The supplier of the stone, told me I would be better off buying premixed scratch coat than mixing the sand and mortar. I asked which should I buy, since the only premix I could find was type "N". Manufacture instructions call for type "S". He told me to buy the "N". I know that type "S" is higher compression than type "N", but will it really matter that much on a small wall? I plan on using type "S" for my application of the stone and the joints.

 

I think the stone supplier was looking out for you. Type N mortar is generally more workable, which would make it easier to get a good job. The materials are more important for an amateur. A good craftsman can get a good scratch coat using almost any type of mortar.

Strength is not a factor - period!!! It actually may be hindrance since the lower strength mortars are usually more elastic and not as brittle.

If you are using a Type N mortar made from a mixture of portland cement, the higher lime content in a Type N mortar increases the ability of the mortar to heal and gain strength through the long term process of carbonation. This is not a big factor, but just an interesting item.

Your main concern is the right type of mortar, so go with the suggestion of using a type N.

Dick

 

Thanks Dick! Music to my ears. It was easy to install, although I didn't get quite the 1/2" in some areas that they call for. All in all, I understand the reasoning, and very much appreciate your expertise. Thanks again.