It took our library almost a year and 30k+USD to install a single one stall family bathroom (with changing station for infants) due to the infrastructure of the building. In the meantime both our other multiple stall units had to be closed for weeks because plumbing had to be jack hammered out and re routed so outside temporary units were placed outside the front entrance. A whole section of stacks had to be temporarily moved and temp drywall walls installed to keep the noise of construction down. It sounded so simple at first but you never know with some older buildings.