cracking between joints of margelles

[londoneye]

Hi

I wonder if anyone else has had this problem.

We have a waterair pool, installed now for three years.

This year when we opened the pool a few of the margelles were a little loose, but not of huge concern.

Over the last week, the joints between the margelles at the rounded ends of the pools have cracked open. We have lifted and re-set the margelles which were loose and we can see that the concrete ring beam on which the margelles sit is intact, so I do not believe it is a massive problem (ie I do not believe the pool itself is moving in the ground any more than you would expect it to).

Nonetheless we are of course slightly concerned. I am wondering if it could be because of the very hard winter followed by the very hot summer.

If anyone has had a similar experience or has any insights I would be grateful to hear of it!

[Théière]

Yes almost certainly because of the hard winter and slight ground movement. Personally I would not now build a pool using the ring beam construction as the ground under the ring beam moves and will always cause some displacement. This is of course with the benefit of hindsight. The only pool I would build now is polystyrene block and concrete as any pool that is not totally a self supporting structure can and will move. With winters being predicted to be getting harder for a few years it may become necessary to empty some as the weight of the ice is too much and could rupture some pools. I will no longer build any pool that cannot remain empty for some time.

Also the insulation properties of the polystyrene make it an obvious choice. 

[londoneye]

Thanks Theiere, so in your view (such as you can give it without having seen the thing) we shouldn't need to be overly-stressing about this ?

[Pierre ZFP]

[quote user="Théière"]

With winters being predicted to be getting harder for a few years it may become necessary to empty some as the weight of the ice is too much and could rupture some pools.

[/quote]

Just curious as I don't have a pool myself but did you really mean to say that? Surely the ice weighs exactly the same as the water it comes from?

Did you mean the expansion of the ice?  I'm not being picky but like I said, just curious.

[pachapapa]

[quote user="Pierre ZFP"][quote user="Théière"]

With winters being predicted to be getting harder for a few years it may become necessary to empty some as the weight of the ice is too much and could rupture some pools.

[/quote]

Just curious as I don't have a pool myself but did you really mean to say that? Surely the ice weighs exactly the same as the water it comes from?

Did you mean the expansion of the ice?  I'm not being picky but like I said, just curious.

[/quote]

I think the ice will have more dephlogiston in it making it heavier as a body but less dense as a medium.[:P]

[Pierre ZFP]

[:D][:D][:D]

[Théière]

Your'e right Pierre not one of my better postings, let me explain and expansion is what I meant.

Ice actually weighs less than the equivalent water, that's why it floats, the problem of ice on swimming pools if it get really cold is the ice forms a seal over the pool surface. If the weather remains cold the ice will thicken and become stronger as it thickens. If this continues the expansion of the ice will seriously stress the pool walls as it tries to expand by around 9% so a 10m x 5m will try to become 10.9m x 5.45 this will seriously rupture the pool walls so if the winter is that severe then emptying is the only answer and thin sheet wall pools etc will be crushed by the ground movement during the wet period over winter if empty. An ice slab of 100mm has 64x the loading and expansion of a 25mm sheet of ice

This is possibly going to happen as weather forecasters predict we are entering a very cold winter spell for several years.

 

 

[pachapapa]

Small point in natural science, often not appreciated. The freezing of a mass of stationary water is rather more complicated than the simpler concept of ice floating on water. Pure water has a maximum density at 3.98°C not 0°C as commonly believed. In simple terms this means that at the moment ice starts to form on the surface the warmer water at 3.98°C will be at the bottom of the pool and the less dense water at 0°C will be at thhe top of the pool.

This was all thought out by the supreme being when he/she created the world in order to prevent little fishes getting frozen solid at the bottom of their pools.

[Pierre ZFP]

Thank you both for taking the time and trouble to reply, I understand now.

I used to get in trouble at school for asking akward questions.  Like when we were taught that things get smaller as temperature drops, this little Munchkin would stick up his hand and say 'So why does ice float?'  Probably says more about the level of teaching than anything else

[pachapapa]

[quote user="Pierre ZFP"]

Thank you both for taking the time and trouble to reply, I understand now.

I used to get in trouble at school for asking akward questions.  Like when we were taught that things get smaller as temperature drops, this little Munchkin would stick up his hand and say 'So why does ice float?'  Probably says more about the level of teaching than anything else

[/quote]

[:D][:D]

My favourite question in arithmetic is ..... Why is a minus times a minus a plus?

As in -7 X -3 = + 21.[8-)]

[nomoss]

[quote user="pachapapa"]

My favourite question in arithmetic is ..... Why is a minus times a minus a plus?

As in -7 X -3 = + 21.[8-)]

[/quote]

If 7 people each put 3 apples on your table they are each minus 3 apples. If they then go away you are minus 7 people there, and you have 21 apples.

Simples [:)]

[pachapapa]

[quote user="nomoss"][quote user="pachapapa"]

My favourite question in arithmetic is ..... Why is a minus times a minus a plus?

As in -7 X -3 = + 21.[8-)]

[/quote]

If 7 people each put 3 apples on your table they are each minus 3 apples. If they then go away you are minus 7 people there, and you have 21 apples.

Simples [:)]

[/quote]

Smart rationale.[:)]

Sarko says 60 million will contribute to old age care during their lifetime then at 50 we'll make them take out additional private insurance.

Then I hope lots of them die.

I'll be rich. Hooray.[:)]

[londoneye]

Hi all

Me again !

We do not allow our pool to ice over in winter - if necessary we keep the filtration on constantly at times when it is likely to.

A further question, but related to original, please.

When we originally put the margelles on it was on a sand-cement bed and we are wondering if some kind of external flexible tile glue would work for re-setting them.

Could anyone recommend a product that is likely to be more effective than sand/cement please ?

[Théière]

Flexible tile adhesives contain a lot of polymers to add some flexibility so you could use that with the same flexible grout. or add the latex additive to the cement mix but cement is always hard so doesn't allow for movement. SBR additive gives a very strong bond. SBR additives are available in france to but you'll have to look around. If that dosen't work stick the margelles down with polymer sealant adhesive such as sika flex although expensive you could fill the grout gaps with the same. Other companies make similar products like stixall etc. 

[londoneye]

Theiere

Many thanks again - will look at all the options you have mentioned (or more accurately) 'he who does the repairs around here' will look at them.

ta