Heavy timber construction

found: Work cat.: Heavy timber construction details, 1961:p. 3 ("Heavy Timber Construction is that type in which fire resistance is attained by placing limitations of minimum sizes on wood structural members ... by avoidance of concealed spaces ...")

found: Paul, C.E. Heavy timber mill construction buildings, 1916:p. 5 ("mill construction ... is the name given to that type of building construction in which the interior framing and floors are of timber, arranged in heavy solid masses and smooth flat surfaces, so as to ... avoid concealed spaces which may not be reached readily in case of fire")