We are looking to put an offer in on a house located in Austin Texas. Before we take the plunge we want to know what it would cost to add a 1/2 bathroom. The home is on a slab foundation. We would be adding the bathroom to an existing space, about 6 feet away from the existing bathroom. The plumbing would need to extended across the floor of the existing bathroom and into the wall of the new bathroom. Is there a general formula for figuring out the cost for this? I was told that square ft of proposed bathroom X $200.00 is a rule of thumb when dealing with a slab foundation.

Thanks for all thoughts and info.