In article .com,
wrote:
Also, out of interest: If the cement and the grout were waterproof,
would the original solution (using porcelain tiles) not provide a
waterproof covering? How would this likely fail?

Because the roof isn't rigid and will move with heat, etc. As will the
tiles.

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*Why don't sheep shrink when it rains?

Dave Plowman London SW
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