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Fibreglass Monocoque InGround Swimming Pools in the UK or France

What is a Fiberglass Swimming Pool?

First of all lets get the spelling right - it is like this

Fibreglass Swimming Pool

It's just not Fiberglass!

How are fibreglass Swimming Pools made?

They are made in one piece in a factory before being taken to site on a very large lorry and craned into the hole that has been dug for it.

The factory shop floor will have a number of male moulds set down on the floor so that the pool is made upside down.

The fiber glass swimming pool manufacturing process

The process is as follows:-

1. The male mould is cleaned up
2. One or several layers of gel coat are sprayed onto the male mold and allowed to cure (Dry). This becomes the hard surface of the pool that you walk on.
3. The main waterproofing layer is sprayed onto the male mold over the gel coats - this is what stops the water from attacking the fibreglass structure. The fibreglass structure is very vulnerable to moisture and so if this layer fails the structure will deteriorate. Some manufacturers do not even bother with the waterproofing layer but just rely on the gel coat.
4. The fibreglass matting is then applied and covered with resin. Reinforcing strips of light timber like balsa wood or lightweight plastic strips are often used to stiffen the pool sides and connect up the lifting points etc.
5. The whole pool is allowed to cure for the requisite period.
6. The finished pool is lifted off the mould and the process starts again.

The Poor Reputation of Fibreglass Pools

Fibreglass is not only spelt wrongly most of the time - remember it is not FIBERGLASS - think of it the other way round first of all - i.e. glass fibres - and you will never get it wrong again!

The main problems with Fibreglass pools arise from lack of expertise and poor quality control. There are manufacturers that make an excellent product and many more that do not.

They can look like this - click on image for a bigger picture!

Or like this:-

You have been warned!

In the top picture the pool was of very poor quality and only lasted for a couple of years.

In the lower picture the fibreglass pool is of superior quality but it has "popped" out of the ground simply because the hose being used to fill the pool got knocked and fed all the water down into the fill that surrounds it.

In these circs that pool acts just like a yacht and floats!

Fibreglass Roman Steps

Some readers are probably wondering about fibreglass roman steps that are for sale in every French pool shop and that are often used by artisan pool builders that use concrete blocks to build their pools. It is probable that quality control on the production of fibreglass steps is even less stringent than for whole swimming pools.

Moreover the steps are highly loaded by the water inside the pool at the junction between the steps and the walls - and this is where the ends of the fibreglass strands are normally exposed and subject to moisture that travels along the strands deep into the structure of the steps. The pool structure is also weakest at this point.

When the fibreglass gets wet it just deteriorates into a soggy mess. The only thing that protects the fibreglass is the very hard gel coat that eventually suffers from microscopic cracking. As soon as this happens the water gets into the vulnerable fibreglass backing and deterioration is then quite rapid. This happens very frequently with fibreglass boats where it is mistakenly known as "osmosis".

I expect that everyone with a fibreglass pool or roman end will be very unhappy with their pool in 5 to 10 years time. All fibreglass is susceptible but it is true that very high standards of manufacture under strictly controlled conditions following Lloyds Register of Shipping Specifications for Marine Applications will allow both pools and roman steps to last much longer - but I wonder how many French fibreglass manufacturers do this?

Fibreglass Pools - Summary

Cost - Low to medium

Advantages

Speed of installation

Disadvantages

Highly prone to manufacturing defects because the pool should be made in a factory with controlled humidity and temperature. Defects will not be immediately apparent because they manifest themselves through osmosis where the water in the fibre-glass moves to the surface causing osmotic blisters within a few years. In 5 years the pool could look terrible and you will not get much help if you claim on your pool installer - he will be long gone. Many cheap fibre-glass yachts suffer from the same defect and it is all caused by lack of temperature and humidity control in the factory.
Prone to damage during transport and installation because of the size of the unit - may need a very large crane or even a helicopter to get them into the required location.
Most have an attractive maximum life of 10 years and surface deterioration can occur in less than 10 years - very high quality units with strict quality control may provide a much longer guarantee - so look out for these!
Can "POP" out of ground if the ground water at your property reaches the ground surface and the pool water is held at mid-point of the skimmers where it should be. In this instance the net flotation force is at least 150 kg per square metre of pool or about 11 tonnes - much more than the weight of the fibre-glass shell
Are highly unsuitable for swelling clay soils that can just push the sides of the pool in.
The sizes quoted are misleading because the suppliers quote the external area of the whole unit - the actual swimming area is about 20% less in an 8 x 4 pool
Often sold by fly by night firms - make sure that your supplier has been in business for at least 5 years at his current business address. Normally they pack up business and move on when the level of complaints and the local grapevine reduces their sales!
Choice of colour is very limited and colours are dull and lifeless. Friezes cannot be provided around the top of the pool and it is the frieze that really makes a pool look good.
Often provided with inadequate filtration systems providing a full water change in 24 hours and not the 6 to 8 hours that is required to guarantee water quality.

