I’m John. I’ve been building decks for over 20 years, and for the last 10 years I’ve specialised in composite decking.
Over that time, I’ve noticed more and more negative reviews about composite decking. It got me thinking: is the criticism justified, and is composite decking actually the problem?
The answer isn’t quite that simple.
There are definitely people who have had bad experiences with composite decking, and understandably, those people are going to have a negative opinion of it.
But is the problem the composite itself?
Or was it the product they bought?
Or was it the way it was installed?
From a professional’s point of view, I’m going to explain why I think there are so many mixed opinions about composite decking.
Not All Composite Decking Is the Same
The first thing to understand is that not all composite decking is made to the same standard.
So judging all composite decking based on one bad experience isn’t really fair.
You may have bought a low-quality product and simply expected more from it than it was designed to deliver.
Or you may have bought a good product but had it installed by someone who didn’t properly understand how composite decking needs to be installed.
And sometimes, you can even buy an expensive, premium product from a reputable manufacturer and still have a poor experience because it was badly installed by someone who was supposedly an approved installer.
There are so many different scenarios.
Why Some People Love Composite Decking
There are also plenty of people who absolutely love their composite decking.
And why wouldn’t they?
If they’ve had no problems with it, they’re unlikely to go online and leave a negative review.
Maybe they bought a quality product, had it installed properly by an experienced deck builder and have had exactly the experience they expected.
But what did they do differently?
Did they research the product?
Did they read reviews?
Did they check the warranty?
Did they buy from a reputable supplier with a proven track record?
Or did they buy whatever was on special offer at B&Q because they’d seen a Facebook advert with hundreds of glowing reviews and an amazing discount?
There’s a reason some products are much cheaper than others.
You Usually Get What You Pay For
If something is dramatically cheaper than the alternatives, there’s usually a reason.
Take a Rolex.
A genuine Rolex isn’t cheap, but people buy one because they expect a premium product and are prepared to pay for it.
On the other hand, if you’re on holiday in Thailand and someone offers you a “Rolex” on the beach for £20, you probably aren’t going to complain too much if it stops working six months later.
It might look similar from a distance, but that’s about where the similarities end.
You really do get what you pay for.
The same principle applies to composite decking.
But there’s another important factor: expectations.
Some people’s expectations simply aren’t realistic. They’ll buy the cheapest product available and expect it to perform like a premium product.
When it doesn’t, they’re understandably unhappy.
The problem is that the product may actually be performing exactly as expected for what it is.
So expectations need to be realistic — not just when choosing the decking boards, but also when it comes to the installation.
The Installation Matters More Than Most People Realise
Let’s say you’ve got an old, tired timber deck.
You’ve had enough of staining it every year and decide you want something lower maintenance.
You buy some composite decking, spend the weekend ripping up the old boards and screw the new ones down.
Job done, right?
Not necessarily.
One of the biggest mistakes people make is assuming that their existing timber deck frame is suitable for composite decking.
It might not be.
Composite boards often require much closer joist spacing than traditional timber decking.
For example, some hollow composite boards need support at around 300–400mm centres to prevent excessive movement and sagging.
I’ve seen old timber decks with joists spaced at 400mm, 600mm and, in some cases, even 800mm apart.
Put composite boards onto a frame like that and you could end up with boards that flex like a trampoline — or, in the worst case, crack or fail.
So before you start, check whether your existing frame is suitable for the product you’ve chosen.
The manufacturer should have installation guidelines available. Read them.
If the existing frame isn’t suitable, rebuild it correctly.
And if you are rebuilding the frame, follow the manufacturer’s installation instructions.
This isn’t a guessing game.
You might say, “Oh, that’ll do.”
But the guidelines are there for a reason.
It isn’t rocket science, but it does need to be done properly.
The Manufacturer’s Guidelines Exist for a Reason
Whether the product is cheap or expensive, there will be installation guidelines.
They’re there to make sure the product performs as it was designed to.
If you feel confident enough to install your own composite deck, that’s absolutely fine.
Just make sure you:
- Check the installation guidelines.
