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Phil, Mechanical Engineer
Category: Home Improvement
Satisfied Customers: 8429
Experience:  Retired contractor, 51 years experience
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I have a 50 year old flagstone patio that I need to regrout.

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I have a 50 year old flagstone patio that I need to regrout. Some of the stones are uneven. How and how much of the old grout should I remove, what should I use to grout and is it possible for me to re-level only the stones that are a bit off by using some stone dust?
Welcome to Just Answer!

I will stay with you until the situation resolves. I hold questions open after positive ratings to allow for unlimited follow up.

Remove any loose stones. Use a heavy hammer and cement chisel to remove the ground from under any loose or uneven stones... apply new grout under the stone and level it.

You can rent a grout saw at a tool rental for removing a half inch of the existing old grout.. then apply the new grout over the top of that... then after it sets, but is not solidly cured yet, use a water hose and a broom to sweep the surface and clean the ground off of the stones.

Don't use stone dust to level the stones, they need to have a solid base of grout under them. Follow the directions on the dry mix bag of grout you buy to do the job.

Stay in touch as you need to. We can go from there without any time limit as long as you keep rating my advice positively.

Customer: replied 4 years ago.

Hi Phil


Thanks for the quick response. I'm going to have follow up questions but we've had A LOT of rain where I am and will have more rain for the next I haven't been able to really survey the work area since your response.


I have noticed a couple things though:


- The grout is either missing in most places or coming up in chunks so removal should be easy...but there's nothing underneath to 'bond' with. It's a patio at the side of a clay tennis court so there is mostly red clay and/or dirt under the old grout and the space goes down 1-2" from what I see so far. Would I just scrape out as much as I can and try to scrape under the stones a bit and fill with new grout?


-There are several broken pieces but I was thinking of just cementing these back in with the grout (instead of cutting new pieces and going to that level). What do you suggest on that?


Also, I'm new to this forum so am I supposed to rate you now or when this is done? I didn't want to 'close' this communication by mistake.


Do you know know if we can post pictures?




Hello again Allison!

You can post pictures by using the paper clip tool in this dialog box. If that fails you can post pics to a web site and just post the URL address to them here.

However I can tell pretty much what the problem is from what you have described.

I will offer a full range of solutions just to give you an idea of what your options are:


1. Remove all of the stones, chip the grout off, then re-lay them, each one in a few shovels full of cement then work the stone down into the cement until it is level with the straight edge you will be using to insure that the finished surface is level.

Then grout between the stones. So that the finished product has a 1 or 2 inch thick cement 'slab' under it. That will last quite a while.

2. Just replace the missing grout, scrape underneath a bit as you have mentioned, and re-level the stones where needed. This will not last as long, but will be a lot easier than option number 1.

You can just fit the broken pieces together, I would leave at least half an inch between them however, and fill that gap with grout.

You can rate my advice now. If you rate it as excellent I will hold the question open so that you can follow up as the work proceeds, all on the same dime so to speak.



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