Cantilever Deck - large gap between tiles and deck

[DesertJon74]

First off, thanks for all the great advice I've been reading here.

I have a cantilever concrete deck, ie the decking extends out over the pool about 3 inches. There are no coping stones.

My problem is this: there is an irregular gap between the deck and the tile stones below it. The tiles are some sort of mica-like stone in what must be mortar.

The gap between the stone tiles and the deck is approx 1/4 to 1/2 inch around the entire pool. I realize it is a good thing they are not attached so as to avoid cracking the tiles. However, this gap is the home to many spiders, crickets, ants etc etc. I also suspect that during rains moisture may be running beneath the decking into the pool.

I can't imagine there is supposed to be an open gap like this. The pool is probably about 8-9 years old. Can a gap like this be filled with a flexible caullk or mastic of some sort?

 

[PoolGuyNJ]

Please post a pic. The reason the space is there is so the deck and bond beam can expand and contract without impacting each other. Typically, there is something to act as a separator between the two and a flexible plastic trim edge to keep things looking neat.

Scott

 

[DesertJon74]

Ok, I posted some photos on photobucket:

http://s1190.photobucket.com/albums/z458/desertjon74/

What I noticed is that it looks like the original builder did mortar all the way up from the tile to the bottom of the deck. It does appear that the mortar is still intact in some places and worn away in others.

 

[waste]

Welcome to TFP!!

I'd certainly give a good listen to what Scott is saying!

For myself, I'd imagine that some expandable, waterproof caulk could be used - you certainly DO NOT want water getting back in there!

I'd like to hear Scott's take on this before I give advice on applying the caulk

 

[DesertJon74]

The proverbial guy at the pool store told me I could use some silicone sealant (caulk?) at Home Depot.

Not being an expert on what is the best type of non-toxic sealant to use in a pool please give me your opinions.

As far as water getting back in there, there has probably been a little bit here and there from splashing. What will eventually happen from the moisture?

Again, thanks for any input.

 

[PoolGuyNJ]

Gently remove and loose/weakened mortar. Fill the space with clear silicone. I personally like GE, not DAP. Make sure it gets packed some between the bottom of the decking and the bond beam top, sealing the edge. Inspect annually.

Scott

 

[DesertJon74]

Thanks - I will do that. It will probably take a great many tubes, as the gap between the tiles and deck looks like it extends back a few inches. I might wait until next spring/summer when the water isn't 50 degrees. Any harm in waiting that long -- I don't anticipate water will be able to get behind the tile without swimmers in the pool.

 

[G-MAN]

Use some type of a backer to fill the crack before caulking; Home Depot sells backerod for this purpose. It will need to be trimmed to fit tightly. The caulk does not have to be deep. In fact, some caulks will not cure properly if too deep - follow the caulk directions and push your backerod in as necessary. Make sure everything is dry before caulking. I would recommend taping off your tile and deck edge if possible. Use Sika-flex or Vulcum gun-grade (no sag) sealant. The Sika is available at most Home Depots. Both are available in gray. You could even blow handfuls of sand onto the wet caulk to make it look more like the original cement.

 

[bk406]

G-man beat me to it, but yea, backer rod would be what you want for this.

 

[Guest]

It looks to me like you have a single pour cantilever deck; is this correct? If so, do you have panels of the deck that are heaving (moving)?

Pools and decks expand and contract at different rates. The coping should always be poured first, and expansion joint placed and then the deck poured after. This allows for the differential movement and the two entities can do their own thing without impacting each other.

 

[DesertJon74]

It is cantilever with each pour about 4 feet wide or so, separated from each other with a felt liner.

I did some research on these types of decks and found out exactly what you're saying: that the expansion could potentially crack the tile/pebbletec.

What's interesting on my pool is that the original builder appeared to have mortared all the way up the side of the pool from the tile to the bottom of the deck. Most of this is now missing but it is still intact in spots. (I tend to run low calcium in this pool -- possible that the material was leached away from long-term low calcium? I've only been in the house < 1year) There is no expansion joint that I can see unless the 'mortar' I'm seeing is a cleverly hidden flexible material with a mortare-like surface.

What's disturbing to me is that maybe they just didn't put in an expansion joint. There was a well-known builder around here, California Pools I think?, that was found to have chintzed on jobs, not installing working main drains, etc. Apparently the owner ended up comitting suicide last year. This is all second-hand.

 

[DesertJon74]

Fyi, I heard this rumor from a Leslie's guy last summer. Based on the general opinion on this board, prob full of ****.

 

[PoolGuyNJ]

Typically in my area with solid practices in place, a felt type membrane is placed on the top of the bond beam just before the pour to allow separate expansion and contraction and a molding or silicon based grout like Boss 803 to keep things neat.

Alas, some cut this corner as a cost cutting.

Scott

 

[Guest]

In defense of the local California Pools (and no, I do not work there!), they have always been a stand up company, which is somewhat dictated as corporate culture, as I understand. I have not heard of any suicide stories either, although I don't hear everything so it could be true!

I will give one quick California Pools story as an example of what I know of them: I went and saw a 10+ year old pool that needed to be re-plastered. One of the benches in the deep end had some gunite delamination and I needed to rebuild it prior to plaster, which is an extra expense. The homeowner (who was the original owner of the pool) mentioned that California Pools had built the pool and had offered him a lifetime structural warranty. He called California Pools and told them what was needed and California Pools called me and authorized the work to be billed to them. I don't really consider a step or bench to be structural, but California Pools stepped up without question!

 

[DesertJon74]

Chuckle - thanks simicrintz. Yes it appears CA pools still in operation around here.

The topic came up with the Leslie's guy because I inquired what the ~8 inch diameter UFO-shaped disc with the floating centerpiece was for -- apparently to shunt water from the main drain in the event the water level dropped into the skimmer.

He said don't bother keeping it in place. I do have an auto-fill but I'm sure my pump would self-destruct if that ever malfunctioned.

Poolguy, there definitely is not an expansion joint in place. I guess I should consider myself lucky I see no evidence of buckling or cracking. I plan on filling that joint with silicone as soon as the water temperature rises next spring. Do you see any harm in waiting as long as water will not get behind the wall?

 

[PoolGuyNJ]

I assume the pool is just sitting idle in standby with the cold weather and will remain that way till Spring. As such, I see no harm in waiting.

Scott

 

[DesertJon74]

Is there any reason DAP Concrete and Mortar Filler and Sealant would not work in this situation?

According to the label it is flexible, paintable, water cleanup, waterproof.

I have some one-step Deck-O-Seal but I found it to be so thick I could not get it out of the gun. Even if I could, it seems extremely messy, difficult to clean up, and has a nasty odor to boot.

I need your expert opinions on this. Thank you.