Making Roof Shingles
( Originally Published Early 1900's )
SHINGLES.—To Make Fire-Proof and More Durable.—The Scientific American says: "Take a potash kettle or large tub, and put into it 1 barrel of wood-ashes lye; 5 Ibs. white vitriol, 5 lbs. alum, and as much salt as will dissolve in the mixture. Make the liquor quite warm, and put as many shingles into it as can be conveniently wetted at once. Stir them up, and when well soaked (say 2 hours) take them out and put in more, renewing the liquor as necessary. Then lay the shingles in the usual manner. After they are laid, take the, liquor out that is left, put lime enough into it to make whitewash, and if any coloring is desirable, add ochre, Spanish brown, etc., and apply to the roof with a brush or an old broom. This wash may be renewed from time to time. Salt and lye are excellent preservatives of wood. It is well known that leach tubs, troughs, and other articles used in the manufacture of potash, never rot. They become saturated with the alkali, turn yellowish inside, and remain impervious to the weather."
Remarks.--W here no wood-ashes are to be had, potash, or the concentrated lye for soap-making, 5 lbs. would be equal, or probably half stronger than the wood -ashes lye, as above given. Of course, putting the shingles loose into the mixture, takes up twice as much fluid as to put the butts in up to the hand, as sometimes done, and does not increase their fire-proof, nor lasting -qualities. The dryer the shingles the better will they absorb the mixture.