Seismic area, steep rocky outcrop - pool?

[darnsarf]

Our house stands on a rocky outcrop in the foothills of the pyrenees. It is pretty steep all around apart from one area of garden but this is kept flat due to a high (10metre) retaining wall, presumably stopping the soil from running down the natural slope of the hill.. A brief chat with the Architect said that this would require piles to be driven through the rock at least 11 metres to avoid it all crashing down. Sounds expensive! The only other option seems to be to build the pool elsewhere but 'outwards', supported at the outward end by piles and then presumaly filled in, with its own retaining wall.

The problem is made worse by the seismic movement in the area. I was told that this means that tiles are not practical and a liner will have to be used. But does this also impact the type of pool? Would a 'freeform' concrete structure work in such an area or would plastic pre-formed be the only option? Any comments from experts or folk who have been in a similar position would be much appreciated. Maybe no pool might be the best 'solution'?[:(]

[Poolguy]

Darnsarf

Yes It sounds tricky enough.

You know that anything is possible. Yes you can have a pool and you can choose

the shape you want. It’s a question of cost. As you know bridges are built in

areas of high geological activity and serve quite contentedly for many years.

What is needed before you get any planning or pool professional involved is a

structural engineer who is local enough to be familiar with the geology in your

area? Then once your 'site' has been assayed, then call in the Pool professional

and begin a design with the two disciplines.

The Architect may well be right, but it’s really not his job to specify that

sort of construction.

You could choose a concrete structure and leave it at that. I would tend to put

a liner in ot nevertheless as these are easier to repair and will not mind a

bit a wiggle and shake whereas a concrete/tile and resin pool will fail quite dramatically. You might also

consider a solution I have planned for another client in a similar situation

where we are installing a large above ground pool with decking surrounds. This

avoids all of the most expensive bits provided that there is some solid ground

to sit on.

Its projects like these that push the imagination further and out of which

great solutions are borne.

Contact me if you need more help.

Andrew

[Piprob]

We're in a similar area by the sounds of it - seismic zone, sloping in two directions, a field before we built on it. We chose a (blockit) pool constructed with hollow polystyrene 'lego' type blocks filled the re-inforcing rods and concrete.  The pool is 8 x 4 metres at a uniform 1.5 metres depth. It cost £15,000. There are quite a few others like it in our area and we hope we've made the right choice. The structure has been up for around18 months - but it's still standing!

[darnsarf]

Many thanks Poolguy and Piprob.

I think the Structural Engineer route is the sensible way forward. At least then we'll know whether we can build on the flat garden ground (without compromising the retaining wall) or 'sticking out' somewhere from the slope (it's about 45deg, so unlikely we'll be able to pin onto much!). A third idea (I know, it sounds a bit daft) is to have a longer pool/moat curving around the the front part of the house itself since this would enable the structure to hang onto some rock and mean that we could use the existing rock as a more 'natural' swimming area. We'll see...

I've read elsewhere on this forum about the lego bricks idea. It seems a great solution to getting a freeform shape. But apart from the standard rectangle ish shape and one or two 'bubbles' are there many truly freeform shapes out there. Certainly, from the airplane, they all seem conventionally shaped.

Thanks again for your advice

 

 

[Poolguy]

Darnsarf

Yu can certainly choose other systems which will give you the free form you

were asking about and a lot less work that the Styrene blocks and concrete. I

would be happy to give you some ideas on those types of systems.

From the outset I would say that these ideas are all academic until there is an

engineer to sign off on the project, as the whole lot might end up at the

bottom of your slope. Remember that 1 cubic meter of water is one tonne, and so

a 10 x 5 by 1.5-metre pool is 75 tonnes plus which is a lot of weight to

retain.

Also, don't forget that you also must include a security devise to your project,

Alarm, fence, cover or Abri. Hence if you take a free form 'Moat' for example

then a cover would be out of the question and an Abri would cost the earth. So

might be limited to a fence, or alarm.

Still, it does sound like you up for the challenge and so there is some really

gritty problems to tackle and occupy the mind.

PM me if you want further details.

Andrew