/diy/ - Do It Yourself

>>2845303
Threshold not mechanically fastened to floor or anything else and the tiny beads of caulk that were "holding" it have failed

>send some screws through the jam into the studs on the hinge side.
kek
>>2845299
Screw holes in aluminum thresholds are nearly always placed so they are on the interior side of the door or undeneath it where seals and the door bottom drip edge protect them from direct contact with water.
Also when you install them if there's any possibility of water getting at those fasteners you squirt a big blob of sealant into the holes to fill the space between the floor and the extrusion, and apply extra to the bottom of the screw head before driving the screw home through the blob of uncured sealant...done right this creates a solid rubber gasket that prevents any water intrusion and also helps glue the threshold in place.

A proper installation of a 36" exterior prehung with an extruded aluminum threshold like that should use most of a tube of caulk just to seal the lowest 12" of the unit underneath the threshold and up the sides of the jamb legs to fill any gaps that might allow water intrusion if the area gets inundated and/or subjected to driving rain and wind.
And that's before any flashing or trim goes up.