I can hear some of you thinking - this is all bullshit - I have never heard of such problems with fibreglass pools.

The Australian Fibre-glass Experience

If you are thinking in this way just type "fibreglass pool repairs Australia" into Google.

Evidently such pools have been popular in Australia for a lot longer than in Europe and now there are dozens of firms that do nothing but repair fibreglass pools. When these repairs are made the old gel coat is taken off and the fibreglass structure is repaired and then the whole pool is coated with an epoxy resin. Epoxy resins are a lot more expensive than polyester resin and this often causes the repair costs to be higher than the original pool cost.

One last point about fibreglass pools - if you read the small print on the contract it will probably say that "The pool should never be emptied and if you must do so then get the pool installer to do it"

This is because more and more fibreglass pools are "POPPING" out of the ground. Just bear in mind that every pools will need to be emptied a few times in its life for all kinds of different reasons. Having one that you cannot empty is preposterous!

In the 1990's UFI Pools Limited made about 450 fibreglass pools in NEW South Wales, Australia, that have all had to be repaired by the NSW because of Australian law. The laws in France do not operate on this basis.

FibreGlass Pool websites

The following websites demonstrate what some of the issues are.

http://fibrecoatfibreglaze.com.au/content/view/21/30/

This is an Australian website – they have 40 years experience of these pools over there.

Just note what it says on this page that is advertising refurbishment of fibreglass pools.

“Many old fibreglass moulded pools have osmosis problems, cracks, or out of shape floors”

Here is another one;

http://nhml.com/resources/2006/5/1/hydrolysis-of-fiberglass

This is an American laboratory

It says on this site

“Hardly a week goes by without our being asked to do a failure analysis of something made of fiberglass. The failure may be an industrial tank, piping, a yacht hull, a swimming pool, or a water tank in an RV.”

Here is another one;

http://www.grpsuppliers.com/dorset/Troubleshooting.htm

This a fibreglass company based in Dorset in the UK and is a Question and Answer page

“Visible Signs of Poor Quality in GRP Project:
My mould seems to be 'blistered'. Why is this?
This would suggest that there is signs of delamination within the mould. Larger blisters could be due to the resin being under cured. Blistering is sometimes un-noticable until some months after moulding.
Cracking has appeared on my mould. Why is this?
This could be because the gel coat is too thick. Gel coat should never be more than 0.6mm thick.
A "crazing" pattern has appeared. Why is this?
This can occur immediately after moulding or can indeed appear some months later. It will show as fine lines and is commonly caused by using unsuitable gelcoat or resin. Also be careful when spraying as the addition of extra styrene in gelcoat can be a common cause.
I can see the fibre pattern. Why is this?
This could be because the gelcoat has been applied too thinly or because the reinforcement has been applied before the gelcoat has hardened properly. It could also mean that the moulding has been pulled from the mould before it is ready.
The gelcoat doesn't seem to be adhering properly. Why is this?
Sometimes, when you notice a blister in your mould, this could mean that the gelcoat has not adhered as it should. The most common reason for this being that the gel coat has been left too long to cure. Poor consolidation of the laminate is also a problem.
Wrinkling? Why is this?
This is caused when the solvent attacks the laminating resin because the gel coat has under cured. ensure the following:
The resin and catalyst have been mixed properly
The gel coat is not too thin
Mouldings are kept away from direct moving air sources (point hot air blowers away from your moulding)
Control the temperature in the workshop
There is a 'spotted' effected on my mould. Why?
This is caused when the resin formulation has not been inadequately dispersed”

What a catalogue of problems!

And what about this site where they probably produce a superb product;

http://www.sapools.co.za/premoulded.html

Just look at the detailed specification of what they call “Pre-cast fibreglass pools” – if you are going to buy a fibreglass pool in France or the UK you should find something of equivalent specification. But note that even with high quality pools like these no warrantee are not provided.

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