Mahogany Door Jamb - What nails and where?
I am installing sapele mahogany 3/4" thick door jambs & casings and 1-3/4" thick doors in my house (not prehung) on 4-1/2" thick walls (3-1/2" studs + 1/2" drywall on each side). I am pretty clear on the process except for nailing the jambs.
But I am unsure as to where to put place the finish nails into the jambs except for that they should be below the shims. Some articles I read say to nail sets of two nails horizontally just below each shim location such that the door stop will cover them. Others say to nail sets of two nails horizontally at each location seemingly a few inches apart. This seems to make more sense since although I would be using shims along the jamb, having the nails farther apart would seem to make the jamb more stable than nailng the two nails closer together. But that would mean the door stop could only cover one of them maybe. Then I would have to countersink the nail that is showing and try to match a wood filler to the mahogany. I am concerned because these are sapele mahogany jambs with a clear coat finish rather than something I am going to paint so I want as few nails to show as possible. I know that I will have to nail the door stop to the jamb but that will be with thinner shorter nails and so it will be easier to hide the countersunk nail (same with the casing).
Another method I heard of is zig zag about 8-10 finish nails along the length of the doorstop so they will be hidden by it (making sure I guess that there is at least one beside each shim).
Any advice? The articles I have read don't seem to be to clear about this aspect of installation.
Many different ways to do it. All will work
I have always installed jambs using a minimum of three sets of two nails into each leg with the pair of nails going through the lower edge of the shims spaced about 3"" - 3 1/2 inches apart. This keeps the jamb from moving when the door, especially a solid core door, is opened and closed. Since you have prefinished jambs you might want to try a single nail behind the stop moulding if you think the casing strong enough to hold the jamb in place. I don't know if that will hold up for a door used often but you might want to test it out. Generally, doors swing into the room and so you do not see the jambs on closet doors unless you open the door. Good Luck.
I don't know if that would be strong enough as I have never done this before. It just seems to me that nails place in the 1-1/2" width space of the door stop might not be enough to stop the jamb from rotating about the center, but then the shims will help stop that rotation. The casing is 3/4" thick flat mahogany (ie not traditional) and I guess I will be putting finish nails through it into the jamb and and also into the stud but I don't know if this is enough. I just want to have as few visible holes that I have to fill as possible.
These are bedroom, bathroom and hall doors. I was hoping someone with experience doing this would know.
Shim your jamb behind all the hinge areas (at least 3 per side even if there is no hinge in the middle), a couple over the head, and in three places on the strike side including a shim behind the strike. You can try to hide all your nails behind the stop. The casing should keep the jamb from twisting if it is nailed securely. Cut off the protruding shims with a Japanese trim saw (can't think of the name of it right now) or any fine tooth finish hand saw.
Thank you Wallace49.
I am going to have 3 hinges as these are heavy doors and I don't want to gamble. I was going to put at least 3 sets of shims at the hinge locations, but have read that for the top hinge it is better to put the shim just below the hinge, substitute one screw of the hinge (the centre one) for a longer screw that would go right through the jamb and into the stud, thereby having the ability to tighten that screw and adjust the top of the jamb if it should bow slightly into the opening when the heavy solid core door is installed. Advisable?
Also, some say at the other shim locations don't put any nails into the shims, but just below or above the shims, as the shims could split and fall apart if the nails are driven through them, some say use plastic shims as they won't split, some say nothing. So, I am confused as to which is the best method (it would seem if nailing through the shims is advisable then plastic shims are the best to use, no?)
Also, just to through more fuel into the debate, someone suggested to me to use screws instead of nails to secure the jamb. Screws have better holding power than nails so this seems to make sense. But, am I right in saying that trim carpenters don't use screws because it might be both overkill and is also very labour intensive compared to a finish nail gun?
One other issue that seems to come up. Some say to fasten the head jamb to the side jambs before installation. Some say to do that with dado's or rabbets, not just butting them together, and glue and nail them together and then some just say to put them all in separately. Then some say just put the head jamb in first and then the side jambs. Which is the best method for these different aspects of the jamb installation?
For exterior doors I always use a long screw through the hinge, as this is a heavy door you may wish to do the same. Finish nails will work fine, screws through the jamb in place of nails will not have a benefit that is great enough to make up for the additional finish work. Head should be in a dado with screws holding the jamb together. When I do not purchase a prehung door I hang it into the jamb on a workbench as it is easier to hang and I get a better job. I always glue my jambs (at the dado), and glue the casings at the mitres or plinth blocks. If you are using 3/4 stock for the casing biscuits are worth the extra work.
Actually I just measured the jambs and casing and they are 7/8" thick, not 3/4".
I was wondering why biscuits are a good idea for the casing with the thickness I am using. Can you elaborate? Wouldn't they be advisable for any thickness if the joint separating is the issue?
