Door Frames or Door Jambs

I am not too sure on the terminology here. I always use the term "door jambs" but by far the most people I meet seem to call them door frames. It is probably more correct to refer to them as frames because the word jamb does indeed refer to only the upright pieces of a door or window frame. So wherever you see the term jamb take it as read that I am talking about the full frame on this page and other pages. Old habits die hard but I,m trying...

On this page.
Frames or Door Jambs | A few examples of what can go wrong when bricking them in. | Typical Layouts | Fixing Timber Frames and Hanging Doors. | French Doors,  | Making and fixing Heavy Doors, | Architraves or Trim around windows and doors.

metal door jambs
Door frames - A stack of metal door jambs ready for the brickie.

Modern steel frame door frames are great, they are stiff and resist bending.   They already have the hinges on.  They are compact to transport and can be easily assembled by semi skilled labour.

A series of tabs in the jambs poke through slots in the head and are belted flat with a hammer.  Spreaders at the bottom keep them at the correct size.

You need to be on the ball with your selections though. When you go to the supplier to pick up the door jambs you need at least this minimum of information.

  • Which hand? left or right opening.
  • How many hinges , two or three.
  • They come in different sizes and qualities.
  • The height and width of the door it fits.
  • They have different frame widths to fit over various thicknesses of walls.
  • Are they being bricked in or fixed to studwork, so what clips are needed?

With stud walls usually it is a carpenter that fixes the door frames. It may or may not be the same guy that fixes the jambs and fixes the doors. Either way, you have a bit more time to get them right than the mad rush when a team of Prima Donna brickies descend on you.

steel door jamb
Door frames - Steel door jamb built into steel stud internal walls

In the above photo the plasterboard flusher has yet to sand.  The metal stays at the bottom will be snipped off by the carpenter when he fixes the doors.

A few examples of what can go wrong when bricking them in.

faults in door jambs
Door frames - what to guard against.

door frames twisted
Door frames - Check for twist, left OK, right one slightly twisted.
  • In the sketch above example "A" is how it should be, nice and true.
  • At "B" the spreader bars at the bottom of the frame have been lost and the brickwork has pushed the bottom in.
  • At "C" the floor is out of level.   If you have the room cut down one leg to get the head level, otherwise pack one up.  The head must be level.
  • In "D" a thin cheap frame has bowed in, most likely the brickie has squeezed a few bricks in tight instead of cutting them.

There is one that I missed in the sketch, that is for wider frames, say for double doors, you must provide support over the top, or in the case of reinforced blockwork, prop the frame to stop the head sagging while the blocks are being laid.

In the sketch at the right, sighting from in to out through the opening, the left frame is perfect, but the other one is twisted.

Most brickies do a good job, read the plans OK and fix the door frames and windows as they go.   If you are an owner builder, keep an eye on them.  If the door jambs are not true, the carpenter is going to squeal.   Probably ask for more money. Correctly fixed jambs mean it is a breeze to fix the doors.

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Typical Layouts

typical timber door frame
Door frames - Timber jamb in timber stud wall.

Above is a sketch of a timber door frame fixed to a timber stud wall. For a brick wall it would be similar, made by the carpenter on the job to suit the wall's finished thickness.

Note the use of broad butt hinges that allow the door to open a full 180 degrees. With standard hinges the door would bind against the architrave.

metal door jamb
Door frames - Metal jamb in timber stud wall.

Here is a metal door frame in a stud wall.   If it was in a brick wall the brickie would build it in as he builds the wall, using wire clips that get hooked into the frame and embedded in the mortar joints.  About four to each side.

Metal frames are simple to fix in stud walls, either steel of timber studwork.   Just make sure you get the opening in the studwork right, as there are different allowances for the various types clips the manufacturers use.

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Fixing Timber Frames and Hanging Doors

Here's a question I have had from Tom (Australia).

I am looking at installing some new external doors to a timber framed house.  I was wondering whether it is better to pre assemble the door frame, pre hang the door in the pre assembled door frame and then install the whole unit at once.   Or is it better to install sill and jambs separately to ensure plumb and hang door last.

Hi Tom,
I am assuming you are hanging timber doors into timber frames.

The way that is normal is to make up your frame in one piece, with the sills and heads nailed or screwed up into the jambs. (I typically pre drill the holes and use 75mm bullet head nails for this, as they grip better in the end grain of the jamb than screws.)

If the job is to be paint finished, paint inside of the joints as well before you put them together. Also paint under the sill if you can, it is never going to get any more paint in it's lifetime.

The doors are usually fixed last, into the already fixed frames, mainly because the frames and outside cladding are fixed by a separate team. The second fix carpenter hangs the doors later. (usually whingeing about the frames being out of plumb etc).

Don't fix down through the sill. These fixings make a potential spot for water to get in. Try to get a fixing from underneath, or if they are standard 820 doors, the fixing to the jambs should be enough with maybe a blob of liquid nails under the sill in the middle.

I have fixed quite a few aluminium doors, which were obviously pre fitted by the manufacture, and they are always easy to fix, because you can see the various aspects of out level, twist, bow in the jambs etc.

So you could do it the pre fitting way if you have a bench to work on Tom.

This could be the best way to go for a first timer.  I'd say pre fit the door with loose pin hinges, then take the door off and fix the frame hanging jamb only, the pop the door on and adjust before fixing it all solid.

I like to use three hinges on outside doors, so I would probably recess my hinges in the hanging jambs first before assembly, but then fix the frames and doors separately, purely because I am comfortable doing it that way.

