Balconies or decks can be constructed in many ways, the construction method chosen will determine what type of membrane you should use. In some cases liquid membranes will be fine and offer long term waterproofing reliability, structures that could be susceptible to movement and exposed to high temperature extremes could have a sheet membrane such as Strataflex installed to the substrate, Strataflex can handle up to 9.6mm of joint movement.
Flexitray highly recommends all balconies of lightweight construction use a compressed cement sheet substrate, installed to the manufacturers specifications, plyboard is not considered a reliable alternative. Tile underlay or cement sheet nailed over a substrate will not be considered suitable for membrane.Concrete balconies are generally less prone to movement.
Flexitray will install the membrane we consider appropriate for the structure and site conditions, price should not become the deciding factor at construction stage, the builder should be confident the best membrane has been installed to handle the conditions, rebuilds at future dates are extremely costly.