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Simple questions deserve simple answers. Find out everything you need to know about timber and composite decking here. Contact FMT Solutions for expert advice on your deck project.
Decking ServicesIf you’ve ever searched for decking advice online, you’ll know how quickly it turns into a rabbit hole of conflicting answers. Joist spacing, concrete bases, slippery boards, composite movement. Everyone has an opinion, but not all advice is created equal.
This FAQ-style guide cuts through the noise. Below, we answer the most common decking questions clearly and practically, based on real-world installation experience, not guesswork.
In most cases, decking joists should be spaced 400mm apart for timber decking and 300mm apart for composite decking. Composite boards are less forgiving than wood and require closer support to prevent sagging or bounce.
Joist spacing may also vary depending on board thickness, direction of installation, and whether the deck will support heavy furniture or high foot traffic. Getting this wrong is one of the most common causes of deck failure. Take a look at our decking installation guide for more information.
Decking spindles (or balusters) should typically be spaced so that no gap exceeds 100mm, in line with UK building safety guidance. This spacing helps prevent accidents, particularly where children are present.
Beyond safety, consistent spindle spacing is crucial for a clean, professional finish. Uneven gaps are very noticeable once the handrail is installed and difficult to correct after the fact.
Yes, composite decking does expand and contract, particularly with temperature changes. This is completely normal, but it must be accounted for during installation. Learn more about composite decking in our explainer.
Manufacturers specify minimum expansion gaps at board ends and edges. If these gaps aren’t allowed, boards can press against each other, lift, or become noisy over time. Correct spacing is essential for long-term performance.
Composite decking can be slippery when wet if the wrong boards are chosen or fitted poorly. Higher-quality boards usually have textured, anti-slip surfaces that perform well even in damp conditions.
Drainage also matters. Boards must be installed with the correct spacing and orientation so water can run off quickly. Shaded or enclosed areas benefit most from professional layout planning.
Yes, decking can be laid on concrete, but never directly. If you've read our guide to DIY building a decking, you'll know a properly constructed subframe is essential to allow for drainage, airflow, and levelling.
Fixing decking straight onto concrete traps moisture and leads to long-term problems. When done properly, concrete bases can actually provide a very stable foundation, especially for patios being upgraded to decking. This is when it's often easier to get your decking professionally installed.
You can jet wash decking, but it needs to be done carefully. Excessive pressure can damage timber fibres and strip protective treatments, while composite boards can be marked or discoloured.
Using the correct pressure setting, keeping distance from the surface, and working with the grain all help reduce damage. For many properties, a controlled clean is safer than aggressive pressure washing. Read this guide to find out how to clean and maintain your deck.
Timber decking typically lasts 10–15 years with proper maintenance, while composite decking can last 20–30 years when installed correctly.
Lifespan depends heavily on preparation, drainage, and ongoing care. Many decks fail early not because of the materials, but because of poor groundwork or incorrect spacing during installation.
Neither option is “better” in every situation. Timber decking offers a natural look and lower upfront cost but requires regular maintenance. Composite decking costs more initially but is lower maintenance and longer lasting.
The right choice depends on budget, appearance, usage, and how much upkeep you’re willing to commit to. An on-site assessment usually makes this decision much clearer.
A bouncy deck is usually caused by incorrect joist spacing, insufficient support, or a weak subframe. This is especially common with DIY builds and composite decking installations.
Over time, bounce can lead to loose fixings and board movement. Fixing it properly often involves structural changes beneath the deck, not just surface adjustments.
In many cases, decking doesn’t require planning permission if it’s under a certain height and not located in restricted areas. However, rules vary depending on property type and location.
It’s always worth checking before starting work, especially for raised decks or commercial installations where regulations are stricter.
Green algae usually forms due to moisture, shade, and poor airflow. Preventing it starts with correct spacing, drainage, and regular cleaning.
Timber decking also benefits from periodic treatment to protect against moisture and staining. Proper installation makes maintenance far easier and reduces how often deep cleaning is needed. You can contact a professional for decking maintenance, or find out how to clean your decking yourself.
Decking may look straightforward, but most long-term issues come down to preparation, spacing, and structural decisions made at the start.
Professional decking installation ensures:
FMT Solutions have installed and maintained bespoke decking for residential and commercial customers for decades. Get a no-obligation quote for your decking installation today.
Decking questions usually come from one place: people wanting to get it right the first time. The details matter — and small mistakes can become expensive ones later.
If you’re planning a decking project and want clear answers tailored to your space, getting professional advice early can save time, stress, and costly repairs.