The Louvered Penthouse with closed corners is available with or without stormproof deflectors (as used for mechanical evacuation). The Penthouse Ventilators are built in sizes varying from 4 ft. x 4 ft. up to and including 6 ft. x 6 ft. Such characteristics as the quantity of louvers, the type of metal, the total evacuation, the steel gauge (maximum thickness 1/8 in.) and all the dimension of the penthouse can be modified to suit your needs. Special flashing can be built to suit all types of roofs. Different types of louvers to prevent infiltrations are also available on request. Do not hesitate to send us your specifications or needs. When specifying the size of the ventilator, always remember to calculate an allowance for the thickness of wooden curb and roof membrane.