I have a door in an exterior and one in an interior. Here is the exterior door in question. http://i767.photobucket.com/albums/xx316/randomguyface/2012-02-08_00005.jpg In the CK, I have made absolutely certain not to place the teleport marker below the level of the boardwalk, even tried putting it considerably above it, and as far as I can see, it does not collide with anything. Yet every time, no matter what I do, walking through the door from the inside puts me halfway inside the boardwalk under the water. How can I solve this? It can't be the water can it? They have buildings above water in Riften and Morthal as well.

bump, still having this issue

Bump again...

Please someone help? I've heard I'm not the onky one who's experienced this problem.

Could you post a screenshot what it looks like in the editor?

I guess you could try a different boardwalk.

http://i767.photobucket.com/albums/xx316/randomguyface/csskorheimdoorproblem.png is what I see in the CS. http://i767.photobucket.com/albums/xx316/randomguyface/2012-02-12_00002.jpg is what i see just after I use the door to exit the house. The door marker was originally flat against the platform at the edge of the door, but I tried and that doesn't work either, so I did it higher to see if it would be any better but I get the same result.

Try moving the marker further away from the door.

It looks like a seam for the pieces of boardwalk is right by the door, so perhaps (just a guess) you're not actually loading below the boardwalk but in a tiny gap between boardwalk pieces.

Even if that's not what is happening, moving it a little further away may help.

Did you add navmesh to your boardwalk?

I'm new to this and I thought that navmesh affects only NPCs but does it also affect player?

I had a similar issue. I've added a dirt cliff to extend the landscape and then I put the house on the top of it. Everytime I would teleport out of the house I found myself half way inside the cliff. Then I fixed the navmesh and I put it on the top of the cliff (removed the original that was underneath the cliff) and all of the sudden I was teleporting correctly with both feet on the ground.

Now, in your case you have water underneath so should you have both navmesh in the water underneath the boardwalk and on the boardwalk? I'm not sure... But I'm sure you have to have navmesh on the boardwalk.

I also thought navmesh was only supposed to affect NPCs, but as we see here, sometimes things aren't exactly as advertised in all situations.

Finalizing a navmesh 'links' the door marker to a navmesh triangle. so yes, you need a finalized navmesh, and make sure the navmesh is above the boardwalk. It tells the game where to put you when you 'appear' in the new location.

You will get a 'green' navmesh triangle that will attach to your doormarker.

I am familiar with the step you are describing, but I thought in practical terms it only affected the NPCs. Are you saying that a navmesh also affacts the player? If so, only with load doors or in other circumstances as well?

I have not tested it, but if your having problems with the player not materializing where the door marker is set, there is only one other explanation. You are using a dirty save game with 'pieces' of your mod in different states saved in it.
So, always use a save game that has never had your mod activated when you test your mods.