Sliding patio doors can often be the weak link in an otherwise secure house. Be sure to use security bars for added protection on sliding doors and keep them locked when not in use. There are two primary types of security bars: one for standard doors and one for sliding patio doors. Look for a security bar with a patented locking device that can withstand up to 1,000 pounds of force. Patio door security bars should also prevent thieves from lifting the door off the track.