Building door jambs Fine Homebuilding Breaktime

building door jambs Fine Homebuilding Breaktime

building door jambs (post #206080)

Interior doors or exterior? (post #206080, reply #1 of 10)

For interior, you can purchase stock jambs and add the stop. Rabbet the sides for the header.

door jambs (post #206080, reply #2 of 10)

IdahoDon’s instructions are good. And like him, I’d say that (post #206080, reply #7 of 10)

How fancy you looking for?  (post #206080, reply #3 of 10)

There are door jamb legs (post #206080, reply #4 of 10)

There are door jamb legs available at any lumber yard — both interior and exterior. The exterior will be kerfed at the door stop for weather stripping and at the bottom youll want to use a ready made threashold, which is usually let into the bottom of the jamb legs (the more common threasholds are also readily available, but if you like a different profile there are what seems like hundreds of options available.

Normally Im looking for 3/32 reveal around the door — 1/8 is too much for an interior door and isnt great on the exterior unless its a clunky steel door, or another with rather crude door dimensions or any door without a bevel on the latch side. 1/16 is just too tight.

On interior doors match the top of your door (actually the lower top portion of the door jamb) to others nearby — it looks funny if doors are slightly different heights and the closer they are the more things have to match. Trim the bottom of the door, or add to it if need be so your height is correct — leaving 1/2 over floor covering (make sure your floor is flat or youll want to figure in the slope of the floor when the door is closed and cut the door to that — most times Ill cut the door 1/4 above a funky floor, install the door, then recut based on an actual measurement when the door is in place).

I use a 32 level to then check the floor to see if one jamb leg will be longer or shorter than the other (on exterior doors everything is normally made square with equal jamb leg lengths).

Make sure the door has straight sides and trim as necessary — dont use an odd shaped door and try to build a jamb for it — it will take 3 times as long. On old doors check for a bevel on the latch side (its a few degrees — just enough so the door doesnt get close to running into the jamb as its opening). If you dont have any bevel, or if the bevel is going the wrong way for its new location, youll have to cut or sand a bevel — a hand held electric plane is the best way to do it, so if you have a lot of wood doors to work on it would be worth at least buying a cheap one.

The top jamb section goes on top of the sides — measure the door width, add 3/16 (3/32 on each side of the door) and add the width of both jambs (normally 3/4ish). For the sides you go from the floor to the lower portion of the upper jamb section — if the floor slopes they will be different lengths. Normally Ill shoot the top jamb to the legs with 10 or so 1-1/2 stapes (1/4 crown) on each side, but you can do just as well with a number of long finish nails, or predrill for 3 or 4 screws on each side.

If you have a previously hung door youll want to deside if you are going to reuse the old hinge positions or start fresh — often its cleaner if you plane off the side of the door enough to remove the hinge mortises and inlet new hinges in the ideal position. I like the traditional 7/11 — from the top of the door to the top of the upper hinge is 7, from the floor to the bottom of the lower hinge is 11, the middle hinge is centered between the two. Id always adjust that to match whats already in the house — sometimes its hard if poor judgment was used originally.

Almost always Ill make a story pole from a 1×2 to layout the hinge locations — I make it for the jamb side so its butted tight to the top of the jamb — and the hinge locations are marked with exact lines — when the story pole is used on the door simply keep the pole 3/32 from the top of the door and mark your lines.

building door jambs Fine Homebuilding Breaktime

If you enjoy using routers now is the perfect time to make a template and route the hinge mortices — if you arent good with a chises but dont have a router, now is the time to practice your chisel skills. Hinges and strike plates should be flush with the wood surface.

Always predrill for hinge screws — even in soft pine where the screw will go in just fine without a hole, it needs it to stay centered in the hinge hole — a scratch awl works great and on hardwood jambs predrill.

You didnt mention if you wanted painted jambs or staingrade, but there is no difference, other than staingrade is much less forgiving since screwups are hard to hide. On paintgrade jambs, I use bondo to fix holes and miscut mortices.

Door stop trim is often installed after the door is in place.

Exterior doors are similar, except make the jamb legs equal and the threashold and top section of jamb are equal. Shim under the threashold as needed. unless its a special case — and there are 100 special cases. The door stop is built into the exterior jamb stock. Jamb length and door height must be considered when adding the threashold — a door sweep is often added to the bottom of the door and must be able to seal against the threashold.

I enjoy building jambs for old doors, but it quickly makes cheap doors rather expensive.

Great sources of cheap doors are habitate ReStores and other thrift stores that take in building materials. Commercial flat slab wood doors (say flat oak doors youd find in a library, school, or whatnot) are thick and perfect for blocking sound from mechanical rooms — even better if its weatherstripped such as for an exterior door — a lot of sound comes around doors.

Beer was created so carpenters wouldnt rule the world.


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