Try to position the site office in an area with limited access for the opportunist thief.
Office equipment such as fax machines, computers and telephones are all expensive and can easily be stolen if not properly secured. They should be well marked with indelible marking - for example by branding the company logo and postcode onto the equipment.
Also consider protecting valuable business information. This could include payroll figures, work schedules and future ventures, or anything that could undermine your company strategy if it was lost or put in the hands of rivals.
To discourage theft, you can permanently mark your company's property for quick visual identification. Stamping, etching, engraving, sandblast marking, acid pens or ultraviolet lacquer can be used.
