Please walk me through installing an exterior door in an unfinished basement

Factual Questions
1

A wall in our unfinished basement opens to a flight of steps and a set of extremely drafty Bilco doors. I’ve taken small steps over the years to minimize Winter’s Chill, but its icy hand still creeps through and gives us the icy finger.

All the guides I’m finding start with measuring and taking off the old door—but all I have is bare concrete.

My oversimplified idea is to create a frame of pressure treated planks and insert a pre-hung, basic steel exterior door. None of the prehung doors I’ve seen are set in pressure treated wood, and since it’s nominally exterior-facing on bare concrete, I’m assuming this is the way to go (‘nominally’ because the Bilco doors keep the direct elements out).

My starting questions:

Should the pressure treated planks be 2x6s or 2x8s? Does it matter?

Should I put the planks on both sides, the bottom and the top? Or just the sides only/sides and top/sides and bottom?

Once I’ve framed it, what are the key measurements I need to take before buying the door? Does it make any sense to buy both at the same time by measuring the original dimensions and accounting for the (actual) board width of the planks?

I need to run the dehumidifier hose through the door. I plan on routing a channel for the hose to go through (on the foundation-facing side), putting in a short length of hose with fittings, and caulking the heck out of it. Or is there a ‘right’ way to do that?

To balance things, am I shimming the prehung door frame or the pressure treated frame (i.e. do the shims go between the pressure treated planks and the door, or between the pressure treated and the concrete)?

Am I best off using basic expanding spray-foam sealant/insulation or should I look for a caulk with particular properties?

It looks like the main basement and stairwell were made from separate moulds/forms.There is a tight seam with what looks like that black waterproofing paint inside. Do I need to account for this at all? I think the only place where it comes close to the door is at the bottom.

My shopping list includes:
Pressure-treated wood planks
Appropriate-sized Tapcon screws and/or powder-actuated nailgun fasteners (how deep into the concrete do I want to go?)
Wood shims
Foam insulation or caulk
A steel, prehung door
Basic lockset

Am I missing anything?

This can’t be as straightforward as my plan makes it seem. What steps am I missing, and what are the common (and not-so-common) pitfalls, foibles and screw-ups I’m likely to encounter?

Thanks~

2

Mike Holmes says always put a vapor barrier between wood and plastic.

That’s all I got.

3

I think we need your rough opening dimensions. I’d be inclined to make my frame in such a way so I could use a standard door size. That might mean more wood or less depending. I second the vapor barrier.

I’ve had good luck with a ramset powder hammer. They’re like $30 plus the .22 cartridges and the nails.

The door frame usually has a bottom plate on it so you only need wood for the sides and top.

I’d choose a door and look at the door manufacturers rough installation instructions first.

4

You might look at some Youtube videos:
https://www.youtube.com/results?search_query=exterior+basement+door

5

Yes, try to work the frame out to a standard size. You should be able to buy 1/2" or less pressure plywood to use along with the 2x6s to get it close, then cedar shims for the final adjustment. You can put something on the wood where it meets the concrete if you like, roofing tar, driveway sealer, even paint. I recommend the nail shooting gun also. You may need the longest nails they have to get through 2x boards. I’d suggest predrilling the PT also or the nail might not make it all the way through.

So pick out a door first, then build your frame to that doors specifications.

6

Really? What would you use? A barrier made of concrete?

7

What are the measurements on the existing opening? How far wall to wall and for far floor to ceiling?

Ideally it’s greater than 36x84, then you can work with a stock door. If it’s smaller you may need to order a door specific to your project.

Generally you’d use 2x4’s to frame in the wall/rough opening. I’d do 2x4’s to keep it simple. You could also frame in with 2x6’s as it allows for a more insulated wall but then you’ll also have to extend the jab on the door.

You frame in a wall with a rough opening specific to the door you plan on using. A 30x80 is a standard exterior door as are 32x80 and 36x80. The rough opening for a 30x80 is 32x82 1/2.

The frame has a baseplate(2x4 nailed to the floor except where the door opening will be) nails on that only need do an inch or so into the concrete, it’s not like the boards going anywhere. A header goes above the door opening (This isn’t structural in your case so I’d just do the header with 2x4’s. You’ll have 2 2x4’s on either end of the wall, nailed/screwed into the wall (I’d go a couple inches into the concrete on those if you can.) Then from one side you want 2x4 studs every 16 inches on center.

A prehung exterior door has a threshold included. You could opt to remove that so you don’t have a step or need to worry about nailing it down. If you don’t plan on using the threshold you may want to trim of the door jambs so you don’t have a large gap under the door and adjust the rough opening height accordingly The jambs are going to be made from a composite material or a treated pine, generally they have a lengthy guarantee against rot so you don’t need to worry about it, re-prime the bottom of the jambs if you cut them.

A steel door will most certainly rust over time installed below grade, it will take an eternity to become a structural issue but it will be unsightly on the outside. So you either need to not care or consider fiberglass.

Your shopping list looks good.

Overall it’s an easy project, it will take a carpenter about three hours. I’d expect a home owner to take most the day.

