P. Langan Construction focuses on redwood fences , redwood decks , trex decks , retaining walls ,artificial turf ,stairs, flagstones, brick pavers, brick walls and concrete. Established in 2003.P. Langan Construction is a full-service general contractor that builds decks, patios, fences, additions and more for residential clients in San Francsico. The company is known for building with redwood, but it can work with most types of woods and materials, including Trex, Ipe and pressure-treated fir.