Exterior door on garage slab

[JackOfDiamonds]

I'm building a room in my attached garage. I plan to build a 2x4 wall and install a door. I plan to buy a pre hung exterior door from Home Depot. But I don't know how to actually install it. I understand I will shim it into the rough opening but I don't know what I put on the bottom. Do I just set it directly on the slab? Put sill seal foam under? A strip of plywood?

The slab is sloped like all garage floors too.

 

[mepstein]

They make exterior door install kits just for this. Flashing, pan, caulk, etc.

 

[Zeke]

I suspect he meant an interior door. Place a shim under each jamb as required to square up the head jamb. Once shimmed and nailed/screwed off on the sides, remove the bottom shims and leave an 1/8th" or so air space., You can also place AL shims there cut to shape. Even 30lb felt would work and so will plastic. Lots of options rather than end grain in contact with the floor.

 

[manwithtools]

I think OP is saying "how does he install and exterior door on an interior 2 x 4 wall?" If its an exterior pre-hung door, it will have an integrated threshold. Just place the door in the rough opening and shim for plumb and level. It can sit directly on the slab , but you may have to shim under the threshold depending on which direction the floor slopes in relation to the door. A little caulking under the threshold would help too.

 

[acer66]

Unless the threshold functions as a separation between floors I would remove it.

To make things easier make sure the framing on the hinge side of the door is or shim it plumb before installing the door.

 

[manwithtools]

If OP wants a separate environment, i.e. heated and cooled or dust free compared to the rest of the garage, then I would not recommend removing the threshold.

 

[acer66]

If OP wants a separate environment, i.e. heated and cooled or dust free compared to the rest of the garage, then I would not recommend removing the threshold.

Good point!

 

[CraigStu]

In our 4 yr old house the door to the garage and the door to the stairs to the basement both have the aluminum thresholds. They also have a wood strip w/ 5 dime sized slot screwheads that you twist to raise/lower the wood. That adjusts to get the seal on the bottom of the door to seal properly. The door to the garage is steel and the one to the basement is whatever wood like stuff they make interior doors of. I have never noticed a problem stepping over the threshold. I had to go look to be sure both had it before I typed this. So yes, I'd get that style prehung door and leave the threshold as is.

 

[JackOfDiamonds]

Yes I am going to air condition the room so although it will be an "interior door" it will actually be an "exterior door".

I will put the threshold right down on the slab but I know I will have to shim it because the floor slopes. As you face the door the floor slopes downward to the right. I can shim up one side with a strip of thin wood and then caulk the crack I guess. But I wonder if it would be better to make a full width shim on my table saw somehow.

 

[Firstram]

Easier to seal a full width shim. Like you said, cut a wedge 0-x/16 on your table saw.

 

[nadogail]

The few doors pre hung doors I have installed came with directions; after reading them the job was pretty simple.

 

[PoorUB]

The man door in my garage needs to be shimmed. I use the composit shims and shim the one side, then one in the middle from either side, they go in maybe 1/4th the length of the shim. Then I caulk the threashold heavily, making sure I get caulk under the threashold. I caulk the whole length. both sides and tool it in nicely. I run my 300 pound snow blower in and out this door and the threshold doesn't even wiggle.

 

[Monza Harry]

Any door (or space) attached to a vehicular containing space will typically have code call outs for "CO/CO2" sealing to any habitable space ie: office, bedroom, den etc. and require a prescribed fire rating. A separated area, like a reloading, woodworking, etc. space shouldn't be, but all bets are off with gov't offices/jurisdictions. Just things to consider as you move forward. Harry

 

[JackOfDiamonds]

Thanks for that. I don't think I'm creating a "habitable space" in this situation.

What I have is a 2-car attached garage with two roll-up doors and a pole in the middle. The man door into the house is on the right side and the left half is slightly deeper with the furnace and water heater on the left half back. I currently use the left half for metalworks including a lathe and welding but that's not good for livability of the right half what with the noise, smells and metal shavings migrating over there. Not to mention I'd like to keep the dangerous tools locked away better and protect them from temperature extremes. I'm building a wall right down the middle, absorbing the post. The wall will have a man door door at the end at 90 degree to the existing door into the house. The new space will be air conditioned so I can also use it for a home office and move my 3D printing and computer in there to get it out of the main house. The bay will technically remain usable as a garage, at least if I moved all my things out.

It's a small space but the wall won't make it any smaller and in fact will give me more hanging space. So it's

Better safety for the kids from chemicals, power tools and guns,
Less noise,
Smoke and chip containment,
Increasing working comfort and usable season for working,
Free up a corner in the main house from my computer and printer,
Allow 3D printing overnight without bothering anyone,
Ability to do work calls from home while other people are home (my work is largely in the evenings),
Maybe slightly more security against things being stolen

 

[Zeke]

If the title wasn't edited I better start paying more attention.

Anyway, If I were installing a door on a slope, I'd modify the jamb to have the threshold level with the sloping floor. I don't want a high edge especially on the lock side. I'd be the first one to trip. This will involve cutting the bottom of the door to fit the frame.

Any exterior door will have an attached sill. Most are AL and the door bottom seals to the threshold. They also should have weatherstripping pre installed.

Man, I thought for sure the OP said something about just the jambs touching the floor. I totally misread the post, They won't with a threshold (or shouldn't ). My post above is not correct as I was assuming no threshold, just a continuous transition from room to room like inside doors.

 

[Leaflessshadetree]

I put sill seal foam under both of mine.

 

[Walkers]

Another easy method for leveling a floor is to just block the opening on both sides of the wall across the opening, so that you have a 3-1/2" x 36ish" opening on the floor and pouring in some quickset cement until it fills the low side and just covers the high side (this is harder to describe that to do. I have taped a couple pieces of steel bars down to the floor, it doesn't take much you just need to make a dam). The stuff cures in 20 minutes. Then just set your prehung exterior door (which should have two rubber strips on the bottom for sealing. plumb the hinge side until you are happy, screw it in, the set the latch side for the best match to the door And shim and screw that in, add casing, foam, and done.