I have recently purchased a semi trailer refrigerator unit that I am turning into a construction site office trailer. Since my practice often takes my away from home for extended periods I have a complete set of apartment furniture that I use for temporary work apartments plus all the office furniture and equipment needed for an site office.  I don’t intend to live in the trailer, just use it for storage and transportation of the apartment furniture to the job location and use the trailer as an office on site.

I feel that buying the old trailer (cost $6,000 CDN) to use for storage and as a site office will be beneficial.  I will recoup the cost in about one year on site usage compared to renting a traditional office trailer and transportation costs. I have the added benefit of no storage costs when I am between job sites. For example on my last site assignment it cost  $450/month to rent an office,  between $150 and 250/ month for the port-a-potty, almost $2000 mobilization in and set-up plus $1,500 to rent a U-haul to take the furniture home at the end of the job. Temporary storage costs would have been $100 per month or the loss of my garage. My costs with the trailer will be around $1 to $1.50 per mile to haul to the site and back. I am estimating complete set up costs at $12,000 to 14,000 (all prices $CDN)

The trailer came insulated and the refrigeration unit was removed. It has a metal liner. I will be installing lights, heating and air conditioning, cupboards for a coffee area network cables and telephone wiring for quick hook up at the job site.

I am intending to install a washroom (I hate port-a-potties in winter because of the cold and summer because of the smell), complete with shower (usually emergency use only) and internal water supply system. I’ll use low water volume toilets and also install a urinal for water conservation reasons. Waste, I am not sure about as I may be able to dump direct to a manhole or have to have a septic tank either on a trailer or use a local service to empty. I will probably not address this issue until I am on the first site and see what is available.

I’ll have all the computer system wiring on a power protection system (UPS for computers plus surge protectors for printers and communication wiring) I have sent several e-mails to various manufacturers asking them to recommend a product. I would like a single system hard wired into the panel and have the capability of shutting down the PC’s on a power failure. Anyone have any ideas or recommendations in this area? (3 or 4 PC’s plus printer plotter scanner etc)

For power I will have a weatherproof box installed under the trailer with a bus bar for site connections. I will also install a second box for a power connection for a second (contractor?) trailer.

I’m not sure about the heating and cooling system. Due to the size of the trailer and insulation levels, the smallest furnace available is more than adequate. (less than 30,000 BTUH) I will be installing both electric and propane heating as some sites will have enough power for electric and some will need propane heat. I am thinking about a through the wall type of high efficiency heater, but have no direct experience in these units. I do not want to use window air conditioners as these are too noisy for an office environment.

I have also thought about using a horizontal dual supply (propane/electrical) system installed under the floor of the trailer. (there is 750 plus mm available without being concerned about ground clearances). I would then have to make the complete system weather proof and protected structurally for transportation.

Anyone have any ideas in this area?

Any comments or suggestions would be appreciated.
Feel free to steal this idea.

Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion
www.kitsonengineering.com