What if the wooden support beams rest on a metal frame?
This is permitted since the metal frame is only a secondary support to the primary wooden supports. According to some opinions, this is true only if the wooden beams are actually assisting in the support of the s’chach (i.e. the removal of the wooden beams would cause the s’chach to fall down). If after removing the wooden beams the s’chach would still rest on the metal frame, the metal frame is considered to be the primary support according to this opinion. 30. May one tie or nail the s’chach to the wooden supports? One should avoid using string or nails to support the s’chach. If a person is afraid that the s’chach may slide off or be blown away in a normal wind, he should not tie or nail it down since this is considered a primary support. Rather, he should place heavy planks of wood or branches over the s’chach, since they qualify as kosher s’chach. The planks or branches may be tied or nailed down since the string or nails would then be considered a secondary support. Alternatively
