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How to Prevent Your Deck From Rotting

You have a beautiful deck on which you love spending time. It’s only natural you want to do your best to keep it clean and ensure it has a long life. You can do several things to make this happen, including regular maintenance, keeping it clean, being watchful for mould, and checking for rot.

wooden floor decayed by dry rot

We’ll show you some options to ensure your deck stays dry, mildew-free and rot-free. Also, these are the ways to prevent pesky insects from getting in (and under) your deck and its substructure. No matter whether you have a deck made out of timber or composite, there are steps you can take to make sure your deck has longevity.   

Composite vs. Timber 

Composite decks are made of recycled plastic and wood filler. Timber decks are made from pressure-treated pine or could be made from more sustainable materials, such as cedar, ipê, or even bamboo. Your substructure will be made from timber regardless of your deck surface. Protecting that part of your deck so it remains strong, durable, and in top shape for years to come is essential.

composite deck with swimming pool at residential house

Keeping Timber Inspected 

Every six months or so is an opportune time to check the surface and structure of your deck. Inspect for signs of mould. If your deck is discoloured or feels soft, there is a chance that your timber may be rotting. Both wet rot and dry rot can affect your deck. What’s the difference?

Generally, moisture creates wet and dry rot, but an atmospheric moisture content of around 20% contributes to dry rot. Frequently, dry rot starts from wet conditions. Moisture, a leak, or poorly managed drainage will encourage the mildewing and rotting of timber. Installing a good deck drainage system is important to prevent moisture penetration.

dry rotted wood deck

It’s fairly easy to tell when wet rot has occurred. This type of rot will usually discolour your deck, often making the affected area darker and eventually appearing dark grey or black. Dry rot will not only decay your deck but also make it extraordinarily fragile. Usually, it will lighten the timber due to the presence of fungi called mycelium.

Consider Using Rot-resistant Timber

We referenced some excellent lumber materials before, but there are many to check out if you want a mould and rot-resistant deck. Cedar, redwood, and teak are all intelligent choices. Trex composite decking is another smart option for those who also prioritize sustainability.  

Although most of Australia is relatively arid, it’s important to consider your deck during the cooler and rainier months. In addition, wet weather can compromise your deck, and the area underneath and create a bad scenario for rot to appear. Once rot sets in, it can weaken your deck by slowly damaging the timber.

Creating a dry space under your deck is not only useful, but it is also essential. Ensure you waterproof this area to stay mildew-free and protect whatever you may have stored there. Downspouts, gutters, and flanges are all advantageous installations to help this environment stay dry.

Waterproofing Your New Deck

There are various ways to keep your under-deck area dry and several methods to waterproof your deck. Let’s look at flanges first. Flanges will act as little gutters and prevent water from accumulating under your deck boards, thus keeping the underneath dry. They are usually made of rubber and need regular inspections to ensure they perform.

An under-deck ceiling may also work well, but unfortunately, this system catches water below the joists. An above-joist system is much better because it diverts moisture away before it can rot the joists and cause problems to the deck’s structure.

The best system is an under-deck drainage system designed to filter water away from your deck joists and beams. You can easily install this system when constructing your new deck. The investment is worthwhile and lasts for the long term. It is placed over the joists so they stay dry and moisture-free. 

waterproofed wood deck

The Job of Joists

Joists are the horizontal support structures that are directly under the deck. They usually run perpendicular to the deck surface boards. The beams are the vertical “legs” that support everything else and are typically anchored by cement. 

wood deck joists

When joists get wet, the water is often trapped by the small space and left with very little room to breathe. Applying some protection, such as flashing or butyl tape, is tantamount to extending the life of your joists. The tape will help not only in the reduction of moisture but it will keep your decking screws and fasteners in place for longer.

Although there are different types of tape, such as acrylic, silicone, and rubber butyl, you’ll likely discover butyl will give you the best fit. It doesn’t bunch up, applies easily, and has a lasting warranty, so you know you’re using a quality product.

Butyl tape is known for various uses. It’s perfect for RVs and ductwork, and some home repairs. Regarding your deck’s timber substructure, it is the best time to apply butyl tape when it is newly constructed. Besides being the easiest time to put in place, you’re starting with a sturdy (and dry) timber support base and a proven method to keep moisture out.

The Deal With Sealing 

What else can you do besides protecting the underside of your deck by applying joist tape and performing a general cleaning (with inspection) regularly? Here are a few suggestions.

We recommend cleaning your deck every six months. If it is Trex composite, use a bristle brush and either a homemade cleaner or a commercial one for composite decking. Scrub any stains away. After it thoroughly dries, you can put back your furniture and plants. If you have a Trex deck, you’re ready to go!

Caucasian man cleans a wooden deck

For those of you with timber decks, a sealant will help to preserve your deck. Apply a high calibre sealant, using either one or two coats depending on your needs, and let dry. Then return furnishings and anything else that you might have on your deck. Using a sealant will protect against harsh weather and help guarantee your deck has a longer life.

sealant can brush on partially stained wood deck

Dealing With Rot – If It Happens 

Sealing your deck will significantly help to prevent any rot. If you discover rot occurring, there are several things you can do.

First, how extensive is the rot? Where is it? Has it weakened the area which supports your deck’s surface? It’s crucial to assess this, as this will determine how you treat the rot.

Remove your deck’s surface boards over the suspected rotted area to see if any mould is present below. You might be able to apply a fungicide along with a filler or epoxy to strengthen where the rot was. You will want to once again clean and seal the repaired part.

If the timber is spongy and crumbles to the touch or when prodded with a claw tool, then it may be time to replace it. Using a chisel, remove the affected timber and apply the new material. Additionally, the application of fungicide is optimum for thwarting future rot.

In Conclusion

Keeping your deck clean and in good repair – and regularly inspecting for wet and dry rot is the best thing you can do. An under-deck drainage system, flashing tape, and sealing your timber are all good practices. Remember, the prevention of rot is much easier than cleaning it up. Also, you don’t want anything to take away from your fun in the sun!