About Us

Sentinel Structures, Inc. manufactures structural glued laminated timber, mass timber, at Peshtigo, Wisconsin. This is site of the original timber laminating facility in North America, established in 1934. This is experience with no equal. All products are custom made for the particular application – from straight beams and truss members to curved arches; the great and compass engineered timbers for use in roof and floor construction in buildings; electric utility towers; decorative lighting standards; wooden boat and ship framing; highway noise barriers; pedestrian and vehicle bridges; sculptures; and many other items.


Many are aware of the great Chicago fire of October 8, 1871. Few are aware of a far more disastrous fire the same day in the great pine forests three hundred miles north of Chicago, at Peshtigo, Wisconsin. The lives of 600 in Peshtigo were lost and many more perished in the surrounding timberland.


William B. Ogden, first mayor of Chicago, owned the Peshtigo Company at the time of the fire. The plant consisted of a sawmill, a woodenware factory, a sash and blind factory and loggers in the woods, employing 800 persons.   

Wood has been used for fuel, for housing, for transportation, and countless other end products. Today, the market for structural glued laminated timber is in buildings, bridges, sound barriers, and a myriad of other uses. While wood still serves as fuel, there are far more important uses in structural applications. 

The first structural glued laminated timber members in America are roof supports in the Peshtigo High School gymnasium, built in 1934. The base facilities of Sentinel Structures, Inc. are those used by the 1934 company to fabricate those first glued laminated timber arches. 

Markets for structural glued laminated timber have expanded dramatically since 1934. Board footage in excess of 300 million is laminated each year by the industry into columns, straight beams, pitched and curved beams, curved arches, and parallel, pitched, and curved trusses. These wood members normally use untreated wood but use pressure preservative-treated wood when fully exposed to the weather without roof cover. There are places where untreated wood is used under roof cover, but in such enclosed areas having excessively high humidities for extended periods of time, proper ventilation is then required to control humidity and the wood moisture content.