Can I restore my discoloured shower tray?

QI noticed the shower tray in our Benimar and part of the surroundings were discoloured, a yellowish colour. I think this may have been caused by strong sunlight. Are there any cleaning products available or have you any ideas how to solve this?

ADiscolouration due to UV light is a common issue with many white plastics. Unlike domestic UPVC windows – which have UV stabilisation compounds – the plastics on many internal motorhome parts do discolour with age and time.

I suspect this is a problem that has got worse over time. It’s most common with ABS-type plastics, which are commonly used in shower trays and window/rooflight surrounds, and is thought to be a result of thermal surface degradation due to UV light.

There are two methods to get the colour back – the first is the best. Have an aftermarket liner product sprayed onto the shower tray. Firms such as Speedcoat speedcoateuro.com offer this service and, as well as various shades of white, there are many other colours (some people prefer a grey contrast colour).

This coating adds 1.5 to 2mm of thickness to the shower tray and, thanks to having tiny fibreglass strands in the paint, it also reinforces the tray, making it stronger. Many people have their shower tray repaired in this way after it has been cracked as it’s cheaper and faster than replacing an entire tray. The cost varies depending on the size of the shower, but it’s typically around £420.

The second method, which I’ve used successfully on discoloured nylon bike wheels, is to use hydrogen peroxide solution (yes, hair bleach). You need to use the creme developer volume 40 solution (which means it has 12% hydrogen peroxide) – a one-litre bottle costs under £10 on Amazon.

This chemical is unpleasant to use and you’ll need nitrile gloves, goggles and to wear old clothes or overalls and work in a well-ventilated area – open all the rooflights and windows. Protect any areas of the motorhome’s carpet from spillage and only open the bottle when you’re actually in the shower cubicle.

Mask off the drain surround – it must not come into contact with metal or anything else you don’t want to be bleached. It’s quite gel-like so you can apply it to all the white discoloured plastic surfaces and it will stay in place. Test it on a small area first and leave it for several hours. Then mop up the test patch with kitchen towel and rinse with water.

Once you’re happy with the patch you’ve tested, you can do the whole tray – generally the longer you leave it the whiter it will get. Mop up the gel with kitchen towels and try to flush as little solution as possible down the plug hole when rinsing it all off. Keep the water running to fill up your waste water tank and drain it down immediately.

The bleaching method works and you can repeat the process until you get the colour you’re happy with. Different areas of the plastic may react differently so streaking can be an issue. It’s not a permanent solution – it will discolour again in a few years so, if you can afford it, the coating method is the best solution.

Also, as a shower tray discolours, it loses some of its strength so will be weaker, which is why older trays are more likely to crack. This is another reason to go for a coating.