- Use the correct materials.
- Build the frame to the required specifications.
- Use the correct fixings.
- Follow the manufacturer’s instructions.
It sounds obvious, but getting these things wrong can completely change how the finished deck performs.
When Composite Decking Starts Going Wrong
Let’s say you’ve had a composite deck installed by someone who told you they knew what they were doing.
A few months later, the boards have faded badly or scratched easily.
That could be down to the quality of the boards.
There are low-quality boards available with printed patterns on an uncapped surface. These are available in both hollow and solid versions, although they’re often hollow.
But what if the problem isn’t the boards?
What if:
- The edging boards are falling off.
- Huge gaps are appearing between the boards.
- The boards are bouncing when you walk across them.
- The deck feels unstable.
- The frame wasn’t built correctly.
In those cases, the problem could have nothing to do with composite decking itself.
It could simply be poor installation.
I’ve Seen This Many Times
Over the last 10 years, I’ve had hundreds of enquiries from people who are disappointed with decks they’ve had built.
I’ve viewed some of these as paid consultations because, unfortunately, my time is valuable.
And quite a few of these people originally asked me to quote for their deck in the first place.
They then took my design to another company who said they could do it cheaper.
When I ask why they went with someone else, the answer is usually very simple:
“They were cheaper.”
And that’s where some of these problems begin.
“My Friend Can Do It Cheaper”
One common example is:
“A friend said he could do it cheaper for cash. He’s a carpenter and does loads of flooring and timber decking.”
Being a carpenter doesn’t automatically make someone a composite decking specialist.
Composite decking has its own installation requirements, and those requirements need to be understood and followed.
The Big Deck Example
Another situation I see quite often is with large decks being built as part of an extension.
For example, a customer might be planning a £100,000 extension.
They want a large deck because the new extension is going to be around four feet above the garden. They want steps, balustrades and a large decking area.
They ask me to price everything so they know roughly what the project will cost.
Let’s say they choose a premium product such as Trex, with glass balustrading, on a timber frame.
For a 50m² deck, I might quote around £30,000.
So they budget £100,000 for the extension and £30,000 for the deck, then remortgage for around £150,000 to give themselves some breathing room.
Everything seems covered.
They book me in for six months’ time.
Then, five months later, I get the phone call.
The extension is six weeks behind schedule and has gone £30,000 over budget.
They can’t afford the deck anymore.
They ask if I can do it cheaper or postpone the job.
I explain that I can’t build the same deck for less.
I could use a cheaper decking product, but that’s not what they originally wanted.
So they speak to their builder.
The builder says:
“We can do it for £15,000. We’re already here finishing the extension.”
Sounds great.
Fast forward 12 months.
I get another phone call.
“John, can you help?”
The deck has huge gaps.
It’s bouncy.
The edging has fallen off.
The colour doesn’t look anything like the samples.
So I explain that I’m happy to come and inspect it as a paid consultation and see if I can advise them.
On several occasions, homeowners have ended up taking the original builder to court to try to recover the cost of removing the badly built deck and starting again.
And unfortunately, this isn’t unusual.
Here’s a Real Example
I was contacted by a homeowner who had employed a local landscaping company to carry out a complete garden makeover on a new-build house.
Their total budget was around £20,000.
The landscaper had quoted around £5,000 for a 30m² composite deck.
That’s roughly £160 per square metre.
For comparison, my composite decking projects start at around £400 per square metre.
That’s a huge difference.
And at £160 per square metre, you’re certainly not going to be getting premium materials because, in some cases, the premium materials alone can cost around that much.
The homeowner asked me to come and take a look.
As you can see from the photographs, it wasn’t what anyone would expect from a professionally installed deck.
When I arrived, the young landscaper was clearing away his tools because he’d been asked to stop work.
He told me he could reduce some of the labour costs from his invoice and that I could reuse the materials he’d already bought.
I told him I couldn’t do that because the materials weren’t suitable for the application.
The timber wasn’t UC4 treated.
The fixings were internal wood screws.
The decking boards weren’t worth what the homeowner had paid for them.
