Repairing Coping Pavers Edge Seal

Stuart Batt

New member
Feb 28, 2021
The pool I look after is fibreglass IG and has concrete pavers built around it. The pavers are a limestone cream light yellow finish.

It was installed in 1998.

Bullnose Coping Pavers:
They were originally laid on a bed of limestone coloured mortar at the front bullnose edge and under the rear edge. The same mortar was placed between the underside of the pavers and the top edge of the fibreglass pool and is about 20mm thick. The mortar has cracked and fallen out in some places around the pool. This is allowing the sand under the pavers to be washed and blown into the pool. It is easy to see this happening as I can see a residue mark of the local fine black sand on the fibreglass under the coping tiles and well above the pool high water line.

95% of the coping pavers are still fixed down well at the front and back however they often have part of the mortar seal to the fibreglass missing. There are a few pavers that have come loose front and back and I will have to relay them with new mortar. However in the majority of cases I just need to replace the old cracked mortar seal.

The non coping pavers are simply laid on a bed of yellow sand.

Any ideas on the best way to do this and the best materials to use at the moment the options I have are:

Use the original mortar mix.
Sikaflex Pool
Selleys Landscape Construction adhesive
Expanding Foam
Tile over the gap.

The object is too:
Stop the sand
Neaten up the seal line
Reinforce the front of the coping pavers if needed ie stop them from moving downward if someone steps on the edge next to the water.
Refix the few Coping pavers that have come loose at the front bullnose and rear edges.

Your ideas appreciated:

Stuart Batt


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Stuart, show us pics of the problem area so we can understand your situation better.

Stuart Batt

New member
Feb 28, 2021
Hi everyone,
This photo shows the problem.
If you look underneath the front edge of the bullnose coping pavers (CP) you can just see a mortar joint between the underside of the CP and the top of the FG pool. In many places around the pool this has cracked or fallen out. The dirty marks you can see are due to the fine black sand we have here in Perth being washed out from under the CP and into the pool when it rains or when the reticulation is on.

The problem is the amount of sand getting washed into the pool which also has organic humus with it which creates a large ongoing pool maintenance problem

Other things I have found out:
It appears the cream mortar used under the back of the CPs is the same stuff that you can see from the front.
Remember this pool is over 20 years old.
The edge beam on the pool is 250mm wide.
Coping was installed with no concrete bond beam around the pool.
Each coping paver has basically a bed of cream mortar at the back of the paver which is continued across the edge beam.
There is no separate adhesive used between each CP and the fibreglass.
I believe this might be the way pools were normally done in WA 20 years ago.
There are no expansion gaps between each coping paver. They are wedged in together so tight that they are near impossible to lift up.
CPs are limestone look concrete.
The CPs butt up to the rest of the patio paving which are the exact same material and are simply laid on yellow paving sand.
Apparently this is a common problem in WA.

Solution Ideas I have:
1. Just replace the old mortar with the same premixed cream mortar swan cement provide premixed 20kG bags. I am researching additives that will make this more flexible.
2. Mapei Keropoxy Epoxy Grout coloured to sandstone rated for full immersion pool service.
3. Mapei Mapesil T Silastic Caulk coloured to sandstone rated for full immersion pool service.

I am leaning towards solution 3 as the interface between the CP and the Fibreglass (FG) is a moving joint. Intend to use a closed cell builders backing rod behind the Silastic.
And wirebrush the FG to get better adhesion.

Gap is only 15mm
Large temperature variations in WA we regularly hit 42degC (110degF) in summer. In winter we regularly get down to 5degC (approx 40degF) at night and rarely down to 2degC.

Excuse the mess around the pool area however I am in the middle of a number of repairs to the pool and drainage around the house caused by a very large Fig Tree (20 feet across and high) recently removed.

See Photos
Top is close up of problem
Bottom is overview of pool.

I have just commissioned a new DAVEY 25" sand filter, non return valve and repaired a number of underground pipe leaks.
The pool backwash soakwell is way too small as well it barely allows for a 2 minute BW and then rinse before it overflows. You can see the sand pile over near the shed, that is where the soakwell is and it will be replaced with a much larger one.



photo.JPGphoto (1).JPG


Well-known member
Mar 30, 2007
Virginia Beach
I cannot find any information on Mapesil T Silastic Caulk but it sounds like silicone caulk? If so that is what I would use. I used pool grade silicone caulk to install a tile line in my fiberglass pool as well as to bond the pool to the underside of my flagstone deck. It has held up great over the years.