Sunday, May 9, 2010

How Handy Is Sandstone?


Progress went well on the Saturday of the Frontenac Arch workshop. The sandstone turned out to be fairly easy to shape. The guys working on the project picked up the principles fairly quickly and were making some good structural decisions. The hearting is a bit of a problem. The sandstone we are using doesn't seem to be nestling or fitting into the spaces as nicely as we would like. It is abrasive and a bit brittle. It's turning out to be not that handy as for wedging either. The smaller pieces have much less of an ability to shim the bigger building stones, the way limestone or granite chips would do, and so to avoid the wedges getting crushed with the weight and pressure of the bigger stones we think that we should to introduce granite instead for the important pressure points. Apparently limestone pieces would not work in combination with the sandstone, as acid solutions that wash carbonates from the limestone can chemically affect the durability of sandstone.

I have not read anything that says granite and sandstone should not be used in combination, but if anyone has heard this isn't a good idea, please let us know. But for this project at least it's off to find some nice granite rocks to break up and make better wedges to work into the arch structure today. It's not like there isn't a lot of granite to choose from in the this granite epicentre of the Ontario, here at the Frontenac Arch Biosphere.

2 comments:

  1. Limestone/sandstone....Pah!!

    I have a photo somewhere of a tiny rivulet eroded out of a piece of sandstone by a drip from limestone above.... the wall was supposedly 200 years old, the rivulet an eight of an inch deep.
    In Yorkshire the Craven fault is a distinctive cleavage between Limestone and Sandstone, it is striking that 50-100 yards one side of a road its all limestone, 50-100 yard the other side its all sandstone, the bit in the middle is of cours various degrees of mix. Nothing really noticeable in condition of walls.

    Limestone will dissolve sandstone but this is such a slow process their are very few of us who need worry about it making our walls fall down

    Sean Adcock

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  2. Whether or not mixing stone types of very diiferent surface textures and/or shape is a good idea or maybe needs different techniques/application of techniques is another matter completely.

    Sean Adcock

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