I just removed my rotten floor in my home I just purchased. It's an 80yr old home which I plan to resale. I added plumbing fixtures in one room which is now the bathroom and as well in another room for a future kitchen. Here is the dilema, I have about 8" to get to where i want to be in height. I want to pour cement. I had 2 people tell me 2 different things. I was told by both that I need 3/4" rock. One guy said I should put polyurethane (for insulation)then mesh then pour cement(25kpa). The other told me I don't need to spend the money on polyurethane and I don't need mesh. I'm better off adding fiber to my cement instead of the mesh and since it is minimum 4" thick I'm OK. He also said that 20kpa is all I need because it is not a garage and that 15kpa is the minimum anyway.What do you think I should do.

Sounds like you want to do a good job, but don't want to spend a lot on a house you will sell.

I think if you are in a wet area, use plastic. it will keep the slab dry later. If the area is dry you really don't need the plastic.

I would use mesh, it will hold the slab together if it cracks, but the minimum mix is OK, doesn't sound like there is a lot of stress on the slab.

Good luck roger