Also, your suggestion to hang the door on the jamb on the workbench seems like a great idea. But I am confused about the actual process and have researched this on the net and haven't found a comprehensive description yet. Correct me if I am wrong but I outlined the steps I feel I must go through in order to do this properly. I bolded and italicized some of the questions I had. But let me know how you do it if I am totally off base or differ from your procedure anywhere, if you would be so kind. It's tough for a newbie like me and I really like to do things right by using best practices (sorry there are many steps it seems to do it right):
1. I am going to use 3 hinges as these are solid core doors. Mark hinge locations on the door (7" to top of top hinge, 11" to bottom of bottom hinge and centre the 3rd hinge between the other two).
2. Route out the mortises for the hinges on the door;
3. Install the hinges on the door;
4. Check to make sure the floor is level from one jamb to the other at the threshold of the rough opening and also from front to back of the jamb (if not the hinge and strike jambs must be cut to slightly different lengths and possibly the bottoms at different angles so that the top of head jamb is level and the bottom of the jambs rest firmly on the floor).
5. Cut the hinge and strike jambs to length, in my case about 1-3/4" longer than the door height in order to allow for a 7/8" dado width (for the 7/8" thick stock I am using) + 1/4" (or more?) of material to the end of the top of the jamb + 1/8" head jamb clearance (ie between the head jamb dado and the top of the door) + 1/2" clearance between the bottom of the door and the floor (which is already finished everywhere);
6. Router dados into the hinge and strike jambs 1/2" deep (would 1/2" deep be suggested for my 7/8" stock?) such that the top of the dado is 1/4" from the top end. (Actually I guess 6. could be done first then 5?);
7. Lay the hinge jamb flat on the door, leaving 1/8th inch between the top of the door and the bottom of the dado and 1/2" from the bottom of the door to the bottom end of the jamb;
8. Mark the hinge locations on the face of the hinge jamb. Mark the other face of the hinge jamb 'STUD SIDE';
9. Route out the mortices on the hinge jamb;
10. Cut the head jamb so that the distance between the strike and hinge jambs is 3/16" wider than the door (1/16" to allow for the hinge and 1/8" between the door and the strike jamb). I am not painting the doors but just using a clear coat finish so I think 3/16" total is adequate (or should I use 1/8" or ?). So, if the dado is 1/2" deep on each side then the head jamb should be 1/2"+1/2"+3/16" = 1-3/16" wider than the door. The edges of my doors were bevelled at the factory, so thankfully I don't have to do that;
11. Fasten the head jamb to the hinge and strike jambs using wood glue and drive 3 x 15g finish nails horizontally from the outside of the hinge and strike jambs into the ends of the head jamb;
12. Now this part I am not sure about. Do you hang the door on the jambs while the jamb assembly is horizontal on the workbench? ie. Do you lay jamb assembly, hinge side up, on the workbench and then lay the door inside the jambs on top of some wood such that the face of the door is flush with the edge of the jambs and install the hinge pin and recheck that there are all the proper clearances mentioned above?
13. Tack a piece of wood as a spreader between the hinge and strike jamb legs to maintain the distance between them when you install the jamb assembly;
14. Take the pins out of the hinges, and remove the door;
15. Install the jamb assembly into the rough opening with shims below or behind (which?) each hinge (so 3 on the hinge side), 3 on the strike side with one being behind where the strike plate will be and 3 on the head jamb (each end and the center) all using tack nails (ie 2-1/2" 15g finish nails driven through the jamb and partially into the studs) along the centre line of where the door stop will be (so the door stop will cover them) until everything is perfectly plumb and square;
16. Hang the door now or wait until after 16?;
17. Drive the tack nails fully into the studs;
18. Shoot a single 2-1/2" 15g finish nail in through each shim or just below the shim location along the centerline of where the door stop will be installed so that they will be hidden (through the shim or just below? Apparently shooting them through wood shims can split them but if you use plastic shims they won't. Also, if you shoot them below the shim location at the top hinge then adjustments can more easily be made as in I've described in #20). Some suggest screws have better holding power but this might be overkill but maybe since I am only using a single one I should use a screw. But, 15g finish nails have also been suggested as being more than adequate. And this might be especially true since in my case I have 7/8 thick casing being nailed into 7/8" thick jambs. Since the head of the fastener into the jamb will be hidden by the door stop I don't care about the appearance of the head of the screw or nail. But driving screws is definitely more labour intensive if I use screws everywhere. I just might try nails everywhere but use screws in one location just to see what happens over time;
19. Hang the door now? (take off the spreader as required to install the door)
20. With the door hung make sure the top of the hinge side jamb hasn't bowed in slightly. If so, replace the centre screw of the top hinge with a long screw that goes through into the stud and tighten it a bit to eliminate the bow. Also, if a matching screw colour and head cannot be found then a non-matching screw can be installed behind the hinge.
