KEEPING OUT IRE WATER

Evening Star, Issue 19642, 23 August 1927, Page 2

KEEPING OUT IRE WATER

Since the appearance in those columns a, few weeks ago of the article dealing with the protection of concrete and brick buildings the writer has been invited to test the waterproofing qualities of a number of compounds on the market. It is impossible here to mention trade names, but bo was particularly impressed by wlr • bo saw of one waterproofing substance that seems to do everything claimed for it. This is sprayed on the stone or brickwork, and evidently forms a covering film that has a different surface tension to that of water, and consequently all moisture is kept out. A drop of water placed on it will roll off like quicksilver. The writer has been given to understand that the architects for the new Town Hall. Messrs Mandeno and Fraser, lane specified its use for that big undertaking. Experiments were conducted with several porous materials, such as a Breeze brick, a. piece of plaster of paris, and a filter lop of Oainaru stone, each of these having been treated, Blaster of paris is particularly porous, and absorbs water instantly, but not the piece that “Stucco” saw yesterday. The water simply lay at the bottom of the small vessel used for the experiment, and was still there twenty minutes later. There was tho same story to tell of the filter top and of the brick. Another crucial test was the pouring of water in a small tin of Chain Hill sand, which, by the way. seemed to be more like small pellets than sand. The water remained in globular form on the sand, which showed that it was a question of surface tension, and not the mere filling up of pores. There seems to bo plenty of evidence to show that onto a building is coaled witli the substance the film remains on for an indefinite period. An important thing is that it is absorbed by the stone or brick, and, being colorless, it in no way changes the appearance of tho material.