Hi
I have an old wood threshold that is directly attached to the cement exterior cellar walk out door that exits to back yard in 1971 small ranch. I don't see any screws, so I assume it's glued down. I purchased a new solid oak one at Hd for$89. It's close to the dimensions of the old one, but I'm going to have to make some adjustments.

The present threshold rubs slightly against the interior door (inswing), and also on the screen door. What should the gap between the bottom of the door and the threshold be?

2. What about the screen door gap between it and the threshold? Do I seal the gap somehow afterwards?

3. I'll be using a rubber sealer attached to the inside back of the door (already on door) to seal against bugs, etc.

4. What do I use to attach threshold to cement? A glue or loctite?

5. Do I seal or varnish the unfinished oak threshold?

Thanks!