21. Install door stop using 1-1/4" 16g finish nails (1/2 thick door stop + 7/8" thick jamb = 1-3/8" total thickness but I guess 1-1/2" or even longer can be used as it does not matter if the nail goes into the stud)
22. Drill holes for the cylinder door handle/lock (or should this have been done before the door was hung?);
23. Mark and install for strike plate;
24. Install door handle/lock;
25. Install casing using 2" x 15g finish nails through casing at jamb (since with 7/8" thick casing the nail will go 1-1/8" into the jamb) and spaced 16" apart (less/more?), 2-1/2" x 16g finish nails through casing at drywall (7/8" thick casing + 1/2" thick drywall leaves 1-1/8" into stud) and use biscuits with glue at mitred corners;
26. Countersink all nails and fill all holes with matching putty;
27. Finish the door assembly with the clear coat.
You were on a roll until you got to #14. I usually leave the door hung in the jamb when I set it. That way you can see the reveals around the door as you nail off the jamb. This can be a little bit of a balancing act before you get the first hinge nailed off. With the door in the jamb it also lets you check the "cross-site" of the door. Cross siting the door assures that the top and bottom of the door make contact with the door stop at the same time. You can nail through the shims and it will actually help keep them in place until you are ready to cut them off. I use thin wood shingle type shims, and place them behind the hinges. If you have checked the floor for level and made any cuts needed on the jamb legs to make the head of the jamb level then all you need to do now is get the hinge side plumb and the strike side will follow. Of course you still need to shim the strike side the way you planned and check your reveals and cross site as you go. Another tip is to nail off the casing legs and head onto the hinge side of the door jamb (with the door in the jamb) and slip the assembly into the opening. You can then check the hinge side for plumb and nail off the casing near the top hinge first to get the door steady in the opening. Then making sure the hinge side is plumb nail it off through the casing. You can then shim the jamb from the other side and nail it off and then do the same on the strike side. Cut protruding shims off with a fine tooth handsaw, and case out the other side. When you cut the shims hold your saw perpedicular to the protruding shim and cut from the jamb toward the drywall. This way you will not score the jamb with errant saw marks. Nail your casing miters together from the top with a small brad nail to keep them tight. Doesn't hurt to glue the miters as well. After you do all this you can replace a screw or two on the hinges with longer screws that will reach through the shims and into the stud. Don't crank them down too hard or you can move things around. Hope this helps. :thumbsup:
Thanks. A few questions:
A. When cross-siting I am checking to make sure the face of the door is in exactly the same plane as all 3 jambs right? I assume I don't have to have the door stop installed when I do this since as long as the door stop is installed parallel to the face of the door at the right distance from the jamb face, the door will make contact with it at the same place along it's entire face.
B. I don't know what you mean by 'nail off the casing legs and head onto the hinge side of the door jamb (with the door in the jamb) and slip the assembly into the opening'. Are you saying to nail the actual hinge side casing and head casing on the hinge side onto the door before placing the jamb/door assembly into the opening? That would mean I could not stick the shims through both sides into the gap between the jamb and stud because the casing would be in the way, if I understand you correctly. Wouldn't that make it hard to adjust the shims so that the jamb was plumb and square to the wall? Maybe I don't understand what you are saying. Please elaborate.
C. If I leave the door in the jamb assembly, even with a 26" wide (the narrowest of the ones I am hanging) x 1-3/4" solid core door it will be pretty heavy so I guess I would need a helper (but then I've been going to the gym a lot lately, lol). Or is this something that can be done by myself?
D. I was advised above to use biscuits to fasten the mitres together. Are small brads just as good?
And I do actually have one of those Japanese flush cut saws, called a kugihik, which I got from Lee Valley Tools here in Canada (great company btw for many tools and garden stuff - they do online orders), which I used to cut off the plugs on the exterior sapele mahogany siding I did before. Thanks for the tip to remember to cut away from the jamb but I also have to remember to use the proper side of the saw as the teeth are very slightly bent upwards on one side to avoid scratching any surface (more important on a deck or siding).
If you find that you do need to use screws for the jambs, you can use scraps of the jamb stock and a plug cutter to hide them.
I'll answer your questions in order. I'm assuming these are interior doors you are installing.
A: When you cross sight a door you are making sure that both legs of the jamb are parallel to each other so that the door closes flush with the edge of the jamb all the way around. If your wall framing is slightly out of plumb on one side or the other and you just line up the jamb along the walls on both sides the door will be "out of cross sight". I usually try to move the wall at the bottom plate to line up the two sides if the cross sight is way out. If you have the door stop installed the same distance from the edge of the jamb top to bottom on the strike side and your door touches the stop top to bottom at the same time then you have your door cross sighted correctly. Sometimes if nudging the wall is not an option you can move the bottom of the strike side of the jamb to bring it parallel with the hinge side. Also, if you have the door stop already attached to the jamb it can keep the door from swinging through and tweaking the hinges.
