In Singapore, it may be interesting to note that all Conservation Work are governed by Guidelines set by the URA. Only Professional Architects and Engineers are allowed to carry out Conservation and Restoration work to Buildings.
As a layman, it may be interesting to read how much professional efforts had been put in to plan, to study, to comply, to execute to make Conservation / Restoration work a success.
The end result : a beautiful piece of Architecture Reborn to last another few hundred years.
Matilda House / Atreasuretrove Club House.
For reading and for general knowledge goto :http://www.thehomelook.com/resources/tools/tool-ura-guidelines.pdf