Historic Preservation

Preservation Trades Network (PTN)
The Preservation Trades Network (PTN) is a non-profit membership organization dedicated to education, networking and outreach for the traditional building trades and allied disciplines in the conservation of the built environment.
https://www.ptn.org/
Sanrakshan Heritage Consultants
Business, Construction and Maintenance, Historic Preservation - Sanrakshan Heritage Consultants. A cultural heritage management firm in India specialising in the architectural conservation and management planning.
http://www.sanrakshan.com
Hockley & Dawson
Business, Construction and Maintenance, Historic Preservation - Hockley Dawson. Consulting engineers who specialise in the sensitive repair and conservation of historic buildings and structures.
https://hockleyanddawson.co.uk/
Building Conservation Associates Inc.
Business, Construction and Maintenance, Historic Preservation - Building Conservation Associates. A private consulting and research firm practicing preservation design, conditions assessments, materials science, and historic building documentation.
https://www.bcausa.com/