I am replacing the front door I have with a new unit – the old one was looking tired and out of style. I am looking at buying a new prehung door from HD.
My concern is that the old jam is not a standard size and that the opening will be too small or too big. I won’t really know until I rip out the old jam.
What do I do if it’s too big or small?
I am thinking if it’s too big add shims and fill any gap with insulation or caulking and cover with trim. If it’s too small, make several cuts with a circular saw and chisel out to make a larger opening.
Is this the way to go?
The size of the exhisting door ( not the jam) 33 3/4 x 80 1/2.
Thanks
Replies
Remove the interior trim and measure the rough opening.
AH, The beauty of simplicity!
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Took your advice. Now I am more confused than ever.
I can't tell where the jam starts therre are so many layers. Did I mention that this is an old house? Complicating matters is that there is a window opening just above the door and everything seems to be tied in together.
I am going to borrow a digi cam and post photos later this week.
Just as Uncle Dunc said remove the interior trim and measure the R.O.
>> I am going to borrow a digi cam and post photos later this week.
Good idea. Remember to get as close as you can and still focus the camera. If you can arrange it, some side lighting makes it easier to see the edges of things.
Complicating matters is that there is a window opening just above the door and everything seems to be tied in together.
Sounds like you have a transom over door configuration and they may have been built and installed as one unit. If you don't mind my asking, why are you replacing the jamb? If your existing jamb is in decent condition, (not beyond repair/ restoration), I would think that hanging a nice vintage style door in your existing opening would be simpler and you'd be doing that old house a nice bit of justice. If you are thinking that this is a more difficult task, think of using the old door as a template and you'd also be able to make any corrections in the fit by examining any shortcomings by the last installation. A standard sized door will fit your opening width (2'-10") and you may be able to eliminate that extra 1/2" door height by installing a weatherstrip saddle. Don't forget to measure the door thickness! By the way, H.D. has it's practical uses but ordering a vintage wooden door isn't one of them. Visit your local lumber/ millwork supplier.
Good luck, Joe
Standard construction would have (looking at a vertical portion of the jamb) the jamb itself, roughly an inch thick, then a gap of about 1/2 inch, then two 2x4 studs. Over the window you'd see the jamb, then maybe an inch gap, then the "header" built up from two 2x10s or some such.
In the case of a transom above the door, usually the door and transom are "mulled" together before they are installed. So the header would be over the transom.
In an old house things will be confused by the plaster as much as anything else. Likely the plaster will come right up to the jamb, so you won't be able to see the studs alongside it. You might be able to cut away some of the plaster with a utility knife in order to see what's next to the jamb.
Note that you should check near the top and bottom on both sides to get a good feel for the rough opening width, as the opening may not be square.
Be careful of the thermatru doors. They are not the same size as most others (as my boss and I have found out over a few front door rehabs).
Rob Kress
Rather than HD, try a real, local millwork supplier. Chances are, you'll get better advice and a better selection and maybe faster and free delivery.
Don't forget, doors are 3-D. Measure your jamb thickness.
Al Mollitor, Sharon MA
Generally, a rough opening is 2 1/2" larger than the door. A 2'8"x6'8" door would be framed 34 1/2" x 82 1/2". This is a rule of thumb and there are exceptions but a standard door will fit. Always check with the manufacturer. If the opening is a quarter or so less you will be OK as long as the frame is close to plumb. Your interior floor may be higher than where the door actually sits (on the sub-floor). We lift doors up 3/4" off the sub-floor to allow for the finished floor and a carpet. Most doors come with a board attached to the bottom of the sill for this purpose.
Doors are also sized to wall thickness. 4 9/16" or 6 9/16". One for 2x4 construction and one for 2x6.
Altering an opening depends on the load over the door and how the framing was done. If the opening is too large, lucky you. Simply add what you need. The trim may cover adding a 3/4" board to each side. Same at the top.
If the opening is too small. You can gain width by removing the jack studs and replacing them with thinner stock. eg: take off the 2x jacks and replace with 1x. You can add a strong tie bracket under the header too. The header can also be cut a little to gain height if it is already substantial. In both cases you have to be carefull not to weaken a load carrying assembly. With a 2'8" door you should be fine.
Another issue you may face is the exterior. There can be multiple layers of siding. The standard exterior trim may not match or fit. Doors can be ordered without the exterior trim so you can make and apply what you need. Don't forget that typical screen doors will not fit over 3/4" stock, you need 1 1/16" thick. The distance between the outside trim should be the same size as the door, 2'8".
I agree with JoeG. If you have a nice old house you should not, I repeat NOT, mangle it by putting modern plasic or stamped metal junk into or onto it. The things you will achieve: you'll succeed in wasting a hunk of plastic or aluminum - these things have a predictable and *short* life span - and will also succeed in reducing the value of your house. If I guess right, the door, transom, and sidelights (if any) were all built together in a millwork shop, and trying to put a prehung door into part of that opening would result in trim conundrums that even a construction genius would have a hard time solving.
OW
p.s. Do you have door PB to go with the jam?