Looking for some help on how to tackle a project.

The entry way (this home is about 50 years old) was originally sunk 1.5". I think that it was raised with self leveler after the fact to match the rest of the flooring and then tiled over. The area is about 140 sq ft total. The flooring became brittle and soft in places as the subfloor broke down over time (I guess). I would like to level it out and then tile over it.

Any suggestions on the best (cost effective + reliable) solution to raise it back up to tile over? Pour concrete with rebar/hog panels? Tongue and groove OSB and tap con screws into the foundation? Do I need a moisture barrier? Self leveling seems like the obvious and most expensive option. I would like to DIY.

I have about a six inch drop that I would like to bring up and be level as well.

Not sure the best path forward.

Fiberglass infused concrete wont require steel. Can also get bonding agents. Talk to your concrete suppliers about what is available for this job. Husband of Mrs RayBob's bestie in Can. is a salesman for concrete products and they have corporate offices in DFW. Sorry don't know the name but he was telling me when we were recently up there of all the products they have and make and differing applications. Lot more tech than I ever realized.

Your going to need to remove that old sand mix first. If that’s poured over a concrete slab I’d just pour it back with maximizer concrete.

It has been demo'd. I was leaning towards tying it into the existing slab with rebar as well as some hog paneling for reinforcement.

Had a similar issue on mine... I glued pavers on the sunken part it raised it up to correct height.

I wouldn’t bother with rebar. Put some bonder down and good concrete. You can add the mesh if you want but it won’t do anything.

I have the exact same problem with a add on to this 1960 farm house. Had talked to a few people about it and the bestest idea that wasn't going to break the bank was to glue & screw 3/4" PT ply to the concrete. Glue & screw 1/2" backer board onto that and then tile over the top of that which would bring the total height up to that 1.5" deficit. I was going to be using a threshold to meet the difference between the newly tiles floor and the wood plank flooring it will be meeting. My second best guess was the fiber-crete which would be way more expensive and having to mix up 250 sq ft of crete in this confined space would suck. It's a very large master bath.

7 sack pea gravel mix or a polymer modified self leveling cement used for overlays.

I like this idea the best, to be honest. Least messy and most convenient for me, personally. Would you use a vapor or moisture barrier?

Cement mixes: I've read up on Sakrete Maximizer and Quikrete original--they seems to be popular choices for what I would be doing, but the spec sheets say 2"+ minimum thickness on both. I'm only looking for 1.5" total. Seems like I may be asking for trouble.