Our shingles are not one-sixth the weight of slate, which greatly reduces the cost of the frame-work of roof. They readily conform to the shape of a roof, which slate will not do. Slate is not thoroughly fire-proof, as heat from an adjoining building on fire will cause the slate to crack, which would destroy the best roof in a few minutes, leaving the sheeting exposed. Especially is this the case if water is thrown on them while hot.
Our shingles are free from the many accidents to which slate roofs are liable, such as cracking from shrinkage of wood-work to which they are attached; breaking, caused by necessary repairs to the valleys or chimneys; and the effect of frost on defective slate. Such defects cannot always be avoided by ordinary observation. All builders of experience are aware of the expensive repairs necessary to keep a slate roof in good order, but perhaps the most inconsistent thing connected with the whole roofing business is the fact that nineteen-twentieths of all the houses covered with slate have gutters lined with the same material of which our shingles are made, while slate was used for covering because of its supposed durability.
Should anything fall on our shingles it would probably dent them without causing a break; but should it perforate them, the shingles can be replaced by another, or a leak can be soldered, and fire from an adjoining roof cannot more than injure the paint. They will cool off rapidly, retaining their shape.
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.)