Considering Replacing Damaged Deck with Cantilever Deck

[NJ-Bob]

I have a damaged 17 year-old concrete pool deck for a vinyl-lined pool. (Pic 1)


The area by the pool steps, which is a molded one-piece set of steps, is sinking (Pics 2, 3, 4) and there is a long crack running through several sections to the side of the pool. (Pic 5)





The steps also appear to have sunken an inch at the exit point (at the top of the steps; Pics 6, 7). Also, the coping by the steps has sunk and is experiencing misalignment. Hard to see in the photos.



Once contractor proposes a cantilever deck. They have told me they have done many cantilever pool decks but they are not a pool builder. The estimator didn’t think the steps were sinking when she visited during the pool season and water was lower. With the water higher, it looks obvious.

I asked how the cantilever deck is kept from shifting the pool wall with expansion and got this reply: “We use a bond-breaker material between the pool shell and the concrete to allow for proper movement as the concrete expands and contracts with temperature changes.” Case closed?

This made me wonder about the liner track. The coping seems to be directly on top of the track. (Pic 8) Not all tracks are like this apparently. Will bond-breaker material affect keeping the liner track in place? I'm also wondering if the track will get out of position when the coping is removed.


The proposals doesn't mention addressing why the area is sinking. Is it safe to assume it will stop? We bought the place in 2013 and it seems like the area has sunk more since then. Could water be seeping in at top of steps from spashing/waves and eroding the ground underneath?

Any advice appreciated.

 

[ajw22]

Your ground is moving.

You have a slope from the house down past the pool on your property. Nature is taking its course.

You have a retaining wall between the house and the deck. The retaining wall is trying to hold back the slope, which is putting pressure on it. That pressure transfers to the concrete deck.

You should have had a flexible expansion joint at the bottom of the wall so that the wall would not put pressure on the concrete slab. The cracks on the deck are due to the pressure from the retaining wall.

That continues as the ground drops by your steps since you have no retaining wall below the pool to stop the ground from moving down the slope.

There is no simple fix, as the liner pool was built on an unstable slope. A gunite pool would have been more stable in the ground.

To stabilize the slope, you need a retaining wall and a lot of concrete below the pool, and I am not sure your property lines will allow that.

That is a long explanation for why your deck is cracking and the steps are sinking. It will not stop unless the slope is stabilized.

If you replace the deck an expansion joint should be installed between the retaining wall and the deck.

The devil is in the details, such as whether the bond breaker material is properly installed and the deck is not coupled to the pool wall.

I prefer a paver or brick deck with traditional coping so that expansion joints can be at the retaining wall and around the pool coping. This will allow the deck to move and be adjusted as the ground moves over the years. You will be chasing problems around the pool every few years as nature makes adjustments.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

 

[Bperry]

I have a damaged 17 year-old concrete pool deck for a vinyl-lined pool. (Pic 1)
View attachment 641797

The area by the pool steps, which is a molded one-piece set of steps, is sinking (Pics 2, 3, 4) and there is a long crack running through several sections to the side of the pool. (Pic 5)
View attachment 641796
View attachment 641798
View attachment 641799
View attachment 641800

The steps also appear to have sunken an inch at the exit point (at the top of the steps; Pics 6, 7). Also, the coping by the steps has sunk and is experiencing misalignment. Hard to see in the photos.
View attachment 641801
View attachment 641802

Once contractor proposes a cantilever deck. They have told me they have done many cantilever pool decks but they are not a pool builder. The estimator didn’t think the steps were sinking when she visited during the pool season and water was lower. With the water higher, it looks obvious.

I asked how the cantilever deck is kept from shifting the pool wall with expansion and got this reply: “We use a bond-breaker material between the pool shell and the concrete to allow for proper movement as the concrete expands and contracts with temperature changes.” Case closed?

This made me wonder about the liner track. The coping seems to be directly on top of the track. (Pic 8) Not all tracks are like this apparently. Will bond-breaker material affect keeping the liner track in place? I'm also wondering if the track will get out of position when the coping is removed.
View attachment 641803

The proposals doesn't mention addressing why the area is sinking. Is it safe to assume it will stop? We bought the place in 2013 and it seems like the area has sunk more since then. Could water be seeping in at top of steps from spashing/waves and eroding the ground underneath?

Any advice appreciated.

Gonna agree with above. But I can also suggest that there may water leaking into the soil and helping that soil move even more. I don’t think a cantilever style deck is going to change anything. It’s actually a little harder to deal with decking problems when the deck is over the edge of the pool.

 

[ajw22]

But I can also suggest that there may water leaking into the soil and helping that soil move even more.

Irrigation of the grass along that are keep the soil flexible and adds to the ground movement. It doesn't take any leaks.

 

[Bperry]

Irrigation of the grass along that are keep the soil flexible and adds to the ground movement. It doesn't take any leaks.

The water level at the top of the steps and a liner section that looks dislodged from the track makes me suspect leaking. I could be wrong but figured I’d highlight it.