Most jobsite thefts are crimes of opportunity. Thieves target sites that make it easy for them to get in and get out quickly without being seen. BUILDER asked its readers, current and former law enforcement officers, insurance claim adjusters, manufacturers, and risk consultants for suggestions on how to reduce jobsite theft. The answers ran from lighting to hiring security guards. Here are five cost-effective responses:

1. Know whom you're working with. You may not be able to control every worker who walks onto your site, but you can control the trade contractors you hire. Make sure they have the proper licenses and insurance. Look for contractors whose workers are employees rather than pick-up crews.

2. Practice just-in-time delivery. A thief can't steal what isn't on the site, and he's less likely to steal an item that's installed. It takes longer than just picking up a box of plumbing fixtures or a stack of windows that are sitting in an open garage. Don't schedule deliveries on Fridays or the day before a holiday. A significant number of jobsite thefts happen over the weekend. All it takes is a weather delay for materials to be left sitting unattended for several days when the site is empty.

3. Secure your tools and materials. It's an easy thing to leave tools and materials in a house when you're coming back to finish a job the next day. Don't do it. Take them with you, or lock them in a jobsite box or trailer. If you do that, one reader suggests bolting equipment to the trailer itself. If you can't afford that, at least put them inside the house behind a locked door. Or try this reader's suggestion: Put materials on the roof of the house at the end of the day.

4. Lock up the house. Many builders leave their houses unlocked well into the building cycle, giving thieves easy access to strip the house and damage the walls and floors. As soon as the house is dried in, lock it up.

5. Install appliances and AC units at move-in. These two big-ticket items are prime targets for thieves, who often do tremendous damage to the house in the process of stealing them. Almost 50 percent of our survey respondents said they've switched to installing these two items when the buyer moves into the house.

Click here to see what jobsite thieves are after.