Of this we speak with the advantage of many years’ experience as
practical roofers. The great difficulty metal roofers have to contend
with is contraction and expansion of the metal under the changes of
temperature. This cause alone calls for continued repairs in all flat
lock or standing seam roofs, and the seams underneath are receptacles for
any moisture which may condense on the underside of the metal. All such
roofs first show decay in the cross seams, and this, while the body of
the plates shows no sign of decay. Our shingles have no cross seam, and
are sufficiently ventilated to prevent condensation of moisture; while
a glance at their construction shows at once that the difficulty caused
by contraction and expansion is successfully overcome. Our shingles do
not require the skilled labor which is necessary to lay the flat lock or
standing groove metal roofing, while the time required to lay a given
surface is much less.
In estimating the difference of cost between the ordinary tin roofing and
our shingle, a steep roof house alone must be taken in consideration, as
our shingle is not proposed for a flat roof. (See “Comparative Cost,”
pages 26 and 27.)