Decking is a popular outdoor living feature in many UK homes. It provides an attractive and functional outdoor space for relaxation and entertainment. However, the UK’s cool, damp climate can take its toll on traditional decking materials, leading to swelling, warping, splintering, and rotting over time. Consulting with experienced fencing contractors Aldershot can offer valuable advice on selecting and installing decking materials that are resilient to the challenges posed by the local climate, ensuring the longevity and beauty of your outdoor space.
Factors to Consider for Waterproof Decking
Climate Considerations
The UK receives over 30 inches of rain annually on average, with high humidity levels. This moisture can easily damage traditional wood decking over time.
Key trouble spots include areas that collect standing water, shaded zones receiving less sunlight to dry out the decking boards, and locations exposed to heavy winds driving rain onto the deck surface.
Snow, sleet, and freeze/thaw cycles in winter also test the durability of decking in the UK climate.
Waterproof decking is designed to withstand these conditions for enhanced longevity.
Material Types
There are several main options when choosing a decking material:
- Natural material that provides an attractive, traditional look
- Untreated woods like pine are prone to swelling, splintering, cupping, and rot when exposed to moisture over time
- Modified woods are available with special water-repellent treatments
- Ipe, massaranduba, and other tropical hardwoods have natural moisture resistance
- Made from mixture of wood fibers, plastics, and resins
- More water resistant than traditional wood decks, but may absorb some water between the decking boards over time
- Prone to moisture damage if poor drainage or improper installation
- Many composites feature protective polymer outer caps for extra protection
- Constructed from polyvinyl chloride plastic polymers
- Very waterproof and does not absorb or harbor moisture
- Can experience some expansion and contraction with temperature changes
- Limited color and pattern options compared to wood
- Made from fast-growing renewable grass
- The outer husk resists moisture; quality bamboo is as water-resistant as some hardwoods
- Proper treatment and sealing is vital for protection in wet environments
- No organic material means zero moisture absorption
- Lightweight, quick to install, and naturally waterproof
- Can be prone to dents and scratches over time
Installation Methods
Proper installation techniques are critical for long-term waterproof performance:
- Allow for adequate drainage and ventilation under the decking
- Use decking screws and hidden fastener systems – avoid nails that can back out and create moisture entry points
- Space decking boards properly to enable drainage and air circulation
- Seal all end grains and miters
- Consider slope for moisture runoff
Incorrect methods can lead to standing water that penetrates and damages the decking from below.
Popular Waterproof Decking Options
Now that we’ve covered the basics, let’s explore some specific decking materials that offer reliable waterproofing in the UK climate:
Composite Decking
Composite decking offers enhanced resistance compared to traditional wood. The plastic/resin components create a moisture barrier, while wood fibers provide strength and appearance.
Advantages
- Good water resistance – composites absorb less moisture than wood
- Attractive natural wood-like aesthetics
- Resists fungus and mold growth
- No splintering like wood decks
- Low maintenance requirements
Disadvantages
- Floating decking boards can still trap moisture underneath without proper drainage
- Some cheaper brands may warp or degrade faster than premium composites
- Limited color options compared to painted wood finishes
Among composite brands, Trex Transcend scores highly for water resistance. The deep wood-grain pattern hides moisture damage well, while the protective polymer shell prevents water intrusion into the decking boards.
PVC Decking
PVC stands for polyvinyl chloride. It utilizes polymers to create highly water-resistant decking boards without any wood content:
Advantages
- Extremely moisture resistant – water passes right through instead of absorbing
- Does not warp, rot, or splinter when exposed to standing water or excess moisture
- Available in colors that won’t fade over time
- Low maintenance
Disadvantages
- Can show visible expansion or contraction with temperature changes
- Heat absorption can be problematic in warmer climates
- Hollow profile sounds “tinny” when walked on
Azek Vintage PVC Collection is a top choice in wet environments. Featuring natural wood colors and textures, vintage barnwood and weathered finishes disguise PVC’s plastic roots for an attractive, waterproof decking option.
Modified Wood Decking
Special wood modification techniques (acetylation, thermal treatment, etc.) create lumbers with enhanced moisture resistance:
- Acetylated wood undergoes a reaction with acetic anhydride that prevents water absorption in the wood cells themselves. This process utilizes Accsys’ proprietary technology to create durable, stable decking woods.
- Thermally-modified wood is heated to very high temperatures using a special process that permanently alters the wood’s physical properties. Known as thermowood, this material is more water-repellent than traditional species. Brands like Lunawood utilize thermal modification to produce attractive, sustainable decking suitable for the UK climate.