B: Nailing the casing onto the hinge side of the jamb and fastening the miters with glue and biscuits or glue and brad nails allows you to push the door into the opening without it falling through the other side. You can then plumb the hinge side and put a few nails through the casing into the wall to hold the door in place while you make all your other adjustments. To shim the jamb just put the thick end of the shim in first and then the thin end of the shim bumping against the inside of the casing. Keep doing this until you have filled the gap and then nail through the jamb to hold it all in place. then you just need to trim the shims on the one uncased side. This is a tried and true method used for decades that allows for faster and more efficient door installations. I have no idea how many doors I've installed using this method, but it is in the thousands.
C: If you use the method just described you will find it much easier to hold the door and jamb up against the rough opening without it tilting through the other side. It will help you to control the weight of the door.
D: Some casings are beefy enough to use a biscuit in the miters and it works well, but you can glue and nail them together as well. Check your miters after installation to make sure they are all tight.
I know it's politically incorrect but we call them "Jap Saws" in my neck of the woods. They are great tools and cut on the back stroke.
Thanks. I understand now. And these are all interior doors. A few more questions if I may:
You seemed to suggest that I also attach the door stop to the jambs before installing the unit. Since I want to shoot the nails along the centreline of the door stop so that they will be covered when I install the door stop this is not really possible. Would tacking the doorstop on the strike side (or just a partial length of door stop), such that I could remove it later to install the strike side jamb first, be a good option to keep the door from swinging in?
Also, if I nail off the casing leg and head on the hinge side then I won't be able to install the spreader to keep the jamb legs apart when I lift up the assembly. Should I therefore just turn the assembly on it's side and nail a spreader onto the back side (non-hinge side) of the jambs near the bottom?
Lastly, I am wondering what size and length nails I should use for the casing. The wood is mahogany which is dense and the casing is 7/8" thick. If I go with 1-1/2" nails in the casing at the jamb and 2" in the casing at the stud this therefore embeds the nail 7/8" into the jamb and stud respectively. Is that enough? I guess it also depends on the gauge of the nail. I wanted to use 15ga at the jamb and 16 ga at the stud but these leave bigger holes. Now I understand that nails shot with a nail gun cannot be countersunk and therefore not filled. Is this true? If so I would have to hand nail them in order to countersink and fill the holes. Or, I could go to with nailing 18ga with a nail gun which leaves very small holes, but is this not too small given the species of wood and thicknesses I am using?
Any advice would be appreciated.
Tack on a temporary door stop that is about six inches short at the top and bottom. You can then cross sight your door and place your nails in the areas where the permanent stop will be at the top and bottom. Remember the door stop is your friend and helps you to get the door to close flush top to bottom while installing. Once this is secure pop off the temporary stop and shim and nail off the strike side. Nailing behind the relatively narrow stop does not allow much of a spread for the nails to keep the jamb from twisting, but you should be ok as long as you pay attention as you go. I understand that you want as few nail holes as needed. After handling thousands of doors I never had a problem with holding the entire door assembly together while standing it up into the opening. If you are nervous about the assembly splaying apart you could tack a spreader onto the side of the jamb opposite the hinges until you get the door stood up in the opening. Once it's standing on the floor in the opening it won't have the tendency to want to pull apart.
If your casing is 7/8" and your drywall is 1/2" then a 1-1/2" nail will only penetrate 1/8" into the stud plus a little for the nail being set into the casing. That's not enough to really grab the stud. I would use 2" nails on the casing and 2-1/2" on the jamb if your nail gun has the capacity. Your nail gun, if set at the proper pressure, should set the nail when shot into the wood. Remember to use a little pressure to hold the nail gun against the wood when firing. If you do get a "shiner" you can set the nail with a nail set and hammer. If your opening is not too over sized you can probably get away with 2" nails in the jamb but I like to see those nails really sink into the studs.
Once you install the first door you will understand how all these little tips come into play and the next door will be a piece of cake.
Thanks. This is all really beginning to make sense for me. I think I will likely try using screws instead of nails on the first door to secure the jambs so that if I mistake I can remove them easily.
Would 2" x 18ga then be enough through the casing into the jamb given I am only fastening the jambs along the centreline of the doorstop or do I need 16ga? Also, would 2-1/2" x 18ga be enough through the casing and drywall into the stud?
I also find it odd that shims don't ever seem to be specified at the top and bottom of the hinge and shim jambs. What keeps them from moving there? Is it because the movement will occur at the hinges and the casing will stop any movement at the top and bottom where there are no shims?
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