# Need Advice Regarding Proper Grouting Between Bluestone On A Outdoor Terrace



## coollx (Apr 25, 2017)

I'm helping a dear friend select a mason contractor to repair her bluestone outdoor terrace and I'm looking for some advice.

We live in Upstate NY where we get pretty severe winters with a lot of snow and freezing conditions.

Her terrace is about 250-300 square feet and is covered with large, though random sized, pieces of square precut 1"-1 1/2" thick bluestones. 

The problem is that a previous contractor ground out the grout lines between all the stones and filled the grout lines with a product that turned to a powdery consistency within 12 months and she wants to have it repaired properly.

I'm a fairly experienced DIY but not a mason and agreed to help her talk with and obtain repair estimates from experienced masons who she hopes to contract to complete the repair.

Yesterday, we met with a masonry contractor with 30 years experience who if she hired him said he would grind out the grout lines down to the base which is a poured concrete slab. He said he would then fill most of the 1" - 1 1/2" deep grout lines with masonry cement or sand then put TILE GROUT on the top 1/4"-1/2". 

We questioned the use of tile grout because he's the first contractor to suggest using it but he said he has found that tile grout bonds extremely well to the blue stone and will not crack or separate and will seal the joint to prevent moisture from getting under the blue stones and disrupting the bond between the stones and the concrete base.

My question to people on this forum experienced with outdoor masonry, is this guy a crackpot or is he a visionary who is ahead of his competition with his approach?

I would appreciate your comments and suggestions so I can help my friend.

Thank you

Dom


----------



## stadry (Jun 20, 2009)

tile grout's an interior mtl in binghamton,,, not exterior imo up there,,, repoint w/mortar & isnay on grout,,, if he's from john garbade's shop, i'll revise my opinion


----------



## jomama45 (Nov 13, 2008)

I've always used a masonry mortar that is heavy on Portland cement for this type of application, whether it be Bluestone, flag stone, or clay brick, with great success. Usually about 75-85% Portland to 15-25% lime, and mix that blend to 2.5-3 parts mason sand. It helps to keep it damp for a few days to control the shrinkage.

Can't say I've ever heard of tile grout, but that doesn't necessarily mean it won't work either.


----------

