We have been building our own house for many years and now that the main house is finished we are building an addition. In the main part of the house we used pre-hung doors but for the addition we bought some recycled doors without the jamb/casement around them. I’m having a difficult time finding any articles of how to properly build the jambs especially for the exterior ones. Since we live in the mountains of western Colorado and have sever weather issues, it’s important for the doors to be well built and airtight. Would welcome some help.
mjbliss
Replies
Interior doors or exterior?
For interior, you can purchase stock jambs and add the stop. Rabbet the sides for the header.
Exterior jambs are a bit more complicated because you need a beefier jamb. If it was me, I'd buy a manufactured exterior jamb set.
door jambs
Thanks JimB, I agree, the exterior are the complicated ones because of weather issues. Any ideas on manufacturers or somewhere to find instructions for DIY?
IdahoDon's instructions are good. And like him, I'd say that
you just need to go to a real lumber yard to find the jambs. One issue to keep in mind is that the jambs also need to be the correct thickness for the door. Typical thickness is 1.75". I mention this because you refer to recycled doors. I don't know of a good "how to" website, but you could probably find instructions with pictures in a good carpentry book at your library.
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 you'll 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 I'm looking for 3/32" reveal around the door - 1/8" is too much for an interior door and isn't great on the exterior unless it's 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 you'll want to figure in the slope of the floor when the door is closed and cut the door to that - most times I'll 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 - don't 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 (it's a few degrees - just enough so the door doesn't get close to running into the jamb as it's opening). If you don't have any bevel, or if the bevel is going the wrong way for it's new location, you'll 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 3/4"ish). 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 I'll 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 you'll want to deside if you are going to reuse the old hinge positions or start fresh - often it's 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. I'd always adjust that to match what's already in the house - sometimes it's hard if poor judgment was used originally.
Almost always I'll make a story pole from a 1x2 to layout the hinge locations - I make it for the jamb side so it's 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.
If you enjoy using routers now is the perfect time to make a template and route the hinge mortices - if you aren't good with a chises but don't 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 didn't 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 it's 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 you'd find in a library, school, or whatnot) are thick and perfect for blocking sound from mechanical rooms - even better if it's weatherstripped such as for an exterior door - a lot of sound comes around doors.
Be careful with jamb widths - it makes trim much easier or a real pain with every 1/16" - ideally you want to be flush with each side of the wall, but walls are never perfect - or trully plumb, so if you aren't used to trim I'd build one jamb, install and trim it before making more - you'll know why I suggest this after the trim is on.
I'll modifiy the width of the jamb before assembly simply because it cuts down on sanding time - If a piece is added, sanding something flat is 4x as fast as an assembled jamb.
On exterior jambs, you'll want to carefully work through all trim - both interior and exterior - or you'll be sure to be adding jamb extensions and fighting to make everything look right.
Be careful with jamb widths - it makes trim much easier or a real pain with every 1/16" - ideally you want to be flush with each side of the wall, but walls are never perfect - or trully plumb, so if you aren't used to trim I'd build one jamb, install and trim it before making more - you'll know why I suggest this after the trim is on.
I'll modifiy the width of the jamb before assembly simply because it cuts down on sanding time - If a piece is added, sanding something flat is 4x as fast as an assembled jamb.
On exterior jambs, you'll want to carefully work through all trim - both interior and exterior - or you'll be sure to be adding jamb extensions and fighting to make everything look right.
This, Sir, was a useful post.
And I'll offer to buy you a beer so you don't conquer the world. ;-)
Scott.
This winter I built an exterior door jamb from scratch and installed a custom-built door in the opening. I was working on a house that was built in the 1920s but had a solid smooth-faced door that seems to have been installed in the 1960s (judging by the hardware).
To match the other exterior doors of the house, which were original, we had the 7-ft. by 3-ft. door fabricated to our specifications at Stephenson's Millwork Co. in Wilson, NC. The door, which cost about $575 delivered, was 1 3/4-in thick and came unbored and unmortised.
The job can be divided into several distinct stages. I didn't have to worry about a pan or wrapping the RO because the door was well-protected by a porch roof.
The first thing I did was install the sill. Like so many things in old house remodels, this can be done many different ways and you need to size up what the job offers you. On this job, the concrete porch floor had been built up about an inch in the bottom of the doorway, up to the level of the finished hardwood floor. I used an oak saddle to straddle the crack between the concrete and interior hardwood floor. The saddle was about 38-in. long and extended beyond the thickness of the soon-to-be-installed jambs. I positioned the saddle so that the flat part at the top would end up centered under the door. This placement is important later, when weatherstripping the bottom of the door.
Before screwing down the sill, I shifted it over to one side of the RO, then set a piece of the side jamb material on the floor and against the side of the RO. I slid the sill against the jamb and then scribed the profile of the top of the sill onto the jamb. I did this on both sides. Later, I cut the side jambs along these scribe lines and they fit nicely over the sill. Because one edge of the oak needed to go over the concrete, I filled the crack with caulk and then laid a strip of tarpaper over the concrete to separate the concrete from the oak. I used trim screws to install the sill.
The next thing I did was fabricate and install the jamb. For jamb material, I used 5/4 by 6 clear yellow pine. If memory serves, I had to rip the material down to 5-in. width to fit existing wall thickness. After fitting the bottoms of the side jambs as described above, I established a level line across the door opening. I used a laser for this but a four-foot level can also be used. I marked this line about two-thirds of the way up the opening on the interior wall on both sides of the opening. I measured down from the line to find the high side of the sill and then from that side, I measured up 84 1/4-in. from the top of the sill and marked the wall at that level.
I set the side jambs in place over the sills and transferrred the level reference lines to the jams. On the high side, I also tansferred the 84 1/4-in. reference. After taking the side jambs over to my work table, I lined up the level reference marks and clamped the pieces in that position. Then I transferred the 84 1/4-in reference from the one piece to the other. Because the floor wasn't level the distance from the level references to the bottoms of the jambs differed. However, the top jamb would be level.
I laid out and routed a 1-in. wide by 1/4-in. deep rabbit above the top marks. Next I cut a top jamb at 36 5/8-in. Since the jamb would fit into the rabbbit on each side, this would produce an tight opening for the door. Before assembling the jamb, I laid out and routed the mortises for the hinges.
I screwed together the three pieces of the jamb and set it in place over the sill. After confirming that the top was level, I used shims to plumb and attached the hinge side. Once I had the hinge side installed, I set the catch side parallel to it. I won't get into the details of how I fit the door to the opening or how I bored and installed the locksets and deadbolts.
After fitting the door to the opening, I had about an 1/8-in. crack around the sides and top and a tapered space reflecting the unlevel sill below the bottom. I could see light through these cracks. I marked a line on the bottom of the door that was 3/4-in. above and parallel to the top of the sill. After cutting the bottom on this line, I attached a vinyl door bottom and adjusted the height until there was a good, airtight seal yet the door operated well. At the sides and top, I fitted wood door stops with integral weatherstripping. This product is manufactured by Frost King and available at the big boxes. I used finish screws for this, whch allowed me to fine-tune the fit. I was able to unscrew and reattach the stops until I was happy with the way the door operated and how well it was sealed to the weather. I was very happy with the final result, although I left several holes for the painter to fix.