Hi All, Planning an extension to my house and want to establish an accurate way to calculate pitch and rise. Current roof on house has trusses that measure 6.6 metre's span (outside of top plate to outside) and a rise of 720mm if you measure from top of truss to underside of bottom chord. I always thought you could calculate by dividing rise by the run so in above case that would be 720mm minus 95 for bottom cord = 625mm then divide this by run 3.3 equals 189mm which I assume is rise per metre....

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