Insulate under threshold sliding door section.

[Wadersss]

Hello.
This weekend I'm going to install a new door.
How do I best insulate under the threshold?
It's going to be on a concrete floor.
The slab also has a slope, so there will be a larger gap. 1 cm to about 5 cm. 2 m wide.

 

[Biggle]

Perhaps use expansion tape on the outside and insulation internally... or foam sealant. It's important that it can breathe outward but be airtight inward.

 

[Wadersss]

Thank you very much 👍👍👍

 

[Matti_75]

Well, consider that it should be sealed tightly under the threshold so that any water doesn't flow in. Soft sealant on the outside, then.