Shower walls and ledger

[joengn]

Had success remodeling our 1/2 bath so I moved onto the full bath. Relatively handy guy but this is my first house so I'm still learning. I'm replacing all the 'fixtures' in our full bath and putting down a new floor and have a quick question. I removed the vanity, toilet and then the tiles and old avocado green cast iron bathtub with relatively no surprises (taking the sledge hammer to the tub was fun -- yes the new one will fit in the door/bathroom!). The water lines are all currently capped off. The bathtub sits adjacent to an exterior wall, all of which are constructed of concrete block covered in plaster. Some of the plaster was falling down because there is a window there that must have leaked and so when I removed the tiles the plaster under the window was just powder. I'm having the window (along with all the others in the house) replaced Wednesday. So here's my two main questions:

1. There was no ledger supporting the old tub, just 2 or 3 1x1's sitting on end, nailed to the wood floor. Do I need to put a ledger on the wall (after leveling the new tub) and if so should I just attach it to the walls with tapcons? Or are the 1x1's sufficient for the new tub (which I expect to buy an acrylic/lighter tub).

2. I've knocked off all the old plaster that was loose but there is a significant amount left on two of the walls, along with old glue from the tiles. Can I put cement board on top of all this with construction adhesive and tapcons? It would be a very daunting task to try and get all that plaster off because what is still remaining is attached very well. I did a ton of other small plaster repair jobs in the house the turned out good but I'm not sure of the best way to do this one.

Never posted here but I'm looking forward to starting some conversations! Thanks in advance for the help!

Joe

[HayZee518]

sounds kind of odd that a finish wall would be installed right on the concrete block! usually there is a 2X4 frame along any outside wall of block or even brick! A ledger board of some thickness would be helpful for the new tub as there isn't much support under the lip. Most of the weight would be on the floor. The ledger would just give stability to the tub. I'm still thinking of infiltrated moisture through the block to the inside of the walls - doesn't sit right with me...

[joengn]

I suppose thats a possibility. I could put up some sort of moisture barrier or coat the cinder block walls (provided I get all the old plaster off). There's a lot of chipping in my future if I need to get all that old stuff off though. The area where it was loose/powdery was right under the window in the shower which is why I suspect leaking rather than infiltration. But I am no expert thats for sure.