8

I’m not quite clear on the vapour barrier. It’s an unfinished concrete foundation, and I’m considering using pressure treated wood for the frame (no plastic) and a wood-framed steel entry door.

If I do need a barrier between the concrete and the wood, what am I looking at? Basic x-mil plastic (is thickness important)? Or that Tyvek house-wrap?

The opening seems to be 38.75" wide by 86" tall. The top already has pressure treated wood going across it. Complicating things, there’s an armoured cable leading through the bottom and out to the Bilco doors. The armoured cable looks like common BX cable, but it’s much thinner (probably because the alarm wires are relatively small). I assume I’ll be doing a bit more routing to give it space.

The foundation wall is about 7.5" deep—is there enough width to shoot nails in or should I stick with Tapcons (i.e. if I shoot nails anywhere but the centre, will I end up with chunks of foundation cleaving off)?

Since this is an out-of-the-way location and barely visible, cosmetics are wholly irrelevant (we’ve opened the Bilco doors maybe two or three times in the past ten years). So I’m hoping to go with the least expensive exterior door possible (something like this). There are a couple Lowes and Home Depots within reach, so hopefully one of them will have the right size in stock.

That door lists common size (32x80), actual width (33.5) and rough opening width (34.25). Is the rough opening width the one I should be focused on? That is, if my current opening is 38.75", I need to account for 4.5" to get to the rough opening width. Since 2x4/6s are actually 1.5" deep, then I need three total. Does it matter which side has two boards?

The only height listed is a common height of 80". Do I do the same thing and stack three boards under the existing ones and one board on the floor? (Or four boards at the top if I’m taking off the threshold.)

If I do go with the 2x6 (especially as the primary purpose of adding a door is insulation), what does “extend the jab on the door” mean? Or did you mean to extend the jamb? Is that cosmetic or functional? If I keep it simple, will I lose that much insulating impact if I just go with the 2x4s?

I’m not quite following what “Then from one side you want 2x4 studs every 16 inches on center.” means. I get it from a building a wall perspective, but not how it should relate here.

Off to watch door videos. I hope at least one of them features Jim Doorison.

9

Nothing to vapor barrier really, you’re going to have solid wood/steel everywhere. Just caulk the seams. You can staple some plastic around the door on the inside if you really wanted. Vapor barrier would be a thing if you built a bit of a wall, you’re really just putting in a frame.

The rough opening is what matters. Put the two boards on the hinge side. You’ll want that extra depth there. The door will probably come with a few 3 inch screws meant to go though two of the hing holes into the frame.

80 inches is the door slab height. You need to know the rough opening height, which include the sill and jamb. If it will take 3 or more boards to get it down to the rough opening height, Do 2 boards and 3 blocks to space them apart. The remaining space fill with insulation. Anytime you are building a structure you only use enough wood for the structural capacity, other space should be filled with insulation. Insulation is cheaper than wood and wood by itself is a poor insulator.

I meant jamb. In your case it ends up mainly cosmetic. On the outside you’ll have a few inches of exposed PT, trim it out with some primed pine and call it good.

Ignore it. If you had a larger opening you needed to get to the rough opening size it would come into play.

10

:smack: I meant wood and concrete. Put plastic between them.

11

If your jamb is not exposed to the ground, why are you going with pressure treated wood?

12

That’s ok. It’s like that duel between Aaron and Burr.

13

I don’t really follow Mike Holmes (because he is primarily an entertainer) but I highly doubt he says quite this. Best practice is treated (or similarly rot resistant, like cedar) wood against concrete. A vapour barrier between untreated wood and concrete is a distant second, the untreated wood often rots anyways due to moisture trapped against the vapor barrier. Treated wood without a vapour barrier also allows it to be fastened to the concrete properly with adhesive.

14

Even with PT or cedar wood against concrete is problematic. It tends to leave voids where moisture collects that eventually can lead to rot. You do mention using adhesive though, and while I wouldn’t count on that to secure the frame by itself it does work to fill in and protect the wood. But all in all it doesn’t matter all that much, my basement door could easily be 30 years old, it’s just pine nailed to the concrete wall, and though it’s been exposed to a lot of humidity and direct water contact it is only degraded slightly at the bottom of the frame where it meets the floor.

15

I said vapor barrier like the poster before me but what I was really thinking was roll of sill plate gasket for where the wood and concrete meet.

16

[scratches nose] … why not just get better Bilco doors? If the existing ones are drafty but serviceable, just seal them up with a roll of duct tape every Fall.

17

Any wood in contact with concrete must be pressure-treated. Even then it can still develop problems if the concrete gets damp a lot. A moisture barrier may be a good idea.

18

That must be a regional thing, because that is not SOP here in California

19

Every jurisdiction is slightly different, of course, but most have adopted the generally uncontroversial aspects of the International Building Code.

“Naturally durable” includes things like red cedar or other rot-resistant species, but definitely not your typical kiln-dried framing stock.

But it never hurts to ask your local inspector what’s required in your area.

20

This is one of those projects where it would. I doubt the OP has a 4 foot landing in their bulkhead. The inspector would say you can’t do that.