But one of the biggest problems was the frame.
The joist spacing was all over the place.
Some were around 450mm apart, while others were closer to 700mm.
They weren’t consistently spaced at all.
I explained that this was one of the main reasons the deck couldn’t be used as it was.
His response was:
“It’s tip-top, mate. I’ve built loads of decks like this.”
So I said:
“Google it, then. Look up the manufacturer’s installation guidelines for the joist spacing.”
He did.
And almost immediately he apologised and admitted he hadn’t realised.
So what would you call that?
Was it laziness?
Was it overconfidence?
Or simply not knowing what he was doing?
Whatever the reason, the result was the same.
And this landscaper had apparently built lots of composite decks like this.
So how many homeowners have ended up with badly built decks because the installer simply didn’t know the correct installation requirements?
Those homeowners are then understandably going to have a very negative opinion of composite decking.
But that’s installer error, not necessarily product failure.
What About “Approved Installers”?
This is another area where homeowners need to be careful.
Some manufacturers have approved installer schemes.
These can include professional decking specialists, carpenters, landscapers and builders.
The problem is that these tradespeople can have very different skill sets.
In some cases, approved installers have attended a relatively short training course covering the basic installation of that manufacturer’s products.
That’s useful, but it doesn’t necessarily make someone a decking specialist.
Knowing how to fix a board down doesn’t automatically mean you know how to:
- Build the correct subframe.
- Design and build stairs.
- Install balustrades.
- Deal with complicated levels.
- Build a large raised deck.
- Correctly detail drainage.
- Solve difficult site conditions.
So don’t automatically assume that someone who says they’re an “approved installer” is a fully trained decking specialist.
A few hours in a classroom doesn’t replace years of experience.
What Happened During COVID?
During lockdown, there was a huge increase in demand for garden projects.
People were working from home.
Garden offices became incredibly popular.
And people wanted decking and outdoor spaces.
At the same time, more installers joined manufacturer-approved schemes.
Unfortunately, this also meant that some less experienced companies started taking on composite decking projects.
The result was a lot of rushed and poorly constructed decks.
Some of those decks are now failing years earlier than they should.
And that has undoubtedly contributed to the negative reputation composite decking sometimes gets.
Things Are Improving
To be fair, some manufacturers have recognised the problem and are taking steps to improve their installer schemes.
Companies such as Trex and Millboard have tightened their requirements and removed a number of installers from their schemes.
There are now stronger requirements around things such as:
- Site inspections.
- Photographic evidence of the installation process.
- Proof of the correct timber treatment.
- Correct external fixings.
- Following the manufacturer’s installation requirements.
- Checking the quality of completed work.
That’s a positive thing.
They’re trying to give homeowners a better chance of finding a competent installer.
Of course, these installers can cost more than the average landscaper or general builder.
But you’re paying for something that is often overlooked:
peace of mind.
So, Is Composite Decking Actually the Problem?
There are plenty of reasons why composite decking attracts negative reviews.
But many of those problems are avoidable.
Before you decide that composite decking is rubbish because you’ve read a few bad reviews, ask yourself some questions.
Did the homeowner buy the right product?
Did they research it properly?
Did they understand what they were buying?
Did they check the warranty?
Did they buy from a reputable supplier?
Was the product installed correctly?
Was the frame built to the manufacturer’s specifications?
Did the installer use the correct materials and fixings?
Was the installer actually experienced in composite decking?
Or did the homeowner simply choose the cheapest quote?
And most importantly:
At what point was the actual composite decking to blame?
Because there is a massive difference between a product failing and a product being incorrectly installed.
I’ve seen plenty of badly built composite decks.
I’ve also seen plenty of fantastic composite decks that still look great years later.
So, in my opinion, composite decking isn’t automatically good or bad.
The product, the installation and the expectations all matter.
Do your research.
Buy the right product for your budget.
Use an experienced installer.
And most importantly, make sure the person installing it actually knows what they’re doing.
Because when composite decking goes wrong, it’s very easy to blame the boards.
Sometimes, though, the boards were never the problem.