The spruce-pine-fir (SPF) group is a mix of Engelmann Spruce, Lodgepole Pine and Subalpine Fir. SPF has a high strength-to-weight ratio and is primarily used for framing in North American housing. Due to its dimensional stability and superior gluing properties, SPF is used extensively in the flat-packed furniture industry. It is also a great choice for modular houses, interior finishing, boxes, pallets, packaging cases and concrete formwork.