You would be surprised at how nice old hardwood floors look after a little scraping, washing and a good coat of wax.

Three or four coats of Kilz2 special.

It is a bit thicker, is made of denim, and serves as a cushion, sound and moisture barrier.

The easiest DIY solution (that I think would look decent) would be to get some (gel) wood stain in the closest color you can find to touch up the scratches then remove the handles and do two coats of (satin finish) polyshades in a color slightly darker than the doors are now (probably bombay mahogany).

A 2015 consumer study posted 68 different flooring products that were tested and LL's products at that time were 100%.Regarding the installation, the pad that you can use under click lock LVT should be no thicker than 1.5mm and 1.0 would be better depending on the locking system(some are stronger than others).

The sides were cracking, so we broke them out, inserted bars, re-poured and then put a skim coat over the tops, if that makes sense.

Would prefer a textured concrete coating but they all seem rather expensive for not a lot of coverage.  

I have used closed cell commercially but it has had a fire retardant coating added to the top of it to be left exposed.     

Somebody put a light coat of plaster over the poured concrete, and then painted that a light pink color. 

@James HamlingSo you use solid hardwood on the stairs and coat with 2 layers of poly?