I have 20 sites in the same domain, different niches and I want to interlink them for USER EXPERIENCE. I want to know from someone who tested this:

Will using a nofollow attribute for the links keep the sites safe from google link scheme penalties?


Question: Should I use cement board or green board behind the walls of a neo angle shower?
Answer: Always use cement board in a wet area.  Green board in the rest of the bathroom.
If you're using plastic or fiberglass panels you can use green board, but I would paint it with a waterproof membrane to insure the longevity.
You can search on the internet for names of membranes