I've seen a few comments where a plumber mentions they use pipe before concrete then run the pex in the pipe. I'm interested in the idea since I will have no basement or crawlspace for access. I know it's common to run the water lines under the slab in alot of places, but I'm thinking of maintainability. This seems like a smart thing to do that doesn't add all that much to the cost of a house.
For those familiar with the practice, what is the most common way to branch to locations? Where would the manifold be located? Is this method only efficient with certain floor plans (consolidated wet walls, pipes in interior walls only, etc)? Does the method work better with certain types of foundations (slab on grade, stemwall with mono-pour, etc)? Stemwall with a mono-pour is common in my area due to sand.
Any help in understanding is appreciated, especially if there is example plumbing plan sheets!