Adjustable pergola

A louver type roof structure including a plurality of elongated parallel slats mounted on slat hinges pivotally supported on carrier beams transverse to said slats so that said slats are pivotable between a closed position in which said slats lie roughly in one plane and their longitudinal adjacent edges overlap each other with respect to said plane, and an open position in which said slats are spaced apart, said slats having an upper surface facing the sky in said closed position, and an opposite lower surface, said slat hinges being mounted to said slats at said lower surface, wherein said slat hinges allow pivoting of said slats between said closed position and an extreme open position by an angle of at least 90°, said plurality of elongated parallel slats arranged in one or more subsets of slats, the slats of each subset being simultaneously operable, said roof structure further comprising a border slat disposed adjacent an end slat of said one or more subsets of slats, the border slat mounted to a linearly sliding hinge having a linearly sliding pivot point, said linearly sliding hinge and border slat, linearly slideable with relation to said one or more subset of slats in a confined track between two positions so as to allow the border slat to retract from a first position to a second position, away from the end slat, when the end slat is turned from a closed substantially horizontal position to an open upright position, allowing the end slat to reach the extreme open position the linearly sliding hinge being coupled to a spring that urges the linearly sliding hinge to the first position when not forced to retract by the end slat.