Exterior door threshold advice

[Mpayson]

Looking for some advice on installing a threshold here - was thinking pressure treated 2x4 for the sill and then threshold on top. Any recommendations?

 

[slownsteady]

Wow, this has been sitting unanswered for a month??? C'mon guys! I know someone has the proper way to do this!

 

[slownsteady]

So am I looking at the concrete threshold beneath the green door? What is the purpose of adding something in front of that? I think you may just want a door sweep to fill the void under the door. It looks like there is another door just to the right of the green door, so anything you put there could interfere with the second door (the one on the right).

 

[joecaption]

There is no great way to do this one.
I'd bet just a sweep will not work, reason being from what I've seen in the past in old buildings like that is that slabs never level or flat, and the door most likely is not plumb.
As the door opens the sweep gets tighter and tighter.
If I had to do it I'd be using a threshold like this one.
https://www.homedepot.com/p/Frost-K...-Adjustable-Height-Threshold-DAT39H/100121731
When you get it, it's going to be to long, which is a good thing, you cut it to length (using a compound mitre saw going slow until you get through the rubber seal, any blade will work) open the door and use that sample cut off piece to set against the end of the door so you'll know how much will need to be cut off the door so it will make a tight seal, and also to mark that door stop molding where it will need to be cut to fit in the threshold.
It's best to remove the door when cutting, then it should be primed and painted after cutting or it's likely to rot.
Threshold should be set in a bed of silicone, to support the over hinging part outside I always use 1 X 4 vinyl lumber attached with TapCon screws pushed up tight in the slot under the threshold laying flat on the concrete.

 

[Mpayson]

So I ended up trimming the jambs up to the top of the floor. I ripped some 2x6 for the toe kick, screwed it to the door frame and put construction adhesive between it and the concrete. Put another piece of 2x6 on top and then an oak threshold trimmed to size on top. Trimmed the door in the pic and the screen door to the side and installed a sweep. Pretty happy with how it turned out.

 

[Mpayson]

There is no great way to do this one.
I'd bet just a sweep will not work, reason being from what I've seen in the past in old buildings like that is that slabs never level or flat, and the door most likely is not plumb.
As the door opens the sweep gets tighter and tighter.
If I had to do it I'd be using a threshold like this one.
https://www.homedepot.com/p/Frost-K...-Adjustable-Height-Threshold-DAT39H/100121731
When you get it, it's going to be to long, which is a good thing, you cut it to length (using a compound mitre saw going slow until you get through the rubber seal, any blade will work) open the door and use that sample cut off piece to set against the end of the door so you'll know how much will need to be cut off the door so it will make a tight seal, and also to mark that door stop molding where it will need to be cut to fit in the threshold.
It's best to remove the door when cutting, then it should be primed and painted after cutting or it's likely to rot.
Threshold should be set in a bed of silicone, to support the over hinging part outside I always use 1 X 4 vinyl lumber attached with TapCon screws pushed up tight in the slot under the threshold laying flat on the concrete.

I considered tapcon screws, by the concrete was only about 3 weeks old, so i was a little nervous about cracking it. The construction adhesive seems to be holding pretty well

 

[Gary]

I'm thinking the construction adhesive may fail eventually with the constant stress of foot traffic, especially with the leverage of the overhang. A couple mechanical fasteners could still be added to back up the adhesive. The 2 together would be a good marriage.

 

[joecaption]

There should also be another piece added between the bottom of the threshold and the slab to lessen the amount of overhang.
If that's a Red Oak threshold it's not going to work, it's going to rot, turn black from mold.
The end grains on red Oak soak up water like a straw.

 

[mabloodhound]

The threshold should also have a stop in it on the outside to seal against the door to prevent air & water infiltration. If you look at full exterior thresholds you'll see them already rabbited in. I'm guessing that's an interior threshold.