Weather hazards like rain, thunderstorms, and lightning can be devastating. Yet a serious cause of worry for most deck owners is standing water.
This is because as time passes, the pool of water can degrade your deck and negatively impact the soil beneath it. To mitigate this risk, it’s essential to invest in high-quality drainage solutions from Outdoor Direct to maintain the integrity of your outdoor spaces.
However, capped composite deck boards won’t be affected by standing water like traditional wood would be. Because composites are water-resistant materials, you won’t have to worry about the decay, mildew, or mould that might occur with timber wood.
This is different for wooden decks, as they can become a breeding ground for mildew, fungus and flies without adequate drainage.
This is why knowing how to drain water from your deck is important.
Composite Decking and Water
The vast majority of second-generation composite decking boards are water-resistant. This is because they are manufactured with a combination of low-density polyethylene (known for their low moisture absorption properties) and a structural material like wood. Polyethylene effectively protects the deck board from moisture damage by repelling water from the deck.
Furthermore, nearly every composite decking available in the market is capped. By adding a polymer cap, the water resistance property of the deck is enhanced. This is why capped composite decking can withstand moisture and is impervious to inclement weather elements like rain. Its decking core is impenetrable for the rain to pass through due to its protective shell, ensuring minimal upkeep.
Despite these features, composite decking is not waterproof. Many composite deck boards have low water absorption rates even when exposed to water for too long. However, they can easily repel water due to the gap between their boards and their plastic component.
This is why composite boards are perfect for swimming pools, hot tubs, plunge baths and other damp areas.
Why is there standing water on my composite decking?
A possible cause of standing water on your composite deck is incorrect installation or failure to follow the installation guide properly. Other reasons for standing water include:
- Inadequate ventilation and no gaps for drainage: There must be at least a 5mm or 10mm ventilation gap.
- Wrong fixing centres.
- Based on your decking brand, centres ought to be around 600mm and 450mm or even less.
Another reason may be that the joist on the framework might have been titled a little, leading to standing water at that particular point.
Ways to Drain Water from your deck
Moisture Barrier Below A Deck
What’s the right way to build a rain barrier underneath your deck?
We will explore more details below.
However, note that when installing a new deck, your priority should be safeguarding your substructure. Thus, installing flashing will prevent water from getting to the perimeter of your house and the supporting joists of your deck.
A good method to create a rain barrier underneath your deck is by hammering flanges into your decking board gaps. This way, moisture is prevented from seeping into the deck boards, and if the installation is done properly, it can function as a mini-gutter to drain water.
Flexible Sheeting
Some homeowners prefer installing corrugated plastic sheets or flexible sheet systems underneath their existing decks to collect rain.
However, avoid using any under-joist structure that lets water flow through your joist and beam onto a gutter. Here are some disadvantages of under-joist drainage systems:
It causes the joist to get wet as rain drops through the deck gap and into the drainage system underneath. The water gets to the pan and flows out but soaks the joist first.
An under-joist drainage system can collect moisture. Regardless of whether your decking is composite or deck, if you have installed a ceiling underneath it, there won’t be air to dry the wood properly.
In the heat of summer, as the temperature becomes hotter, the wet wood will quickly decay. This might cause rot due to a lack of ventilation and the presence of moisture and heat.
Under-Deck Drainage System
Constructing a drainage system under the deck during installation is a more effective method to drain water and maintain your deck. This entails placing the under-deck drainage system above the joist to prevent water from touching the structure that supports your deck.
An over-joist system has a membrane that collects water that flows through the deck board. The pooled water is drained away from the structure through a gutter that flows out at the deck’s edge. This gives a measure of protection to the deck beams and joists from dampness and improves the durability of screws and fasteners.
A waterproof system can help ensure your deck has a drier space underneath it for storing a number of outdoor items. It can also present opportunities for outdoor lounging, entertainment and relaxation. You can also add accessories like outdoor lighting and a fan to this waterproofing system.
Sloping Cement Or Bricks
Although the ground beneath your deck will absorb as much water as it can, there will be standing water once it is soaked. This is particularly true if your gutters and roofing let water leak underneath your deck.
One way to avert pooling is to install brick or pour cement. Ensure that this spot slopes away from your house. If it doesn’t, the paving can worsen it.
If you are not able to lay bricks or cement, consider other options.
Construct a dry well or creek bed next to your deck so rainwater can run off somewhere. The dry well can gradually release the water into the ground. Another idea is to install gutters and pipes to catch water and transport it to a dry creek or well.
