What mortar mix for a fireplace

[RichD1]

Replacing our fireplace with a Victorian cast iron type. The front hearth will be a granite slab but not under the fire grate. This will be cemented, but what mortar mix should I be using?

Richard

 

[dontbelieveawordofit]

is it a working fire?

 

[RichD1]

From time to time, probably around Christmas time.

 

[23vc]

Just a sharp or building sand and cement mix, it’s not directly in contact with the fire and sits below it assuming you’re having the usual fire insert and ash pan

 

[dontbelieveawordofit]

yep 4:1

 

[RichD1]

Sounds a bit strong, or is strong better for heat?

 

[Wayners]

Just under 6-1 with a splash of ad mix. Would not go under 5-1.
Will give a bit and plenty strong enough and keep sand colour. 4-1 will be gray