CHICAGO | General Discussions

[LouisVanDerWright]

^^^ Either type will work, type O is basically what they would have used for everything 100 years ago. But it's very soft and doesn't need to be THAT soft. So it's OK to have a small amount of Cement in there and go with N.

For my buildings I use Type O when it's just patching empty joints. It cleans up better and is super easy to work with. If there lintel work, rebuilding, grind and point, then yeah, N is probably better because it's a bit stronger and you want to really glue any bricks you loosened up tightly in place. O is nice because you can just smash it into the joints and still broom it off 30 min later.

[Rizzo]

I’m inclined to say a permit is required for masonry repairs in this case because it’s a landmark district. Just about everyone else wouldn’t need one if they aren’t obstructing public ROW and creating a mess.

[BrinChi]

Originally Posted by LouisVanDerWright

^^^ Either type will work, type O is basically what they would have used for everything 100 years ago. But it's very soft and doesn't need to be THAT soft. So it's OK to have a small amount of Cement in there and go with N.

For my buildings I use Type O when it's just patching empty joints. It cleans up better and is super easy to work with. If there lintel work, rebuilding, grind and point, then yeah, N is probably better because it's a bit stronger and you want to really glue any bricks you loosened up tightly in place. O is nice because you can just smash it into the joints and still broom it off 30 min later.

Sorry to revisit this topic again, but a preservation-minded neighbor just stirred the pot by steering me away from Type O/N mortars, introducing me to Hydraulic Lime mortars. Referenced this site: https://hfsmaterials.com/restoration...e-mortar-tips/
Purportedly, the Naturally Hydraulic Lime (NHL) products are breathable enough to release moisture and eliminate effervescence.
Is going this route more than what is necessary, especially if it's unlikely that a building doesn't currently use an NHL mortar?
I can't wait to hear from all the experts here.

[Rizzo]

Originally Posted by BrinChi

Sorry to revisit this topic again, but a preservation-minded neighbor just stirred the pot by steering me away from Type O/N mortars, introducing me to Hydraulic Lime mortars. Referenced this site: https://hfsmaterials.com/restoration...e-mortar-tips/
Purportedly, the Naturally Hydraulic Lime (NHL) products are breathable enough to release moisture and eliminate effervescence.
Is going this route more than what is necessary, especially if it's unlikely that a building doesn't currently use an NHL mortar?
I can't wait to hear from all the experts here.

Maybe. I have used a general purpose hydraulic lime mortar for the common walls. So it flexes and self repairs. You can see where past contractors used something wrong on a newer wall made of reclaimed common and it’s already disintegrated at the joints. So your neighbors advise for NHL mortar seems great for common, but I’d be worried about using it on facade brick which may be more rigid and require something else.

I think it’s worth calling the manufacturer to discuss how the product would work.