Flagstone mortar completely gone where it meets concrete

[dconner]

Hello all,

I have been scouring the website for ideas but can't find the exact answer anywhere. Around our pool we have a concrete deck (about 4 foot wide) and then around the concrete the previous owners installed flagstone which was mortared into place. Obviously the contractor who installed the flagstone did not take into account the expansion of the concrete as now everyplace the concrete and flagstone meet, the mortar is cracked and/or completely gone. Any advise on how we can step in and repair this problem? Been considering just adding new mortar and hoping it lasts. Or should I attempt to add a small expansion joint, or using some type of elastic type product in place of the mortar? I will try to get some good photos of this tomorrow and post them.

On a second note, the pool builder also didn't install an expansion joint where the concrete meets the brick coping around the edge of the pool and there are several spots (mainly the corners) where the coping has come loose. The bricks are still in place just very loose. Any advise on an easy repair for this that I can do myself without the need for hiring a mason. Sorry for the multiple questions under one post, just wanted to get both of those out there. I should also state that my wife and I probably won't be living in this house for more than a couple more years and don't want to break the bank on the repairs.

Thanks in advance!

 

[duraleigh]

If those gaps where the grout is missing are around 1/2" or less, I would probably use polyurethane caulk. It will flex fairly well and will probably look just fine after it weathers out in a month or so. A pic or two would likely help.

 

[dconner]

Overall photo to get and idea what we are looking at. Note the flagstone around the outside of the concrete. And please ignore the nasty water line, still haven't gotten to clean it since opening it.


Please ignore the dirty concrete, still need to get that cleaned up. But here is where the mortar is basically gone.


This is most of the grout looks now if it is still in place.


Larger cracks in other places.


Can see the expansion or contraction of the concrete here.


Lastly, although I didn't originally ask about it, any idea on what type of paint this is? Looking to repaint it this summer as its chipping pretty bad after the amount of snow we received this winter.


Thanks again!

 

[JamesW]

Ideally, an expansion joint should have been put in between the concrete deck and the brick coping and between the concrete deck and the flagstone deck.

Without an expansion joint, the mortar securing the coping will eventually all fail prematurely. You could saw cut in an expansion joint to help prevent further damage. However, that would cause more problems, as you would probably end up needing to redo a lot of the brick. Therefore, it's not an easy choice.

If almost all of the bricks are secure, then it would probably be worthwhile to cut in an expansion joint and caulk. As long as the bricks are well secured, you should be able to saw cut in an expansion joint without loosening the brick. If you tap lightly on the top of the brick with the plastic handle of a screwdriver, you can tell which bricks are loose and which are secure.

If a lot of the bricks are already loose, then it might be better to wait until you're ready to redo all of the coping.

If the loose bricks pose a safety hazard, then they should be redone.

It might be worthwhile to cut in an expansion joint between the concrete deck and the flagstone deck. Besides providing expansion control, a clean cut joint can be filled evenly and made to look pretty good. There are colored caulks that would work well for filling in the expansion joint.

Note: Saw cutting concrete is not an easy or fast job and will be a fairly large task. You would have to decide if it's worth it to you to do.

The easiest solution would be to remove all of the loose grout and regrout or caulk as needed.