bit out onto the door slab, then take a hinge and put it on the plunge stop, lock down the stop and then when you remove the hinge and plunge it'll stop at a depth that is exactly the thickness of the hinge.

I'll be happy to answer any questions that come up as you go along. Post them here or PM me.

Now, all that said, you could have the house from hell where it doesn't just drop in like it should. You can check for that though before you go shopping. Measure the width of the opening at the top, bottom and near the strike plate. If they're within an eighth of an inch or so you're OK. It should also be a whole number, like 28, 30, 36, etc, inches wide. If it's off more than an eighth of an inch or so, you're going to be trimming. If it's a little over, that's no big deal, you just have a larger reveal that no one will notice. Also, take a framing square and see that the corners are square, or close to it. If all of those things look OK, then you'll have no trouble at all.

Oh, one last thing. It's pretty critical that the hinge mortises are cut at the proper location. I made a story stick based on the existing hinge mortises in the door frame and used that to mark the door. Also, on an interior door, the standard setback for the hinge from the face of the door is 1/4". That's pretty critical, if you miss it too far either your door will stick out from the frame, or it won't close.

 

Thanks for your help Rich, I really appreciate your detailed replies. Story sticks are perfect for this application and making a jig for the hinges is a critical.

I measured my openings and they are mostly within 1/8'' of the needed opening with a few spots over by 1/4+ or -,
The framing square tells me that nothing is square but no surprise there. I guess the question is how badly out of square is it and can I help square up the jam since the casing is off. I guess I should measure the opening like I'm squaring up a drawer box. The door stop should hide most of the out of square settling huh?

 

Pre hung.

 

no question about it, prehung doors, you can have them prehung with correct space under door, just remember if you do not have a ac transfer duct to equalize room once door is closed a minimum of 3/4'' is needed to accomplish this.

I'm in the const. biz, and while your time may not be a cost factor for you, we pull doors and jambs and re set new prehung units that beat the cost of rehanging new slabs. you can specify prehungs with three hinges, ect. and so many options of door types and styles, solid core for a more quiet room, and nicer close. hollow core for cost factor.

good luck, remember to shim jamb at bottom of jamb, lots of door hangers don't do this, but its a must for me, have to teach all the new guys to shim doors correctly, once done they will be set for ever with no issues.

Rj in az.

 

no question about it, prehung doors, you can have them prehung with correct space under door, just remember if you do not have a ac transfer duct to equalize room once door is closed a minimum of 3/4 is needed to accomplish this.

I m in the const. biz, and while your time may not be a cost factor for you, we pull doors and jambs and re set new prehung units that beat the cost of rehanging new slabs. you can specify prehungs with three hinges, ect. and so many options of door types and styles, solid core for a more quiet room, and nicer close. hollow core for cost factor.

- Knockonit

I know you're a pro and I respect your opinion, but I think the keyword for you is that you're in construction. If you're talking about new construction or a remodel, then yeah, pre-hung is a no-brainer. However, in an existing doorway I can hang a slab door in under 30 minutes. I make a story stick for the mortises, rout them in the door, hang the door and drill for the lockset. If I had one of those fancy mortise jigs that you set to the jamb and then put on the door and rout, I could probably knock it down to 15 minutes. I've done so many I don't even think about it.

I don't see the advantage of tearing out perfectly good trim, shimming, etc, and then replacing trim that needs to be mitered and painted. Also, unless you're repainting the entire room, good luck getting your fresh trim to match the existing paint.

 

I am definitely not one to waste material and rip out things unnecessarily but I think I am going to go pre hung.. Got prices, on the same style door, this weekend from HD and my local Mom and Pop hardware store, both selling slab only for $150, prehung for $220. Lowes is selling same style solid core MDF door pre hung with only 2 hinges for $150. So, I could get the all machine prep work and hinge costs done on the doors for the same price as a slab door. Sound true good to believe? They are Reliabilt doors by ABS.

Would like there to be a 3rd hinge on the Lowes door and cant find out if the jams are wood or MDF but otherwise it seems like a good deal. Without buying all 3, who knows how different a solid core MDF door could be.

Is there a rule of thumb that the pre hung doors should be installed 48 hrs after delivery? I won't have any help on this project and it make take me 1 or 2 weeks to get them all installed.

Thoughts on this gentlemen?

 

I have put in both and if the jamb is okay and the trim, I would always hang a slab.I cut the door to fit with the clearances I want, shim it up in the opening and then scribe the hinge locations to the door and I have made a door hinge fixture for my router base that cuts perfect 3 1/2" hinge mortises. You have to transfer the lock hole but that is pretty simple, too, and you can make a perfect alignment if the house settled a bit

Cheers, Jim

 

Prehung for sure!

 

no question about it, prehung doors, you can have them prehung with correct space under door, just remember if you do not have a ac transfer duct to equalize room once door is closed a minimum of 3/4 is needed to accomplish this.

I m in the const. biz, and while your time may not be a cost factor for you, we pull doors and jambs and re set new prehung units that beat the cost of rehanging new slabs. you can specify prehungs with three hinges, ect. and so many options of door types and styles, solid core for a more quiet room, and nicer close. hollow core for cost factor.

good luck, remember to shim jamb at bottom of jamb, lots of door hangers don t do this, but its a must for me, have to teach all the new guys to shim doors correctly, once done they will be set for ever with no issues.

Rj in az.

- Knockonit

Agree Completely! Why mess with the Older Stuff, refit etc. You're going to have to do some Repainting anyway to make it all Match. The new doors don't present any kind of a problem with the new Jambs & Casings.

I've done it MANY Times!

Rick

 

I would very much suggest replacing the whole thing. If not ur stuck with someone else's mistakes. If you replace the whole thing you'll probably b more satisfied with the finished product
Also I feel ur pain. I moved last year and had to replace 6 doors. I actually still have 1 more to do I'm just lazy.

 

I decided to go prehung guys. Ordered nine doors from Lowe's got a pretty good price should be here in 2 weeks. One of my concerns is that since we already have our new floors installed my rough openings are 81.5 " tall. So I believe I'm going to have to level and cut all the jambs down and then probably remove 1/2 to 3/4 inch off the bottom of the doors so they have adequate air gap.

I'm thinking I should put a level on the floor at the bottom of the opening and shim until level, measure thickness and then remove that amount from opposite jamb leg.

Anybody have any advice on installing prehung Doors in an existing house with new flooring installed and 81" rough opening heights?

Oh and has anyone ever used the prehung wall brackets where you strike a Plumb line on both sides of the jamb and then adjust the metal brackets till everything's nice and square?

 

Never knew about the brackets till I got most my doors hung. That being said if u work alone they look like they'd b wonderful. Lol.