Style of House
Your house was built with a certain design and style in mind. The roof was or should have been chosen to suit the house. In saying that, an incorrect or poor choice could have been originally made.
An old Victorian style house could have had either a Terracotta or galvanized roof. When re-roofing, it would be silly to use a new concrete tile or bright Terracotta tile. The smart choice would be to go for a nice rich colour in the Colorbond range to suit your colour scheme, or pick a neutral / earth coloured Terracotta tile.
Frequently, the council will have the final decision on your roofing material. A house which has a heritage overlay, will most likely have to conform to guidelines requiring the roof to be galvanized. This is certainly true around suburbs such as Williamstown and inner city areas with a rich Victorian history.
When selecting your roofing material, there are structural factors that need be addressed. Are your roof trusses braced enough to support metal sheeting? This will need to be looked at when switching from a tiled roof to metal.
Is your roof and house support strong enough to support the weight of roof tiles? (Certainly never in the case where a metal roof has been the original roofing material).
In nearly all re-roofing situations, the battens need to be renewed also.
Obviously budget can also be a determining factor when deciding on which roofing material to re-roof with.
Changing a roof from roof tiles to metal can be a more expensive exercise than replacing with new roof tiles. Firstly, the roof tiles need to be taken off and discarded of which is time consuming and very labour intensive. Secondly, metal roofing (labour and material) is actually more expensive than roof tiling labour and materials much to most people surprise. The roof needs to be fully battened out using metal battens and an insulation foil to Australian standards needs to be installed.
A straight swap of any roof tile to new concrete will be the most cost effective option. The price increases with the quality of the concrete roof tile.
Terracotta tiles are slightly more expensive again. A natural or earth coloured tile will be the most cost effective with a fully glazed Terracotta roof tile being the top of the range and quite expensive.
So there are many options to consider when choosing your new roof. Your roofing professional should be able to guide you on these and come up a great roofing solution and colour scheme to suit your house and budget.