can you lay terracotta tiles on top of floorboards?

The best practice is to put a stable layer between the floorboards and the tile. The reason for this is to keep the tile from bending (and then breaking) underfoot. The floorboards have a natural give to them that the tile does not. Best to lay a stable layer, be it plywood or a purpose made structural item available at home stores before you lay the tile. Best of luck! It's actually fun to do, and the results will astound you.

I would first be worried about the floor joists under the floor boards. An older house often doesn't have much for support. If there isn't enough, they will have to be reinforced before anything else.

Yes, you can tile to floorboards. They are generally thick and stable as long as they are well supported underneath.

Conventional industry wisdom wants to lay down cement board on any surface you tile, as it will add strength to the floor.

The newer trick is to use a tile membrane instead of a cement tile backer or even in addition to tile backer. A plastic layer that allows the floor underneath to move without affecting the tile. And, depending on the product, there are other benefits like optional complete waterproofing of the surface to be tiled which is good for showers.

You need to subfloor with a masonry board (concrete) made especially for tile base. It is nailed down. Be sure to nail every few inches and walk over all of it looking for squeaks. If it squeaks, the tile or grout will crack. Then put the tile according to directions using the adhesive made for the type of tile you select. It isn't hard to do but it is heavy work since the materials are all heavy and awkward to handle. The finished result is worth it.

As a tile distributor, as long as the floor boards are screwed down at least every 200mm, you can use either a Solid tiling board(Marmox), or a floating floor membrane (Such as the Schluter Ditra matting).

As long as a flexible adhesive and grout is used, you should never have a problem :)

You'd have to create a very stable base for them. Probably good quality board (not sure if its ply or chip you would need) - we put this down on floorboards to tile our bathrooms.

you can do but only after a bit of work ..first ..use plywood ..4-6mm max ...15mm screws ..every 200mm max ..all over ..then pva the sheet ..to fix tiles you will need both flexible adhesive and grout....best to put tiles down before pva is dry ...however this will raise the floor level higher than other floors ...and you may have to cut the doors at base

make sure that the surface is sturdy & flat,,any gaps under any stone or stone like materials can cause it to snap.tip: tap the top and listen for a hollow sound, if there is that tile must come back and be reset.

You will need to lay 18mm ply on top and screw down. Then when you lay tiles on top use a flexable adhesive. PS the ply comes in 8x4 sheets. Good luck.

yes, what you need is really thin plywood inbetween, and then special adhesive to fix them down with, its not rocket science, ask at your hardware place or builders merchant.

just lay the tiles down and glue them together over where there is nothing under them and get on a ladder and jump on them to see if they will hold