Advantages
- Offers the attractive, natural look of real wood decking
- Retains the feel and texture of wood without a “plastic” appearance
- More environmentally sustainable than composite or PVC
- Naturally resistant to rot, decay, and insect damage
Disadvantages
- Upfront cost tends to be more expensive than traditional wood decking
- Can experience slight expansion and contraction over time
- Needs to be sealed properly during installation for optimal moisture protection
Properly maintained modified wood offers a superb balance of waterproofness and aesthetics for eco-conscious homeowners in the UK.
Maintenance and Longevity
Whichever decking you choose, implementing proper maintenance practices is vital for waterproof performance and longevity:
Routine Maintenance
- Clean deck regularly with soap/water and a stiff bristle broom
- Pay special attention to mildew-prone areas that don’t dry out quickly
- Wash off spills like wine or grease immediately
- Check for splinters, popped nails, or warped/cupped boards annually
- Reseal decking every 1-2 years, especially end grains
- Ensure proper drainage and ventilation underneath to prevent moisture buildup
Longevity Factors
With routine cleaning and sealing, quality waterproof decking can last 20-30 years in the UK’s wet climate.
Exact lifespan depends on:
- Brand and materials (composites vs. wood vs. PVC)
- Sunlight and moisture exposure levels
- Overall installation workmanship
- Regular maintenance habits
Budget decks may need replacing after 10-15 years. Premium materials with proper upkeep can last longer.
Frequently Asked Questions
What makes a decking material waterproof?
The outer shell resists moisture penetration into the underlying structure. Materials like plastic composites and PVC prevent water intrusion and passage. Meanwhile, dense tropical hardwoods or modified woods feature water-repellent properties in their cellular structure.
The key is blocking external moisture from being absorbed into the decking itself using protective barriers or modified materials.
How does climate affect decking in the UK?
The UK’s cool maritime climate brings ample precipitation and humidity. Traditional woods readily absorb this moisture, eventually resulting in swelling, rotting, mold growth, and loosening of nails over consecutive seasons.
Waterproof decking is designed to withstand these wet conditions for enhanced durability and lifespan.
Are all composite decking materials waterproof?
Not necessarily. While composites resist moisture better than pure wood, cheaper formulations still absorb some water over time. This leads to swelling, staining, and degradation.
Look for composites featuring protective polymer caps such as Trex Transcend. The top layer blocks external moisture while inner wood fibers provide strength. High-performance cores stay dry and stable.
Can waterproof decking withstand heavy rainfall?
Quality waterproof brands can tolerate temporary standing water from heavy rainfall. Premium composites and PVC allow the water to drain away without retention or passage into the decking boards. Meanwhile, dense tropical hardwoods also repel occasional pooling.
The key is ensuring proper drainage and ventilation underneath. While waterproof decking can handle moisture on the surface, trapping it underneath speeds deterioration.
What maintenance is required for waterproof decking?
While low-maintenance compared to wood, some periodic upkeep is still required:
- Wash periodically with soap and water using a stiff broom to dislodge grime
- Resealing boards every 1-2 years to protect against UV and moisture damage
- Checking for mechanical issues like popped nails or improper spacing
- Ensuring unobstructed drainage pathways underneath
This routine care enhances longevity while retaining the appearance and water integrity of the decking.
Is PVC decking better than composite for waterproofing?
PVC decking offers maximum waterproofing thanks to its completely polymer composition. Water cannot penetrate the solid PVC core or protective cap layer on deck boards. Plus, PVC doesn’t support mold growth when surface moisture pools temporarily.
However, some composites like Trex Transcend rival premium PVC decking in moisture resistance. They cost less while providing a more attractive, natural wood aesthetic.
So PVC blocks moisture intrusion completely, but well-engineered composites can achieve similar waterproofing for less cost.
Can modified wood decking resist UK weather conditions?
Yes, with proper installation and maintenance. Brands like Lunawood and Accoya utilize special production methods to permanently alter the moisture-absorbing properties of natural wood at the cellular level.
The resulting decking boards resist swelling and rotting when exposed to typical UK weather patterns. Although denser and more water-repellent than traditional pine or cedar, sealing and upkeep are still required for optimal performance.
How to install waterproof decking for optimal performance?
Correct installation is crucial to complement the waterproofing properties of the decking boards themselves:
- Allow for adequate drainage and airflow underneath to prevent moisture trapping
- Use recommended board spacing for drainage and ventilation
- Fasten boards with hidden decking screws versus nails to reduce points for water intrusion
- Always seal endgrains after cutting using wax or sealant
- Ensure proper slope and consider strategically placed drainage gaps for improved runoff
Thanks for reading our post, feel free to check out our other services:
