Capped vs Uncapped Composite Decking: Fading, Staining and Mould

Capped Vs uncapped composite decking
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Composite decking is in this year, and for good reason. Composite decking is strong, low-maintenance and eco-friendly. It usually comes in more expensive than traditional wooden decking but the much higher lifespan offsets the cost over the years.

Find out more about the general benefits of composite decking or see this article for a comparison of wooden and composite decking

There is a large and growing variety of composite decking available, with many styles and types available. So how do you know which decking to go for from the crowd?

This article covers one of the main differences you have probably noticed in your searching; capped vs uncapped decking with recommendations depending on your needs. If you are thinking of looking at other surfaces entirely there are some great alternatives to decking which can save you money.

What is composite decking?

Banner saying what is composite decking with some examples of grey and brown decking

Composite decking is a blend of plastics and wood. The plastic film can include polypropylene or polyethylene, which work well with wood fibres to create a tough material that’s more stable than 100% plastic decks.

This product is heated, formed into board shaped lengths and then cooled. The resulting boards need far less maintenance than traditional wood decking whilst looking more authentic than plastic alternatives.

Composite decking is made in a similar manor to PVC decking but the two products are very different. See this detailed breakdown of the differences between composite and PVC decking.

What do capped and uncapped mean?

There are two main types of composite boards: capped and uncapped. Uncapped decks are cheaper but have a shorter lifespan due to the wooden fibres being exposed. Uncapped decking has less protection against fading, staining and mould.

Capped composite boards have a cover that is bonded to the core during manufacturing process which provides greater protection against these issues in addition of looking more realistic than uncapping decks when fully assembled on site.

Uncapped decking also has less resistance to wear and tear as it can be more easily scratched or gouged than capped board.

What are the benefits of capped composite decking? 

Capped composite decking with its protective outer layer typically offers a much longer lifespan and greater durability than uncapped composite decking.

The length of a guarantee is a good sign of how confident a manufacturer is in the product. Some capped composite decking brands offer a 30 year guarantee with many offering at least 20 years against weather and general wear.

When it comes to uncapped decking the longest guarantee you are likely to find is 10 years, still a long time but no where close to the expected lifespan of capped decking.

Cost of capped vs uncapped decking

As you would expect the cost of capped decking is considerably higher than that of uncapped composite decking. You can expect to pay around £40 per square meter for uncapped decking and £80 per square meter for capped decking boards.

So it it worth the extra cost? Maybe. There are a few things to think about when making the decision.

Firstly, the decking boards are only part of what makes up the whole decking. If you are getting it professionally installed the labour will make up a large chunk of the cost.

With the labour and base materials included you will likely be looking at a minimum of £120 per square meter for uncapped decking or £160 for capped composite decking.

Secondly, there is the base to think about. Good treated wood will likely last for as long as the decking its self with signs of age only starting to show after 15 years or so. However if your decking is built with poor quality wood then the base may need replacing after only 10 years.

There is also a third consideration that not many people think about: resale value For those who plan on selling their house at some point down-the line , the choice of decking could have a significant impact on how much money they are able to get.

The lower quality composite options will be worth between 15% and 25 per cent less to prospective buyers who can see it as a liability. Using high end decking will likely please any potential buyers and add to the value of the home.

So if you’re looking to sell your house for top dollar in a few years, then it’s worth investing more money upfront and installing high quality composite decking that will never need replacing .

Ease of maintenance

When it comes to maintenance uncapped decking will be slightly more difficult to maintain as the years go by. This is due to its more porous nature which will is slightly more prone to algae and mould growth.

This is a very fine point and one which should not overly concern you as both capped and uncapped decking will be very resistant to algae and mould.


Another area where capped composite decking stands out is in appearance. Uncapped composite decking seems to currently be limited to a few set styles. They are nice and most people are happy with them but moving to capped decking offers a much larger variety.

From aged wood effects to deep greys and realistic browns, capped composite decking offers a much more personalised choice of colours and styles.

Overall you can really just tell the difference when you look at one and the other. For most people uncapped will be just fine but for those looking for a more refined look capped decking may offer more.

Design options

Composite decking with glass balustrade picture framing and decking lights

Depending on the style of decking you are looking for you may find yourself limited to capped decking. This is because uncapped decking is generally hollow and weaker than its counterpart.

This weaker structure has some downsides


Some types of handrail and balustrade are built into the frame however many types simply screw through the surface of the decking and into the joists below. The weight and force applied when installing these is too much for hollow decking.

Picture framing

The picture frame border design is extremely popular for decking but is very difficult to build successfully in uncapped decking. This is because the available clips don’t hold normal planks in place when perpendicular to the central boards.

Holding them in place requires screws which will damage the boards if even a little too much force is applied. If you would like a picture framed design in hollow decking you can achieve a similar (but not quite as good) look with corner pieces.

Composite seating and planters

Composite seating and planters built with two types of soil grey decking boards

We get a lot of requests for decking with built in seating and planters. These features can look great and you can get really creative with them however if you opt for uncapped decking they can be very difficult to build.

This is for the same reason as with the picture framing. Its likely that you will need to attach the decking planks at odd angles where the clips will not be sufficient to hold it in place.

It is possible to use hollow decking for seating and raised planters but it is also difficult and should only be attempted if you have used the material before and know how work around its structural weaknesses.

for these reasons we only offer enhanced designs in capped solid composite decking.


Installation is generally a little easier with capped composite decking due to its wider acceptance of screws and other fixings. Capped decking boards respond much more like wood than their hollow counterparts.

See our guide on how to install composite decking

Raised decking

Raised decking can be made from either type with no real difference initially. All decking is elevated from the ground and supported by joists so no matter what type of raised decking you want it will work the same.

The one consideration is safety in extreme conditions or over long periods of time. Composite boards are hard to break but the weaker uncapped boards are more prone to this.

To avoid any heavy falls going through the decking or a long drop when the boards eventually deteriorate it is recommended that you consider capped raised decking.

This becomes an essential if you are installing balustrade which crews onto the surface of the decking as discussed above.


Trucks illustrating the transportation of composite decking which can take longer with capped decking

The final point when opting between these two types should be which one you’ll have easier access too. With its lower price tag and more limited options, uncapped decking is usually more readily available and has quicker delivery times of as little as a couple of days.

On the other hand, capped composite decking is typically less available, especially for less popular styles. We have found many styles have up to a month lead time on them which can be too much for those wanting to get started on their project quickly.

Capped decks are on the rise, but more home owners will still opt to purchase an uncapped product for a variety of reasons including better availability and shorter delivery times as well lower prices

Which type is better overall?

To conclude there is no right answer to this question. Of course capped composite decking does offer considerable advantages however these advantages are only realised over long periods of time (15+ years) or where more complex designs are needed.

The guarantees offered are against wear and tear and UV fade however the decking is likely to be usable long after these time spans have passed. So if you are looking for a simple design at ground level or close to that hollow composite decking will likely serve you well with the extra spend on high end decking not really adding that much value.

However if you are looking for a decking system that is going to last over the next 25 years then you will certainly want capped composite. The guarantees offered by this product against wear and tear, UV fade as well being waterproof make it perfect in high traffic areas around patios or decks where people may be cooking.

If you would like your decking professionally designed and installed then we offer a bespoke design service with a range of decking options.

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