Do adult sponges do not to attach themselves to hard servics underwater?

The answer isn't going to be a very specific one as it's more of an abstract idea. See most sponges are made of protein fiber strands kind of like threads. Many of the surfaces in the ocean are porous so sea sponges dont have a foot or anything like that, their bottom is made out of the same stuff that the rest of their body is made of because the fibers/threads can just web themselves onto the surface and attach by going into the pores for anchor.

Some sponges are able to attach to sediment surfaces like sand by actually growing a type of root for anchor.