When you select a SPF contractor it is best to know about the type of spray foam product that you would like to have installed. Contractors are typically selected to do installations in new buildings or to weatherproof existing structures to make them more efficient. New installations or large panel renovations typically use a two component high pressure system. The contractors installing this type of foam must be well trained and have the proper protective equipment to do the job. Most other jobs use a low pressure system that is still comprised of two components. This type of system is usually used for smaller jobs like weather sealing and filling small gaps or cracks. Both systems can use open or closed foam products. Each have their own benefits and drawbacks which are best discussed before installation. Always be sure your contractor is insured and has the proper training and equipment necessary to install SPF products.