replying to biff, chris wrote:
silica sand is glass, used for ashlar . sharp sand contains glass but a not
as much. 3:1 ratio is okay for walls and low level renders/pointing. exposed
areas need something stronger. 2.2:1 lime to sand ( add a tiny wee bit cement
to the mix ) any st astiars nhl (except 5) will work greatly. you can buy pre
mix 25 kg for £12.50. fine sand or coarse ( fine for pointing/rendering less
than 5mm) . just add water. adhesion is exceptional and it sets very
quickly. its bombproof!!! otherwise general building ...... sharp, sand,
tradiblanc nhl (35 kg) but be aware, tradi sets very light so use a dark sand
or add pigment and defiantly carry out a wee trial.patch

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