Waterproof covering and process of making same

Application filed May 28,

Among the salient objects of this invention are to provide a product which while made of very thin caliper felt is nevertheless particularly characterized by its B strength and stiffness; to provide a product which has a minimum amount of the expensive fibrous constituents, and a maximum amount of the relatively cheap grit and asphalt constituents; to produce a product in 10 which the saturated felt is advantageously made by my novel process of forming waterproof paper such as set forth in my pending application, Serial No. 339,690, filed Nov. 21, 1919, but which if desired can be 15 made from ordinary felt; to produce a product which because of the very thin caliper felt, can be made from fibrous constituents other than rag stock, as for example, mixed papers; to provide a product formed of plies 20 between which is embedded grit such as crushed gravel, quartz, bricks, tiles or the like cheap waste material or cork, sawdust, limestone shells or the like; to produce a product particularly adapted for roofing 25 elements as strip shingles, or the like; to provide a novel process for producing this product and in general to provide an improved product and process of making same as referred to.

SO Fig. 1 is an edge view of plies in position to be united.

Fig. 2 shows the united plies with the surfacing on the upper surface.

The process may be carried out as fol35 lows: Waterproof felt 1 may be formed in accordance with the invention disclosed in my said earlier application, or dry felt may be made and then saturated in the usual way. The caliper of this felt may be about 15 40 points. This felt is then coated with asphalt 2 and a grit surface 3 applied as in the usual way. This may be very cheap grit as color and appearance are of no importance. Two such sheets of this finished grit 45 surface roofing are brought together with their grit covered surfaces opposed. To one or both of the grit surfaces must be first applied a coating of hot asphalt or the emulsified matrix 4 referred to in said prior 50 application. These are then run between pressure rolls for the purpose of firmly uniting the two sheets with their opposed grit covered surfaces together. This forms a unitary structure of a sandwich like chares acter.

This structure may be then run beneath

1820. Serial No. 384,900.

a coating roll and one or both of the outer surfaces coated as shown at 5 and a granular facing 6 applied in the usual way. The sheet may then be cut up into shingles or eo shingle strips to form what may be called stiff sandwich shingles. The caliper of the finished shingle made in this way without the final coating and final granular facing may be as high as 60 to 80 caliper. 65 Instead of embedding grit or the like between the sheets, iron filings, short pieces of metal, wood or other reinforcing materials may be used. If desired, more than two plies may be united in this way and by 70 using sufficient number of plies, a built-up structure of tile or block like character can be made.

On account of this novel mode of uniting these plies with their grit surfaces opposed 75 and their particles interlocked, there results a high degree of structural stability which has not been possible to obtain in heretofore known felted roofing compositions. This construction lends itself especially to the 80 formation of roofing elements haying a surface other than flat structure, usual to prepared roofing. For example, it is possible to prepare a semi-rigid tile shaped element which will maintain a curved structure 85 similar to that of clay tiles and which will retain its original form under the influence of the summer sun.

The tile-like covering has the advantage of being somewhat resilient, and especially so adapted to withstand rough handling ijn transportation without injury.