I am 100 percent sure you never have been able to place a foundation on top of a ceiling tile. I have never seen a base where this was done.
I have seen fence stacking and boxing, but to my knowledge…no matter how well supported the structure you can’t place a foundation of any type on a ceiling piece.
I tested before I left for work and I cant do it either.
And I do it all the time.
Square ceilings + square foundations on top do work.
Triangles OTOH…
Odd. I tries with both and could not get them to work at all when stacking. Ill try again. But a no go for me
I have done it on multiple bases as well where needed foundations to support shrines extended from cliff edges but trianges never been able to do that. have to do hollow triangle with column inside to build tower before.
On Squares it will work when you support it with walls or foundations from side (I think one side just needed).
Never try it on triangle and can’t test it at the moment.
This bug has been reported previously. However, it does not appear to have garnered any attention:
In the Steam forum, it was noted that this issue has been corrected. However, that does not appear to be the case:
While I was working at this, I did not thing to try supporting with columns. This sounds like a very strong work around option – THANK YOU!! 
Will the columns allow enough room for a player to squeeze by the column in the “corridor” underneath the triangle foundation blocks?
Normally no think of it as a solid triangle hollow it out and stick column in it not much room to stand in there.
Bah. It is still a functional option that I may have to try.
I have been informed that this bug also still exists presently in TestLive, FYI.
Will this be added to the Trello board to allow the community to weigh in on how this should be prioritized?
Thank you for taking this to your team!!
It is possible that it’s present on Testlive as it’s not been fixed for that build.
We sent the report to our team and they’ll look into it. It will go on the Trello board depending on their progress while tracking this issue down and the impact it has on our community 
Thanks again for the feedback.
I just tried this, and could not make it work. I could not get a triangle foundation to snap-to on top of a pillar.
I tried this a couple of different ways, using walls as skin and also using fence foundations as skin. If this worked once upon a time, it does not appear to work in Live presently. 
So, sadly, there does not appear to be a workaround here that will allow my project to continue.
The last time I checked it wasn’t working on TestLive so I dropped in this morning to test this.
No joy. Also the pillar trick doesn’t work here on TL, but if I remove the pillar at the end, I can place a foundation inside there and it effectively becomes wrapped with khitan on the front side. I know that doesn’t help you, but I thought you’d find it interesting. As I mentioned elsewhere my workaround for now is to top with the “blast shields” or T3 ramps/corner ramps.
oh nooo, wasting all those resources 
sometimes also on testlive when i cant place some buildingblocks i just logg off and on again then its ok
dunno if thats the case here also but…
Its not putting afoundation on pillar its putting putting pillar on triangle them walling around then putting a pillar in middle to keep structure at 100% when you put a ceiling tile on top and you have to do that all the way up making frame triangles with pillars inside and ceiling tiles on top works just like a foundation.
Well, for my purposes, it does not work just like a foundation since you cannot attach an anti-climb fence to the face of a wall. You can only do that on an actual foundation block.
Ah you are wanting to put it on face of wall instead of top and yes that isn’t possible without foundations.
You can try to make the backside of your wall a half block higher than your front wall and made two ceilings instead.
To explain: Build on the back side of your triangle foundations (the ones that attached to ground) a sandstone fence. You later destroy them so no need for T3. Then you place inside the fence a fence foundation. It need to looks like the top of the foundation is inside the fence. I’m sure you need to try it at different points cause it sometimes don’t work. Then you can destroy the fence. At this point you can made the front side as high as you want your climbprotection. Then build first the the backside of yor wall. You can now build a ceiling at the front side and a half wall higher a ceiling at the backside. Now build the protectiv fences at front. Keep in mind that at this point the upper wall just supported by the back side. I’m not sure that it really work, cause I use the half higher foundations in another way and can’t try it out now but maybe it is a workaround for you.
It’s not in the latest patch notes, but it looks like this works on the latest testlive now (as of 20-02-19).
Sweet Baby Jesus… bless you, Funcom! Hats off for ack’ing this bug, and working so quickly to include it in your list of fixes.
