expansion joint - caulk? grout? neither? makes no difference?

[engrav]

Old pool with expansion joints between coping slates and deck slates and various other places.

Have obtained various opinions as to cover the joints with caulk, grout, nothing, or makes no difference.

You all would recommend?

Thank you

 

[JamesW]

Caulk is the way to go. Grout does not allow for expansion. Doing nothing allows water to get in, which can lead to erosion and ice damage.

 

[engrav]

Thank you

 

[OIM]

When you clear out the old material from the joints. Take a look at the depth and even try to measure it. Some backer rod going in before your caulking will be very helpful if none is there already. Also, try to use some self leveling caulk. I use Adeka P201, but it is a bit overkill for decking expansion joints. Of course, I'm assuming you are redoing the joints entirely. You may have already been up to date on this just thought I'd mention it. Good Luck!

 

[engrav]

Thank you. Will check out Adeka.