Door Jamb Construction and Installation

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Forum topic by Evanston posted 04-11-2018 03:54 PM 597 views 0 times favorited 7 replies Add to Favorites Watch
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6 posts in 931 days

04-11-2018 03:54 PM

Topic tags/keywords: doors

I’ve been lurking on this site for quite a while, gleaning a ton of useful information from the members’ collective experience – much appreciated – but I have some questions about door jambs that I thought someone might be able to help with. I apologize in advance if this is not the type of question that is generally appropriate for this forum.

I’m replacing all of the painted woodwork (baseboards, crown molding, door jambs/casings/trim) in my 1925 bungalow with red oak that will be stained. I tried stripping the existing wood but most of it turned out to be not stain quality wood, hence my project to replace all of it. I’m about to start building 6 interior door jambs and I’m not exactly sure what the best approach for building new door jambs is.

Question #1:
I kept all of the old jambs to use as references as I build new ones and they were all constructed with dadoes on the side jambs for the head jamb. Here’s a pic:

Most of the examples of constructing door jambs I’ve found elsewhere simply cut the head jamb to size and screw or nail it in either from the sides or from the top. I would think the dadoes would add more strength and stability to the jamb and they would be easy to route. I kept the woodwork in the kitchen (birch) so I’d like the rest of the house to be consistent, but I’m not a total stickler for historical accuracy. Is this a good method to use, or is it total overkill?

Question #2:
The side jambs were shimmed and nailed with 2 1/2” nails (not sure the exact nail size), but not the head jamb. There were 5-6 sets of 3 nails spaced along the hinge jamb and 3-4 on the strike jamb, and for each set of nails one is located underneath the door stop and the other two were nailed from the sides of the jamb into the stud. (I have pics if this doesn’t make sense.) Apparently they did this so no nails showed on the visible portion of the jamb, but since the jamb is only a tad over 3/4” there were numerous spots where the wood split, most of which were covered by the casing. This method apparently worked ok since the house is over 90 years old and I hadn’t had any problems with the doors in the 12+ years I’ve owned it.

I’ve got a 16g Bostitch nail gun with a 2 1/2” max capacity that I was hoping to use to attach the jambs – will this be a big enough nail or should I bite the bullet and get a 15g? I’m not going to nail from the side as they did originally, so I want the visible nail holes on the jamb to be as inconspicuous as possible. I should mention that the doors are solid, not hollow core. My gut tells me 16g may not be strong enough, but I was hoping not to buy another nail gun since I already have a 16g, 18g and 23g!


-- Measure five times, cut once, curse a bit, get a new piece of wood

7 replies so far

View Loren's profile (online now)


10719 posts in 4532 days

#1 posted 04-11-2018 05:37 PM

I’d call the dado overkill but there’s no harm
in it if you want to do it. It would make lining
the header up perfect easier. Pre-milled jamb
stock often has a rabbet in the two top ends.

I wouldn’t be worried about the 16 ga. nails.
I use a 15 ga. nailer but the main reasons are
the steeper collation angle and the rounder
nail heads which make the nail holes look more
like regular nails, not strength.

View jerryminer's profile


960 posts in 2326 days

#2 posted 04-11-2018 06:30 PM

I agree that the dado is overkill but not harmful. I typically use a rabbet.

16 ga. nailer is fine, but I would add some screws to the hinge side jamb—this can be done behind the hinge leaf, or with a long color-matched screw through the hinge itself.

-- Jerry, making sawdust professionally since 1976

View Evanston's profile


6 posts in 931 days

#3 posted 04-11-2018 07:07 PM

Thanks to Loren and Jerry – I was pretty sure the dado wasn’t really necessary. As to the nails, I may use regular 8d nails under the door stop and 16g alongside them. Screws under the hinges are another tip I’ve read elsewhere as well. The hinges are Satin Nickel and a quick search turned up 3” steel screws with that finish for about $10 for 24. Not cheap, but I don’t need that many. I haven’t ruled out getting a 15g nailer since two rooms will have some rather beefy crown molding to install and the angle would be helpful, but I’m not too keen about the larger size of the nail holes on the jambs.

-- Measure five times, cut once, curse a bit, get a new piece of wood

View va_scubadiver's profile


10 posts in 3749 days

#4 posted 04-11-2018 07:25 PM

My dad built houses through the 60’s and I’ve done a fair amount of work in older homes as well as running a door and cabinet shop in the early 80’s. The dado was very common and I still use it when I build a jamb from scratch. It allows for some movement in the width of the jamb stock without a crack developing between jamb and header. I will typically build up the jamb without a door stop – starting with 1x ripped to width, mortise the hinges in (I use a 40 year old Milwaukee template kit), assemble the jamb, nail the casing to the side the door is on, install the door in the rough opening – shim at hinges, floor, header and above and below strike plate, nail through the jamb at the centerline of where the door stop will be installed, then pin nail the door stop over the nail heads. Nail on the casing on the remaining side…

While the dado may be considered overkill – it is a good practice I think.

-- "Slow work takes time..." - Martin Breen

View Evanston's profile


6 posts in 931 days

#5 posted 04-11-2018 07:47 PM

Scuba, thanks for details on your process for jambs. I’ve not built jambs before so the steps you go through will be really helpful, plus they just make sense from what I’ve read about jambs and looking at how my old ones were made. I did say the dado wasn’t necessary, but I actually kind of like the idea of making the jambs the same way they were made in 1925. I’ll recheck, but I’m pretty sure they didn’t shim the head jamb to the stud header – too much room to fill.

Have you ever seen in the old homes you’ve worked on the jambs nailed at an angle from the side into the stud? I’m not sure I want to try that, but it did allow the jambs to be free of visible nail holes and it would probably be easier with a nail gun than hand driving a nail.

-- Measure five times, cut once, curse a bit, get a new piece of wood

View Klondikecraftsman's profile


52 posts in 937 days

#6 posted 04-11-2018 08:23 PM

If you think your nails will be too light even with the screws, predrill your new door jambs and put finish nails under the door stop.

-- It is a sin to covet your neighbor’s wife, but his woodpile is fair game.

View Evanston's profile


6 posts in 931 days

#7 posted 04-12-2018 01:03 PM

Thanks to all for the responses and good ideas. As much as I like to have an excuse to buy a new tool, I’m going to use my 16g, along with long hinge screws and 8d nails under the door stop. I’m going to start with one of the closet openings and see how it goes…

-- Measure five times, cut once, curse a bit, get a new piece of wood

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