Our house has a side door that leads into the basement. It is an older wooden door, and has a wooden storm door mounted on the outside. I'm pretty sure both are almost as old (if not the same age) as the house- the storm door is getting rotten on the bottom and I found neither one has any weatherstrip or seal or anything on the bottom of them so cold air and bugs get in underneath.

My plan is to replace the whole shebang with a single, solid exterior door (probably fiberglass). I have been looking at prehung doors (it is a 32" door). The existing door is mounted in a wall that is brick on the outside, and (I presume) plaster-lath on the interior,

One big question that arose is with installation. On the existing setup, the face of the storm door is recessed into the brick wall about 3", making it about 8 1/2" from the face of the brick to the face of the existing door. Given that prehung doors have trim on them that looks like it's supposed to be installed against the outer surface of the wall you're mounting the door in, would I have to remove that trim to install the door? Also, the existing sill area under the door is concrete, what's the best way to mount the new sill cover on the new frame?

 

A new prehung will usually come with brickmold trim on the outside. That trim will lay on your wall sheathing, which is the surface immediately behind the brick. So it will appear to be recessed into the brick about 3" like you say. So your existing trim will be removed. So will the old door jamb, and hopefully the concrete below the door is level. If it isn't you will want to use a cup grinder to make it level before you put the new door in.

Your new door comes with a sill that will sit on the concrete. Once you are ready to install it, you run a couple heavy beads of sealant on the concrete and set the door into it. You do this where the solid part of the door sill will be, not where the hollow aluminum sill nose is.

The brickmold measurement will be 36x83 or so, if you want to see if it will fit... or if you will need additional trim around it, or maybe you will remove the brivkmould and use something 5/4" thick but wider, in order to fill the space.

You will want to measure the wall thickness and get a door that is the right width for your wall. This measurement is usually the distance from the drywall surface inside to the interior side of your storm door. (To the exterior side of the sheathing, if you have removed the storm door and trim.)

 

So here's my question- I went to Lowe's and measured the face trim on the door I'm looking at. I measured that at 36 1/8" x 83 3/4", whereas the existing framing. which is recessed into the brick, measures 35 1/2" x 82 1/2". So the face trim on the new door frame would have to come off, would it not? I'm guessing I will have to buy new trim for that.

I might have to get a picture. The other measurements all seem to be fine for a standard 32" door.

 

Yes, it's pretty typical to have to take the brickmould off. The door should usually get installed flush with the interior wall. If your wall thickness is strange, which it usually is in older houses, you add an extension jamb onto the outside of the jamb until it's flush with the sheathing, then you can cut the brick mould down to the right width on a table saw, cutting the outer perimeter, not the inside perimeter, and put it back on.

Your height sounds a bit short, so you may have trouble with your height. You need to also measure inside, since your finish floor height to the top of the brick is what you need to worry about or the door won't fit. Yours sounds too tight. Rough openings can always be made bigger, but brick openings can't, at least not easily.

 

Hm, I'll have to check that height. The floor height shouldn't be an issue as the existing sill under the door is just bare concrete from the looks of it.

The outer storm door measures out at 32 x 80 3/8" which looks to be more or less the standard size...however I have no idea what size the existing jamb frame is, but it should be similar to the prehung door right (which I measured on the outside at 33 1/4" x 81 1/2")? I didn't measure the entry door, I just figured it was probably the same dimensions.

 

Prehung doors are usually exactly 33 1/2 x 82. But if your new one measured 83 3/4 outside it might be 82 1/2 tall.

 

Looks like I ran into another snag. I pulled the interior trim off to check dimensions of the existing jamb. It looks to me like this jamb is built into the existing framing inside the house (this is a 70 year old house, it has plaster-lath interior walls). The broken out sections of the plaster were already there when I pulled the trim off. I measured the outside of the jamb and it measures about 33 1/2" wide x 81 3/4" to the top from the floor. Can I even install a prehung door here or will I have to get a slab door?

 

You will want to take a Sawzall (with a 9" demo blade for wood/ nails) and just cut that old frame up into smaller pieces. On the sides, you can either pry the jamb off the nails or run the Sawzall down the side to cut all the nails. In your first and last picture, the part that goes up into the plaster on the top corners can just be cut off and once you cut the top jamb out, those pieces will most likely just fall out.

Once the old door jamb is out, you will be able to measure how tall your rough opening is. Then you will likely need to cut off the plaster higher so that the plaster is flush with top of the rough opening.

The next thing you will run into once the old jamb is gone is your wall thickness will not be right. In many cases you would just want to buy a prehung door that is made for a 6 9/16" thick wall (4 9/16 is the most common size sold in stores, but they also usually stock 6 9/16 or at least can order it.) Your wall thickness will likely be some oddball thickness like 5 1/2 or something. Especially with a door in a brick opening, it's easy to get the thicker door and just build the outside of the opening out, padding it out with whatever thickness wood you need to equal 6 9/16.

 

OK, so I can still just cut out the old door frame? I wasn't sure if I'd run into issues doing that or not.

With the old frame out it looks like the rough opening should be close, I might need a couple extra pieces on the side to screw it into and shims. The frame piece on the side going up into the slanting ceiling (this is on a landing on a stairwell) looks like it just ends where it meets the ceiling but I can't tell for sure.

Thanks for all the help by the way!

 

Yep, nothing wrong with padding the rough opening to make it smaller if you need to, but you might find that you need to shift the door all the way to one side to help it miss that angled ceiling.

Both sides of your jamb are likely exactly the same so it goes up behind the angled ceiling just like it does o the opposite side.

 

Well I got the door installed today, took me about 6 hours, total pain in the ass.

I started taking off the trim and found out that behind the trim on the outside of the door, there were 1x6" (I assume) boards on the sides and top that went behind the brick, with the frame actually nailed into it from the inside. I pried it out a bit and went around and cut the nails, the top board fell out but the side boards wouldn't budge. I had to knock the frame in toward the inside with a hammer and then cut it at the sides (near the top) because it was wedged in behind the plaster (as a side note, the walls looked like they had some kind of fiber board on them with plaster applied over top? Looked weird to me).

So, after the frame was out I made a cut down the side boards with a sawzall because they were too narrow for the frame to go in (I could have put it in from the inside but there wasn't really room inside to do that).

After that I ended up with a rough opening that was way too big...fortunately the concrete was level and when I set the door in it was level, but I found out the opening in the wall was crooked, and I ended up with 3/4" shims in a couple places. Had to use a lot of expanding foam to fill in that gap, but I was able to secure the frame in place with 4" deck screws. Also had to put a piece of 2x4 across the top of the new frame as there was nothing there once I pulled the old frame out.

Still not sure what I'm going to do on the outside, I have gap there too obviously (it was a 6" deep mounting as you predicted). Bought a Masonite door frame extender kit but it's junk, $48 for 3 boards and a sill plate extender piece that I don't need, no instructions and no hardware. Going to see if I can find the right size lumber to just make my own and install new trim.