Replacing the wood between concrete around pool

[Dirk]

+1 on trim-a-slab. Easy to install and looks sharp on driveway expansion joints. I think they sell through Lowe’s now - though you can buy direct from them if you live in Houston area.

I just watched the video. This could be an excellent way to go for the OP. Super easy installation. And I see now why the stuff wouldn't get pushed down into the joint by stepping on it. Looks like it would hold up better than the Sika, too. The only caution: this stuff looks to be more appropriate for a control joint, which doesn't expand and contract. If put in a true expansion joint, that has a lot of movement, I wonder how well it will do... I'm going to get some to fix my sidewalk!

 

[Backyard_Lap_Pool]

I just watched the video. This could be an excellent way to go for the OP. Super easy installation. And I see now why the stuff wouldn't get pushed down into the joint by stepping on it. Looks like it would hold up better than the Sika, too. The only caution: this stuff looks to be more appropriate for a control joint, which doesn't expand and contract. If put in a true expansion joint, that has a lot of movement, I wonder how well it will do... I'm going to get some to fix my sidewalk!

Should be fine for expansion. Much more movement capable than a 1x4 for sure. The real beauty of trim-a-slab is that they pieces can be pulled out and reset as needed. The excavation crew ripped several of mine out of the driveway when scraping off the compacted soil. I simply pulled the pieces out of the dirt pile and re-installed them after power washing driveway. Neighbors have silka-flex joints on their driveway and our trim-a-slab looks much better after 5 years.

 

[JimMarshall]

I just watched the video. This could be an excellent way to go for the OP. Super easy installation. And I see now why the stuff wouldn't get pushed down into the joint by stepping on it. Looks like it would hold up better than the Sika, too. The only caution: this stuff looks to be more appropriate for a control joint, which doesn't expand and contract. If put in a true expansion joint, that has a lot of movement, I wonder how well it will do... I'm going to get some to fix my sidewalk!

These appear to be more flexible than typical asphalt expansion joint material that is used.

 

[kooldecker]

I didnt want to chime in about sand as a sub base lol. But as far as sand to fill the expansion joints . That comes right from the back of the sikaflex tubes. Ive caulked miles of wearhouse floors and pools and everything in between. My opinion people that dont know concrete talk alot about expansion and contraction joints and all sorts of things. Anybody that rwally knows concrete knows one thing about it. Its going to crack where it feels like it . You can do all the protective measures you want. Bigdog i never thought to ask this but what state do you live in? (Makes a difference)

 

[Dirk]

I didnt want to chime in about sand as a sub base lol. But as far as sand to fill the expansion joints . That comes right from the back of the sikaflex tubes. Ive caulked miles of wearhouse floors and pools and everything in between. My opinion people that dont know concrete talk alot about expansion and contraction joints and all sorts of things. Anybody that rwally knows concrete knows one thing about it. Its going to crack where it feels like it . You can do all the protective measures you want. Bigdog i never thought to ask this but what state do you live in? (Makes a difference)

Can you please show us where Sika is recommending sand as a filler in a concrete expansion joint? Thanks!

This is directly from a PDF from Sika (https://usa.sika.com/dms/getdocumen...93a1f9/PDS-Sikaflex-SelfLevelingSealant.pdf):

Recommended application temperatures: 40 to 100 °F (4to 38 °C). Condition sealant to 65 to 75 °F (18 to 38 °C)
before using. Cut plastic tip to desired size and puncture
airtight seal at base of tip. NOT FOR SLOPED SURFACES.
Maximum sealant depth is 1/2 in. (12.7 mm) and width is
1–1/2 in. (38.1 mm). Minimum depth is 1/4 in. (6.3 mm)
and width is 1/4 in. (6.3 mm). Pour sealant into joint slot
in one direction and allow sealant to flow and level out
as necessary. Tool as required, although minimum tooling
is necessary. Proper joint design is 2:1 width to depth
ratio. Always use bond breaker tape or closed cell backer
rod for support on horizontal joints.

 

[pooldv]

Foam backer is the right thing to use under the sealer. Putting sand in the joint would impact the ability of the joint to expand and contract which is the whole point of the joint.

 

[Bigdog43]

Previously, I wasn't talking about my expansion joint (where the pool decking meets the concrete), I was really talking about the space between each concrete slab around the pool. I tried the slab gasket and at first I thought it was going to be good, but just like one poster above mentions, it can get pushed down below the concrete line. I have a few weeks off of work now and I'm going to try to do it right. I need to replace the slab gasket between the concrete slabs as well as the expansion joints. I'm thinking I will do the foam backing and self leveling caulk method. he gaps between the concrete slabs (1 inch in most places) are much bigger than the gaps between the pool decking and the concrete (.25-.5 inch).

 

[Bigdog43]

 

[Dave31410]

...The following is conjecture, but something I'm going to be trying. If you're dealing with expansion joints, they move around. And can move a lot. They'll be larger at night (the surrounding material got colder, and contracted), and they'll be smallest at the end of the hottest part of the day. They'll be larger in the winter than in the summer. The amount of the difference could be as much as 1/4". Maybe more.

There is no way that the average pool deck will expand that much. The expansion coefficient for concrete is 5.5 millionths per degree F. So for example a 10'wide deck with a temperature change of 100 degrees would expand 10'x12"/ft x100degrees x .0000055 = 0.066"

 

[PoolguyinCT]

There is no way that the average pool deck will expand that much. The expansion coefficient for concrete is 5.5 millionths per degree F. So for example a 10'wide deck with a temperature change of 100 degrees would expand 10'x12"/ft x100degrees x .0000055 = 0.066"

Well said Dave, the decking would be a jig saw puzzle with the OP reported numbers.

If OP is seeing his reported metric, the slab is floating not expanding.

 

[Dave31410]

... Is sand not used under slabs? How bad is it, that it was done at my house?

Well pretty much the entire state of Florida has houses with slabs over a compacted sand base.