I have a question. Will HDB allow a bathtub outside the confines of the designated toilet? I'm under the impression that such a design is unacceptable due to waterproofing issues. http://www.hdb.gov.sg/fi10/fi10324p.nsf/w/HomeRenoGuidelinesBuilding?OpenDocument#Bathroom Enlargement of bathroom/toilet after first three years upon completion of block Yes Maximum width and area of extension Must not be more than 600 mm and 0.6 m2 respectively and Can only be used as a "dry area" For example, for installation of wash basin or shelves The existing gas riser and it’s branch pipe must not become enclosed in the extended bathroom/toilet