# Questions installing custom carved door jambs



## voxhaul (Mar 1, 2015)

Hi Everyone,

I've been renovating my circa 1865 for too many years now and have done most of the work myself (rough carpentry, flooring, electrical, heating, etc.). It has been quite a project. We are getting to trimming the interior, starting with the door jambs, and I have a couple of basic questions.

The original jambs in the house were about 1-1/16" thick and carved from a single piece of wood. In addition to the stop, there is a bead-ish detail on both sides of the doorway where the jamb meets the casing. We have had this jamb stock replicated from a local mill out of 5/4 poplar.

To install the jambs, my plan is as follows: I was going to miter the top jamb section to the sides on a workbench, carry the assembly to the rough opening, align it in the opening with shims, and then nail the jambs into place through the shims. Presto: done!

So my questions are:

- Does this strategy seem reasonable?

- What would be the best way to hold the miters together while fastening the jamb sections together?

- How should I fasten the miters? I was thinking about screwing the corners together? Is there a best type of screw?

- Would 16ga. finish nails be adequate to fasten the jambs to the framing, or should I use something beefier?

Thanks so much for any input. I'm pretty handy, but this jamb project has got me a little intimidated, and I want to do it right!

Dan


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## Ghidrah (Mar 2, 2010)

I wouldn't miter the jambs into the cap, you can rabbit the cap to sit on the jambs then nail or screw through from the top. I don't know how heavy the door is but if it's as old as I suspect it can weigh up to 35-40 lbs. I would also install the hinges and set the door in the jamb to ensure all components square up for an even reveal all around. If it's an int door ensure your jambs extend 3/4" below the door then remove the door. 

Set the frame in the RO and secure it with strapping both sides to prevent it from falling out then install the door. Square it in the opening and shim it snug at the top corners side and top then trim one side, tack trim to wall only. Recheck everything ensure the reveal is consistent then shim down the sides to the floor, ensure you have shims at every hinge and at the striker. Recheck reveal then sink a fin through the jamb. 

With jambs that thick and 1/2" of shims either side you're going to want to use 12 or 16 d fins. All good, the door closes and engages the striker correctly then trim the 2nd side.


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## Steve Neul (Sep 2, 2011)

Probably miter glue and nail would make a good joint but without a picture of the molding it would be hard to say.


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## mako1 (Jan 25, 2014)

Why not attach the head into the sides with a dado like they have been doing for 100's of years?


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## voxhaul (Mar 1, 2015)

Thanks for posting, guys. Ghidrah, thanks for the tips on installation sequence!

I should have been more specific about why I am proposing miter joints for the jamb sections. These jambs are a bit strage in that they are not fully covered by the wall casing. The jamb has a bead detail that extends out beyond the wall and is equal to the front face of the casing. I've attached a picture of the cross section to help illustrate.

It's because of this bead detail that I can't butt the head jamb section onto the sides - the beads needs to join at a 45deg angle.

Given this situation, is there an other option besides a miter? If not, what is the best way to clamp and fasten the miter joints?


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## voxhaul (Mar 1, 2015)

Whoops, forgot to post picture, here it is (attached, I hope).


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## mmwood_1 (Oct 24, 2007)

I don't see a problem with mitering it together before installation. But you will obviously need to set it up square for the mitering, and then you will need to brace it somehow in order to move it without putting too much torque on those joints. It looks like the casing does not overlap the jamb edges at all on the door side, but can you put diagonal bracing across the other side with a screw or nail driven into the portion that the casing will cover on that side? And one piece across at the bottom of the jamb legs? As for attaching the miter joint, once you set it square with glue in the joints, 6d finish nails would do, or some #6 screws, counter-sunk of course.


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## Ghidrah (Mar 2, 2010)

Voxhaul,

1. Do you have any of the original jambs? 
2. Were the original jambs mitered at the corners or did they fit together like a jigsaw puzzle?

Being as old as you suggest odds are the original profiles were cut with molding planes. If so and you're interested it'll take some chisel and handsaw work, the vertical jambs must be cut at a 45 to provide the bead miter then the top cut square so that the beadwork sticks up like prick dog ears. Then the cap bead must be cut/chiseled back to create the 45 miter


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## voxhaul (Mar 1, 2015)

Ghidrah,

YES! I foolishly did not keep any of the many originals that I took out (stupid mistake), but there is one original door with the casing off on one side and you are EXACTLY right about how they did it. The head piece goes over the side pieces, and most of the joint is just a butt joint, but the old guys somehow left the bead detail long on the side pieces when they cut them and they mitered just the beads. I couldn't believe it when I saw it. In fact, we had a friend carpenter looking at this and his reaction was "This joint is... just not possible!"

Was this a common way to join this type of jamb? It seems so labor intensive. I thought about trying to replicate it, but I couldn't think of an easy way to cut the "horns". A full miter joint just seemed so much easier.


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