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1950-51 Theatre Catalog, 9th Edition, Page 111 (91)

1950-51 Theatre Catalog, 9th Edition
1950-51 Theatre Catalog
1950-51 Theatre Catalog, 9th Edition, Page 111
Page 111

1950-51 Theatre Catalog, 9th Edition, Page 111

panels absorb a considerable part of any sound. The percentage depends on whether standard, low density, scored or drilled board is used.


Insulation of the lamella roof can be effected in the same manner, and with equal force, as truss and rafter roofs by a simple application of insulation board over the sheathing, or to the underside of the lamellas.

Even greater effectiveness may be attained by applying insulation board inside the lamella panels. This procedure provides thin confined air blankets between insulation and sheathing which are sealed off against the lamellas by a continuous moulding (Fig. 6).

Heating. Ventilating. and Cooling

A forced air blower system and unit heaters, which can also be employed for air circulation, ventilation and cooling, have been found to accomplish the heating of lamella roofed spaces most effectively. Since it stands to reason that the insulation value of the surrounding wall and roof areas of a room govern the amount of heat loss which will have to be compensated for by the heating unit, a building with a buttressed lamella roof should be more economical to heat, or to cool, for that matter, than a building of similar proportions with orthodox roof construction for the same fioor clearances, of similar type wall construction and roof insulation.


It is possible to daylight lamella-roofed buildings by means of conventional windows set in sidewalls, large window areas in short-length constructions, monitors, ridge-type skylights, or corrugated wire glass expanses laid over portions of the roof network. By painting lamellas appearing in light-admitting areas white, light entering through monitors or skylights can readily be diffused over the entire floor area.

Artificial lighting conduits in buildings of a commercial nature can be run under the network or along the tierods in tied lamella roofs. When lamella roofs are to be treated ornamentally, it is advisable to run the conduits on top of the network, parallel to the sill, with sheathing boards

FIG. 3. Typical Lamella roof arches. Upper left:

FIG. 4. (Above) Variations in roof plan. (A) left, a continuous root. (B) right, a roof with a rattered end. Many variations are possible.

ripped to abutt the conduits. Gable walls will secret conduit risers and interconnections most inconspicuously. Outlet boxes should be attached to the underside of the sheathing (Fig. 6).

Wind Resistance

A lamella network forms a natural curved wind-truss spanning from gable wall to gable wall, thus permitting the walls to be designed as supported on top and bottom against wind pressure.

(A) Tied segmented arch. Lower left: (B) Buttress

segmental arch. Lower right: (C) Parabolic arch. Upper right: (D) Gothic arch.



FIG. 5. (Below) Variations in root plan. Broached ends may be rectangular or many sided as desired. Through this L. T or H shapes are available.

The curvature diverts, rather than blocks, the wind in the direction of the arch. It is generally accepted that the effective wind pressure against cylindrical objects, such as chimneys, tanks, and curved roofs, is two thirds of the wind pressure against a plane equal to the vertical projection of the curved object.

The relatively closely spaced lamellas permit frequent and efficacious anchorage of the roof to the sidewalls. Since all connections are bolted, a high resistance against excess interior pressure, due to winds or other causes, is afforded.


Due to the fact that shrinkage in wood occurs principally across the grain, shrinkage along the grain is minor. Since the grain of lamellas runs with the span of the roof, the possibility of settlement, due to shrinkage and slippage of bolts in one-sixteenth-inch oversized holes of joints, is very slight indeed, and any which does take place occurs over the entire roof area.

Across-grain shrinkage depends to a large extent on the moisture content of the lumber. Since only well-seasoned or kiln-dried lumber is used for lamellas, this factor is hardly worth serious consideration. Even during the war years, when only partially seasoned lumber could be obtained, roof contours showed few adverse effects. Bolts of common
1950-51 Theatre Catalog, 9th Edition, Page 111