DeanXeL's Basegame Builds and building tips/building around glitches :)

The issue arose around the time platforms were introduced. It is possible that by introducing a difference between "ceiling" of the lower floor and "floor" of the upper floor (needed for platform levels), an issue was introduced with the usual way people make lofts. This way deletes the floor of the landing, but (unless the loft is exploded) not the roof of the floor below. This discrepancy makes the sims think there is still a ceiling and they can't use the stairs, because they 'bump their head into the invisible ceiling'. It appears that staircases only remove the "ceiling" of the floor below if they have a "floor" on the landing to remove as well. This is how this workaround is made.

In general exploded lofts are counted as outside, so they will influence the 'darkness' of your room, allowing light from outside to enter through the missing ceiling. They will also behave strangely with seasons and any kind of trims.

Remove one piece of railing from your loft, if it shows the ceiling from the floor below (red), your loft was NOT exploded, just use undo to go back to your non-exploded loft.
https://i.imgur.com/Z4pVTnk.png

Another way is to select the room below the loft, go up to the loft floor and click the yellow ceiling edge. If it says "Build ceiling", your loft is exploded. If it says "Remove ceiling", your loft is ok.
https://i.imgur.com/eEKQXhR.png

This is like you would have done before, but with 1 single extra step
a) Create a spot surrounded with fence where you want your loft (yes, this can also be full walls/half walls or whatever you like. Place the stairs over the fence, where you want it to be and delete the floor in the loft area (so far, just like you would have done). This loft already looks like a normal fenced loft, but if you select it, it selects the entire open area, including where the staircase is and it is NOT functional

!! I didn't place the stairs first, just so you could see the area, but you might want to place it before removing the floor.
https://i.imgur.com/vorkp5i.png

b) Add a platform over the stairs, you can see when you lower it where you put too much, the tiles will remain visible where they were too much. !! THIS is the step you need with a non-functional staircase in a non-'exploded' loft!!
https://i.imgur.com/YcyLAkQ.png

c)Drag the side of the platform back towards the stairs to cover any visible tiles with the removed floor (basically only necessary if you added too much platform).
https://i.imgur.com/lrGwj7Q.png

d) Add the fence next to the stairs to finish your nicely fenced loft! Don't worry if you accidentally dragged the fence over the entrance to the stairs again, they will still be functional. Are they not functional? Just remove the stairs and replace them, sometimes it just needs to recalculate (maybe you added the stairs after removing the floor? ;-) )

https://i.imgur.com/yTJa1Ba.png

a) Create a spot surrounded with fence where you want your loft (yes, this can also be full walls/half walls or whatever you like. Place the stairs over the fence, where you want it to be and delete the floor in the loft area (so far, just like you would have done) !! I didn't place the stairs first, just so you could see the area, but you might want to place it before removing the floor. This loft already looks like a normal fenced loft, but if you select it, it selects the entire open area, including where the staircase is and it is NOT functional
https://i.imgur.com/G9c5E0q.png

b) Add a platform to the sides of your loft, all around.
A single row of platform will not do, it will just lift the fence
https://i.imgur.com/6dzLAu1.png
You will have to drag the platform through the fence to make the fence disappear.
Red: the area where the platform touches the outside wall: the outside wall disappears! Just click it and choose: build full wall, no problem. Also, you can already see the stairs cutting through the platform, we will come back to this later.
Blue: My mid-room loft was too small to put platforms all around in one go without losing the open space altogether. Either start with a bigger opening or -as I did here- Drag the platform outside once placed to create room again to place the platforms on the other side.
https://i.imgur.com/DIxQsyF.png

c) Finish your platforms all around your staircase (left) and lower them (I already did this on the right one)
Blue: you can see on the left staircase the platform was placed on the left over the staircase, but by dragging the right platform out, there is still a bit of open space in the middle now!
https://i.imgur.com/mIVvusE.png

d) Lower all the platforms. For the left staircase, you see there's one tile too many covered to make a nice open loft: Drag the 'open space' out one tile to cover this. (Blue circle) Make sure the open space does NOT cover the staircase! It should be next to it/around it.

This will be a bit more annoying with the right, this is a corner staircase. We already covered the upper part of the stairs with platform, but how much do we actually need to cover? Drag The arrow of the previous platform (blue circle) down to cover more of the stairs

https://i.imgur.com/tSSnYIz.png

e) The left loft is done!
The right one was covered too much, you can see the floor tiles over too much of the area. Drag the platform back up one tile.

https://i.imgur.com/BqljSgi.png

f) Sometimes you get in a spot where you can't use the arrows to drag anymore to make the shape you need. We just need to get rid of that one block next to the staircase, but the arrows only allow to drag both the block we need to remove and the block that has to remain over the staircase
https://i.imgur.com/HPLrtxC.png

Solution: build a piece of platform on the bit you want to remove, this will give you more options!

https://i.imgur.com/YF9PZbK.png

You now have two arrows, one over the staircase and one over the raised piece of platform. Drag the arrow up over the raised piece of platform to finish your loft.

https://i.imgur.com/Ap9fIax.png

g) Both lofts are now finished! You can keep dragging the empty loft out (be careful NOT to cover your staircase again) or add pieces of platform to get the exact shape you like. You can also add fences if you like. However, if you want to remove a fence, either replace with another using the replace tool or go back to point b) to remove it completely.

https://i.imgur.com/qx5bTMD.png

Basically this means you have to remove the exploded loft altogether and build a new, functional one. This is how you do it:

a) Select the room below the exploded loft and click "build ceiling". This fixes the ceiling from the room below, but not the loft itself yet, it is still exploded.

https://i.imgur.com/9V4m8jY.png

b) Click the area with the exploded loft and drag the walls in until they touch, so the exploded loft is completely gone.

https://i.imgur.com/aBKGAIV.png

Pick either part 1) for a building a fenced loft or 2) for building a loft without separation.

This is what we're going for:

https://i.imgur.com/Udh8VdQ.png

1) if we drag the platform over the staircase AND the platform, the ceiling stays above the platform...
https://i.imgur.com/Xew60tQ.png

2) If we just draw the platform over the staircase, somehow, sims still 'bump their head' in the ceiling above the platform, much like they would if you don't put the floor back over the staircase.

https://i.imgur.com/H0O8Ddm.png

3) I'm sorry, but there really isn't a good fix, since platforms do NOT remove their own ceiling, the only thing to do is lower the landing to a height where the sims could stand on it if it had a ceiling. Then the normal loft workaround does the trick (see 1) or 2) and just take into account the staircase leavind the landing, the other one is not important.

https://i.imgur.com/CmfMDk3.png