Will Witt 19th July 2006
I was a bit shocked at the weekend when I realised how long it has been since we added any posts to this blog and so I will be making a special effort to keep it more up to date. As promised I will bring you up to date with the pools that we have built recently at the weekend.
During a long drive back to the office from the site of a pool that we are building near Mirande in Department 65 I was reflecting on the lessons that we have learnt from recent projects and thought it might be useful to share these.
Water, water everywhere!
The most striking issue is that of the last 6 pools that we have built - we have found large volumes of water during the excavation for 3 of the pools. This always causes a major problem because:
- The water makes the ground supporting the pool unstable
- It is impossible to complete the pool unless the water level can be reduced
- The likelihood of catastrophic failure if the pool ever needs to be emptied
Why is the water there? - it may be leaking drains or the effluent from a sewage filter bed fed by the fosse septique or water from the roof drainage. These are all easy to deal with because the flow can be diverted or blocked off. But what if the water is there because of a high ground water table. There may be millions of gallons in the hill above your property that makes it impossible to drain your pool excavation.
In all the three pools mentioned above the water was caused by a high ground water table. This highlights why a site investigation is so necessary - but even a site investigation may not discover that there is water problem because the ground water table level will vary from summer to winter and can even rise half a metre after an intense summer storm.
How do we get over this problem?
The solution always depends on the sub-soil conditions at the site.
If the sub-soil is gravel it may be impossible to build the pool below the ground water level - particularly in late winter or early spring when ground water levels are at their highest. The only solution is to lift the pool level and provided it with decking and-or landscaping to integrate the pool into its surroundings.
If the subsoil is solid clay it is unlikely that ground water is feeding into the pool excavation and so a drain needs to be installed beneath the pools lowest level and the water pumped out.
In really difficult circumstances (this applied to all of the 3 pools mentioned above) - the ground may be a mixture of clay, gravel and or rock with seepage occuring at various levels. In these circumstance each pool needs a bespoke solution that may involve numerous wells with pumps and large volumes of reinforced concrete to stabilise the foundations of the swimming pool - this is what we did in each case.
What are the implications for pool purchasers?
The most obvious implication is that it is very difficult to install a kit pool in these circumstances - if you have bought a kit and hit water during installation fill the hole up to about half a metre above water level with concrete and build the kit pool walls up from that level.
What do you do if you think you have water logged ground in your garden
You could consult an expert but because there is a bewildering variety of kits for both above ground and inground pool installations on the pool installation market as well as the traditional installers that build reinforced concrete filled concrete block and rendered pools with liners, reinforced concrete filled polystyrene block pools with liners (As we install) and tiled reinforced concrete pools it will be difficult to get objective advice. I recommend that:
- If economy is your main consideration - buy and install an above ground kit pool
- If you must have an inground pool get a traditional installer to provide a liner pool because below ground pool kits are not suitable for waterlogged ground - and tiled pools leak! - see elsewhere in this blog.
What other problems have we come across recently?
We keep meeting clients (or are told about friends of clients) who have had problems because their pool installer has run into financial difficulty.
The reason for this happening is that pool installation is a very competitive and risky business and this results in numerous bankrupties of quite large French companies. There are many installers that cut their margins to get work and this results in the following:
- Poor or non-existant after sales service
- Non-completion of pools after the builder has received most of the money
- Failure to replace faulty parts
What can you do about it?
What you cannot do is to refuse to pay the pool builder any money until he has finished the pool. None of us could operate on that basis because the cost of the materials and labour involved is so high that we would effectively be operating as bankers as well as pool builders
What you can do is
Ask your pool builder for:
- References from 3 recent clients of the pool installer - pick one and telephone him
- A balance sheet from the previous years trading
- A sight of the company bank statement that is less than 3 months old
These three simple checks may reveal issues that you are not comfortable with - if your pool installer cannot provide a satisfactory explanation then go elsewhere!
What else have we discovered recently?
We install the best quality pump and filtration equipment (manufactured by Hayward) that is designed to provide a complete pool water change in 6 to 8 hours. Even with this equipment we still find that pool water quality can sometimes be a problem. We can only imagine what the water quality is like in pools that only provide a water change every 20 hours or so. We have also found that many other manufacturers pumps fail quite quickly and that their fiberglass filters can split and leak.
Pool Alarms
We are all waiting to see if the law is going to change so that pool alarms are outlawed. We find it quite odd that many people install an alarm at an unoccupied property and assume that they are complying with the law. The alarm is only lawful if there is someone within earshot of the pool that can respond to the siren.
In our experience pool alarms are very unreliable - but the makers require the alarm to be returned to them if faults arise - but how can you be complying with the law if the alarm is being repaired elsewhere.
Pool safety fences mat not be attractive - but they do work and with a bit of careful design they can be largely hidden behind shrubs etc.
Regards
Will Witt
Bluepools SARL