I always use screws for my frame fixings, that way I can back them out easily and adjust things if it is not right first time.

Also don't forget, paint the bottoms of the doors.

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French Doors

Here's a question from Alex,

Hi Bill - great site and many thanks for your time in creating it.  I was wondering if you had any tips on fitting French doors? My main question is when fitting, I am assuming that door frame is level with floor so nothing to trip on?
Thanks again, Alex

Hi Alex,
Short answer, on a new job, or definitely on a commercial job, make the sill level with the final floor finish. On a refit in a private job, a step over is acceptable.  The French doors I have put in over the last few years have all been pre made aluminium, already hung in their frames.

The reason it is uncommon to see timber framed doors any more, apart from cost, are the requirements of the BCA and local building codes, regarding fixing, glazing and water penetration certification.  I built a high level deck a few years ago, and the access was to be via French doors.   The doors were made by a local joiner who did a beautiful job.   Solid Jarrah with adjustable timber louvres that are rarely seen these days.   I had a heck of a job getting them certified.

The water penetration side of it has meant that the rebates in the frame's sill have gone deeper than they used to be.

Recess in concrete slab for door frames
Door frames - Concrete slab with rebates formed for aluminium door sills.

So, building from scratch, knowing the size of your frame, you can still get the sill just about level with the internal floor finish.  If it is a concrete slab a recess is left in the concrete. As in the photo on the right.

I have recently replaced two sliding doors in my place.  The original door sills were 5mm or so above floor finish.   The new ones are 20mm. I could have chipped the concrete, but as there already is a 120 step between the inside floor and verandah floor levels, I didn't see it as a problem.

If I had to replace my old timber French doors in my old house that had a timber floor, I would do the same, that is let the new frame sit on top of the floor joists and just get used to the slightly higher sill.   I definitely would not chop notches in the floor joists to let the frame sit lower, unless I could beef them up in some way to replace the lost strength.

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Making and fixing Heavy Doors

Here's a question from Rob.

I will be making some doors for my shed. timber Frame sandwiched between ply or OSB sheets (to stop sagging) and hardwood T and G planks (siding) on the exterior. Very heavy. About 1900mm high and 880mm wide each door. (two doors)
  1. the interior frame construction of the door - should be what thickness? I was thinking of 4x2 Spruce or similar dimensions in some other softwood? Comments? I figure that to hang the door I would need about a 4x2's thickness being 38mm minus a mm or so needed to straighten things out. But I can look for thicker wood if you recommend. (I am in Japan so maybe not everything is available) What do you need for fitting most hinges. What is the standard length of screws for heavy duty hinges?
 2. The door frame (or JAM?) - What thickness is normal? I am planing on using hardwood for the door frame. I was thinking of 30mm.(getting expensive) Or could this be reduced to say 24mm or 25mm and just plan on using extra long screws to fix the hinges through the door frame into the studs around the door.? What is normal for a heavy door and what is the normal installation method?
Thanks for any help,


Hi Rob,
Just behind me as I type this in my shed are a pair of solid core timber doors, 900 x 2040 x 42 thick. Fairly heavy. Fixed to a softwood 110 x 32 door jamb. Swung on thick 100mm butt hinges, 3 per door. Fixed with 30mm long screws. Solid as, not moved in the last 8 years.

I have made and fixed similar sized doors out of two layers of 16mm MDF with a 1.2mm lead sheet in the middle for radiology rooms. These were very heavy. From memory I used same sized jambs screws and hinges to swing them. Only I used ball bearing hinges to handle the extra weight. (This type of hinge is used on aluminium and glass doors on shops etc. also very heavy).

I wouldn't use less than 32 thick timber for a door jamb. It is a hassle fixing and keeping straight ex 25 timber.

I'd probably use ex 75 x 35 ( 3 x 1 1/2) internal frames for the doors. 4 x 2 seems a bit overkill, but I don't know how heavy you external boards are going to be.

The strength of the doors will depend on your fixing of the ply or OSB to the frame.


Hi Bill, thanks for the info.  The 4x2 internal frame members are just "4x2" spruce used for house construction.  Actually they are 38mmx89mm.  They are cheap.  I'd say that by the time I planed off a bit to straighten them out they would end up at around about 75x35 as you suggested.  I can check through the timber in the store and get the straightest ones but they nearly always have something that will need to done so they can be used for a frame.
What do reckon for the joints for the internal frame?  Do they need to mortise and tenon or because the racking forces will be taken up by the ply sheeting, would a doweled or screwed lap joint be OK?
OK It sounds like the 30mm jambs should be the go.  and the door will just hang off the jamb.  So I need to secure the jamb to the frame.  What spacing would you say for fixing the jamb to the frame?


Hi Rob,
The joints in internal frame for the door as you say are not all that critical, they are only there to hold it in position until the glue etc. holding the ply takes over. A half lap joint would be excellent.

If you went to the trouble of making lap joints, I'd be tempted to put a couple of braces inside the frame and just sheet the inside with ply and fix you boards directly to the frame on the outside. Save a sheet of ply.

You mentioned mortise and tenon, if you wanted to make the job a definite project, you could make yourself a pair of frame and filled doors.

I would fix the jambs with a pair of screws in four spots, just over your top hinge, just under the bottom and two more sets equally spaced in between.

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Architraves or Trim around windows and doors.

As I said before, we don't do a lot of these now.  They are not needed for steel door frames, and in a house or extension that is using steel frames, you can bet that the windows will have plastered reveals, either plasterboard or solid plaster.

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