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QuestionWhats the best lime mortar mix to use when stone walling?
I usually use 6 sand, 1 cement and 1 lime. You can play around with the sand and use all building or sharp sand or mix three and three. The key is that its a 6-1-1 mix. A mortar mix should never be stronger than the product it is bonding and stone tends to be quite soft compared to brick and block which is laid with a 5 and 1 mix normally. The lime adds some flexibility. Hope this helps.
R.Hughes Building and Conservation Ltd 1st Aug, 2011
Hi in response to your lime mortar question i would be using a NHL(natural hydrolic lime)3.5 or 5.0 depending on the type of constuction and situation ,mixed to a ratio of 1 part lime to 3 parts sharp sand or coarse building sand.On no account would you add any cement.The lime mortar also needs "cherishing" ie protecting from the elements with a damp hessian covering for between 3 to 7 days for it to "cure" keep the hessian damp for the duration.Hope this helps.Darren shepherd cscs gold card holder heritage skills.
shepherd&co 2nd Aug, 2011
When taking on a project like stonewalling for instanse ,You can use a lime mortar mix ,if you want ,or if specified by ur architect , but you, [can use sand and cement] ,as long as you use a weaker mix, say a 6 and 1 ,[ 6 sand and 1 cement],so if there is any movement ,the movement will occure along the morter joints ,and not the brick or stonework.Gowrie ,or just normal sand is optional .your builders merchant will point you in the right direction wen it comes to whatever cement and sand u should use .using a little fairy liquid will make your cement spread a bite more evenly ,and should be more plyable ,its usually only used on brick or blockwork ,but works well for an even bed for stone work also,as long as ur mix isnt too wet in texture .
robert w watt 1st Nov, 2011
Spot on Darren, 3.5 should be fine for all but retaining walls, but again it depends on the stone being used, and the exposure to elements. Suggest raking and pointing 3/4" with a stronger mix, (include cement in the pointing if extreme exposure),and be prepared to regularly re-point.
bricky1 6th Nov, 2011