Thank you for reading my question. I replaced our front door awhile back and everything went ok. It's a 36" exterior door with one side light, prehung. After the door was in, leveled and screwed in place I realized that the bottom sill (plate?) and the concrete slab had a big gap. enter image description here Turns out that the new door has a sill with a slope, but the bottom of the whole prehung door box is flat, but the concrete under the door had a slope. So now I'm left with a gap. The door is sealed on the bottom on the inside but as the slope grows, so does my gap. I filled the gap with a 1x6 PT cut at an angled the long way, but the gap wary a little from left to right so it's not perfect. Could I fill this gap with self leveling concrete? Some kind of foam that holds up to the constant stepping on the door sill? Any other ideas?

Thank you for your help!

  • I think if you were to use the self leveling concrete you should take the door off
    – chrger1970
    Jul 4 '20 at 23:31

Unless you want to remove the door to apply leveling compound; builders filler is probably you best bet, This is a two part plastic putty that adheres well and sets very hard, it can be tinted using oxide powder, or painted etc.

It has a strong chemical smell that will dissapear after a few weeks.

  • Thank you Jansen!
    – Bamse
    Jul 7 '20 at 20:36
  • I went to the local hardware store and the guy suggested Rockite and a big bag (like a supersized cake decorating back) mix it quickly and squezze it under the door.
    – Bamse
    Jul 7 '20 at 20:39
  • It worked, but you have to be very fast, it dries in minutes so once you get it under the door you have to squeeze it all out, rinse the bag, make a new small batch and repeat. Maybe mortar would have been better. But it looks good now.
    – Bamse
    Jul 7 '20 at 20:41
  • @Bamse I'm glad this worked for you. Please click the check-mark next to this answer so others will know there's a good solution for it!
    – FreeMan
    Dec 3 '20 at 15:43

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