hydraulic lime verses non-hydraulic Lime

[tumbledown]

Has any one any experience of using hydrulic lime? I've been reading a few articles about it, and it seems it might be better in certain circumstances for render and pointing - for example, on very exposed surfaces, or where an area is subject to getting wet a lot ( I was thinking of my brick plinth along the pavement that gets plahed a lot by cars going past).

could it be used for grouting flagstones making it a little easier to wash without dragging the line out? (my wife is a cleaning- addict!)

 

[Ian Bond]

I used St Astier NHL5 strong hydraulic lime for bedding my stone roof ridge tiles. It seems OK.

I'm *still* trying to get around to the chimney stack repair, and I'm going to use a moderate NHL 3.5 for that. Hedging my bets between NHL 2 and 5 here.


http://www.stastier.co.uk/index.htm?nhl/data/nhl35.htm~rbottom

NHL5 would be OK for building canal walls, so should withstand a regular scrubbing

However - I use fat limes (non hydraulic) for everything other than roof and chimney repairs, and I'd use the non hydraulic for laying flags too - inside and out.

Are these flags indoors, and just going to be subjected to a gentle mopping?

 

[tumbledown]

Well, knowing my wife, the mopping won't be all that gentle! I just didn't want to be re-grouting every five minutes. However, I gather it is not as breathable.

 

[Ian Bond]

In that case, I'd use the non-hydraulic mortar for pointing the flags, and go easy on the scrubbing.

My stone flag floor has been much abused, and spent many decades under carpet / cement etc.

The pointing needs repairing in places, but I'm not going to be too fussy about it - all part of the rustic charm of the old place.

 

[Gervase]

It's not as breathable. And, to be honest, I wouldn't bother with it for grouting flooring. Stick with ordinary fat lime and save the hydraulic stuff for outdoors. Where you do need it is for the top coat of render or roughcast on exposed walls, and for the reveals around windows.