Gunnite Rolled Edge Cracks and Cool Deck Cracks...help!

[Poolscout]

I have some cracks in the rolled Gunnite and in the Cooldeck...

I have started to do an epoxy repair on the Gunnite...still need to drizzle in more and sand to FLUSH with sides, get rid of SLOP.

Q1 - What do you all think...there are more in the Gunnite I have not touched and some hair line ones too small to fill!

Q2 - What about the Cooldeck???

[web]http://picasaweb.google.com/kevinliliya/POOLCracks[/web]

Kevin

PS - Pool was built in 2003

 

[saraiks]

Concrete/Gunnite cracks are generally attributable to two factors..

1. Improper curing
2. Inadequate surface prep/shifiting of underlying soil

Fortunately repairing cracks is easy as long as there are no underlying soil issues. A variety of products are available depending upon location of crack, cure time etc.. Take a picture of the crack with you to a Home Depot /Lowes nearby and find someone knowledgable there to find the right kind of "filler".

From the pictures you posted it looks like most of of the cracks are hairline and there is no major settling of soil involved. So if you go with an easy flowing color matched epoxy fill you should be able to achieve a fairly pleasing result.

Kool Deck repair patches are also available and here is a good repair video

http://www.poolcenter.com/e-zpatch2.wmv


my 2 cents..

 

[Poolscout]

I will be getting the EZ Patch 2 as soon as I locate it!

Thanks very much.

 

[dolemite77]

how do you know if your situation is underlying soil? I am getting the same cracks in our cool deck also...

 

[TresW]

Concrete/Gunnite cracks are generally attributable to two factors..

1. Improper curing
2. Inadequate surface prep/shifiting of underlying soil

There's a much larger factor when it comes to flatwork/ decking- lack of control & expansion joints. It's hard to tell in those photos because they are closeups, but if control and expansion joints were not installed (or were installed at too great a spacing) then that is why you've got cracks in the deck. A lot of people don't realize this, but it is perfectly normal for concrete to form hairline cracks. Control joints are not there to prevent cracking, they are there to give the concrete a clean joint to crack along so that you don't see the cracks. Typically you want to have control joints every 5' o.c. and expansion joints no more than 20' o.c. Control joints can be sawcut in if they weren't installed originally (although this may be challenging to do if there is an existing coating on the concrete without damaging the coating).

Now the gunite cracks are really a head-scratcher because of the way they are occuring (parallel to the edge of the pool). Do you know if a bond beam was installed along the perimeter, and if so if it is the full width of the radiused coping? The only thing I can think of there is that the edge detail is not fully supported and there is some differential movement taking place.

 

[TresW]

how do you know if your situation is underlying soil? I am getting the same cracks in our cool deck also...

Usually this shows up as heaving or settling. I'm sure you've seen sidewalks and/ or driveways before where one section was higher than the other at an expansion joint; that's an example of soils movement (and also of improper joint detailing). Some geographical areas are worse than others. Expansive clay soils are the worst.

Tiny hairline cracks over time are usually the result of thermal expansion/ contraction, especially if there are inadequate control joints (see above post). Buckled paving where the sides are no longer flush or where there is a heave at the crack is indicative of soils problems and/ or inadequate subgrade preparation. These problems can show up particularly after severe rain events.

 

[Poolscout]

Do you have an example of a "Bond Beam", is there anyway for me to check?

I would tend to agree that the outside edge appears to be somewhat unsupported. I am not savvy enough to know what I am looking at though.

Thanks...I am wondering if I should excavate the rolled edge and fill it with something more supportive?

 

[JasonLion]

A bond beam is a thicker section of concrete at the top of the pool wall that helps stiffen the wall and supports the coping.

It looks to me like they rounded the top of the wall, spread the plaster/pebble over it, and then continued on beyond the edge of the concrete. If the plaster continues beyond the underlying concrete it won't be strong enough to hold it's self up and will crack along the edge. You have cracks in other places as well, so that can't account for all the cracks, only the ones that run along the outer rim of the pool.

 

[Poolscout]

I think that sums it up...I have unsupported plaster! grrrr....

 

[TresW]

It looks to me like they rounded the top of the wall, spread the plaster/pebble over it, and then continued on beyond the edge of the concrete. If the plaster continues beyond the underlying concrete it won't be strong enough to hold it's self up and will crack along the edge. You have cracks in other places as well, so that can't account for all the cracks, only the ones that run along the outer rim of the pool.

Yeah, now that you describe it that way that's exactly what it looks like. That explains why the pebble/ plaster seems to curve down the other side and terminate into dirt instead of concrete. That definitely would explain the lateral cracking!