Swimming Pool Coping and Decking
Bluestone, Bricks and Expansion Joints

by Preston Halperin
(Sudbury, MA)

Here's a question about swimming pool decking, coping and expansion joints.

I am about to build an inground pool and have conflicting advice from the pool builder and my landscape architect. The landscaper wants to use dry set brick that will butt up against bluestone pool coping. The pool contractor believes that backer rods and caulking is needed for an expansion joint between the brick and the bluestone. The landscape architect says he has used dry set brick against bluestone coping with no expansion joint. He says that the bricks have adequate ability to move since they are dry set. Your thoughts would be appreciated. Thanks in advance.

ANSWER

I agree with your landscape architect for the following reason.

Expansion joints are installed to allow large sections of concrete to expand and contract in various types of weather conditions. They are typically placed a particular distance apart. Forgive me, but I can't recall what the distance is, but that's not important right now. They are used where there are large areas of concrete, ie., sidewalks, stamped concrete, etc.

Bluestone coping does not even come into play since the pieces of bluestone are typically a couple of feet at the most. Even if they were larger, the expansion joints would be placed between the bluestone pieces every so many feet.

Although the bricks will but up against the bluestone, there will still be a space which will allow the bricks to expand and contract. Expansion joints are never used in dry laid hardscape applications. It is not necessary for there to be an expansion joint between the brick and the bluestone as it is not needed, and even if the bluestone had to move, it does have the room in that space where it is against the bricks.

I am sure you will find different opinions on this, as you have, but knowing what I know, this is my opinion.

Good luck and if you have further questions, just let me know.