Abstract: A building wall or roof is formed of tubular structural members arranged in parallel, planar, spaced-apart relation. Saddle-shaped structural members having strengthening portions are respectively mounted on the tubular members with a clearance space, and thermal and/or acoustical insulation is interposed in the clearance space between the strengthening portions and the tubular members. As compared to conventional tubular log structures, the resulting wall or roof is resistant to horizontal forces generated by the wind or earthquakes and is faster and easier to construct and, furthermore, considerably better performing in terms of thermal and acoustic insulation without having to increase its thickness on an otherwise proportionate basis.