Entry door threshold moving

[Byron]

I've an annoying problem with my front entry door. I've noticed that the threshold is shifting outward (especially on the RHS) and that a gap (1/4 inch) is now visible between the threshold and the hardwood floor. The culprit seems to be the concrete slab outdoor where the outdoor stairs start. There is a clear movement of the slab (gap between the house wall and the slab). For some reason, part of the threshold is connected to that slab and it is therefore moving along with the slab. I've noticed that this movement is still "active" and my fear is that I should act asap before more damage takes place. What should I do? I was thinking of removing the door to access the threshold and "see the extend of the damage"; then maybe have a new slab or equivalent put in and a new door..... Maybe there is an easier (I mean cheaper) fix? Any help would be greatly appreciated.

[HayZee518]

I'm thinking that the slab and the house foundation are moving at different rates. If the slab were part of the house foundation, not independent of it, it would travel with the house. dependent on which state you live in and how the winters are will determine the "fix." Another thing to consider is what sort of "ground" the slab is on - sandy soil, clay etc. drainage rain run off etc. ok, I just reread your post - the slab is moving independent of the house. the threshold should be part of the door casing or bottom plate and not overhang the slab or be fastened to the slab.

[Byron]

Yes. That's the thing. I guess that 18 years ago, when the house was built, the treshold was partially attached to the outdoor slab... That's quite ridiculous but I guess world is not perfect... I believe I need to somehow "disconnect" the threshold from the outdoor slab and see how I can replace it at the correct place. The main thing is to stop the shift. Any idea out there?

[pushkins]

The door's threshold should in no way be "attached" to the slab, at best it should only have a bead or two of silicon under it. The threshold is attached to the door jams, if the threshold is moving outward then it needs to be re attached to to jams. More importantly if it has become unattached then the usual reason is either rot or dry rot. I'd be looking for one of these reasons and possibly either removing and repairing the existing door or replacing it if needed.