Deck Finishing and Carpentry
When holding down deck boards, you can use zinc-coated screws or powder-coated screws. You might think it doesn’t matter. But you would be wrong! This short video explains the three reasons why you should use powder-coated screws, even if they are 3 times as expensive.
Many decks get slippery in the winter and this causes a very serious hazard for you, your parents, and your kids. The answer is to carefully scrub in fungicide and destroy the fungus that causes the hazard. This short video explains how to do this.
So your deck is old and doesn’t look so good. Should you use opaque (or solid color stain) or paint? How do they cope comparatively with sunlight, moisture, foot wear, cost and wear mode? Click on to find out.
Ever wondered why decks go gray? What is that gray stuff? Is it dirt, sun damage, or fungus? Find out!
There are several reasons why we think your deck is worth some care and maintenance:
All in all, it makes sense to take care of your deck.
It might seem self-serving for us to say this, but we really believe that keeping your deck stained is the best thing you can do. The wood has to remain protected from UV and water.
Get it refinished when it starts to go gray.
That gray is mostly fungus and it’s eating up the soft tissue between the tree rings (“grain”) which exposes the harder grain which leads to splinters. The wood has lost its waterproof coating as the stain has been damaged by the UV and rot starts to penetrate and weaken the wood. The UV from the sun is also drying the wood out. Don’t leave it the deck; it’s just not worth it. Plan on having it stained every 3-4 years (or every year or two with oil based stains which are much less resistant to UV).
Look out for “Deck Destroyers”
The two principal deck destroyers are surface damage (like mold) and deep damage (like rot and pests). Let’s look at them in turn:
Dealing with Surface Mold
There are four types of mold under the deck to look out for:
1. Black mold. This is mildew and can be seen as lots of black spots. It is fairly normal to see this. Sometimes, if the deck is very wet, the whole bottom of the deck boards is black. A spray of dilute bleach under the deck is a simple treatment to keep this under control.
2. White mold. This is a fungus called Mycelium and it is a sign that the deck is wet and staying wet. Often you see this where water “stands” where deck boards meet the joists. This indicates that a problem will appear in the next ten years. If you can reach it, it is best to pressure wash off the fungus and then kill it with dilute bleach.
3. Green mold. This is the worst rot and needs immediate attention. Usually it is a thin film of green mold, but it can get far worse within a few years. I have seen a deck covered in thick green mold under and on the deck; you could barely walk on it without your feet going through. Best to pressure wash off the green mold and apply chemicals to stop it coming back.
Dealing with Deep Rot and Pests
There are four types of deck board damage to look out for:
1. Dry rot. You will be familiar with this. This is rotting, usually first seen at the ends of deck boards as a softness and brown discoloration, often dampness. Replace the board when the end starts to get springy. Or you can use Copper Green chemical (very toxic, respirator needed).
2. Brown rot. This is quite rare, and is a cubic break-up of the wood. Treat with chemicals or replace the board.
3. Termites. When wood gets damp (such as, when the stain no longer keeps the water from entering the wood), termites can burrow into it. They tend to enter at the ends of boards and munch their way down the grain, then they find another board. Many people think they are like piranha but they are not that fast. Every house has termites; you just don’t realize it. There are different types of termites. Some fly around and then drop their wings and enter the wood. Others can make their own “ladder” and climb vertically upwards towards your deck! Look out for discarded wings, small brown wood particles pushed out of holes in the wood, or distinctive fungus-like vertical tubes under your deck. Treat with “Orange Oil”, tent the deck and house with chemicals for 3 days, or have a pest-destroyer come along with their microwave wand.
4. Beetles. Fairly rare, they leave a single pinprick entry point about 1/32 inch in diameter. Easy to miss. Usually not that destructive. Apply killing chemicals to entry point.
You can find more information and pictures in our handy pdf called “Deck Destroyers” from our website.
Decks dry out if not looked after and joints start to fail. This can affect safety and I suggest you keep a “weather eye” out for this.
Brace handrails when they become wobbly.
In the old days, handrails were bolted into the fascia below the deck level and in turn the fascia was connected to the deck joists via a few nails banged into their end-grain. Over the years, with all that leverage between the top of the handrail and the bottom where the nails are, the handrails can get a bit wobbly. If it worries you (and if you have a long drop!) then consider bracing handrails in the middle of a long span. (Corners are often much more rigid). We use blocks where the handrail post is bolted into the joist at 90˚ using an intermediate wood block. Or we bolt an extension to the handrail and then use a diagonal brace which connects the bottom of the handrail post to the joist. If the deck is far above the ground and the ground below is slopey, however, it can be very difficult to use this sort of brace, so a diagonal brace through the deck from above has to be used. There are some pictures of these solutions on our website (look under “deck carpentry.”)
Corners of handrails can be a bit “dodgy”. A 90˚ angle brace lag-bolted into both handrail caps on the corner usually makes everything a lot safer.
Insert screws where nails pop up.
If you have boards that are lifting, i.e. the ends are warping upwards, or you have nails that are popping out, then a solution is to bang down the nails and insert a screw between them. Some people have tried to remove nails using a claw hammer and then put a screw down the hole. But the hole has often been widened by the rot and the screw barely holds. Some try banging down the nails, but they always come back out within a month – the reason is that walking on the boards gently pushes the nails back up again as they have lost their friction. The answer is to put a screw between two nails. It makes a new hole so avoids the issue of existing rot. And it holds the boards down so the nails don’t come out. If you are screwing at the end of a board, either pre-drill the hole for every screw (to avoid cracking), or angle the screw and put the screw in an extra half inch from the end. You may need to use a longer screw to get through to some good wood. We recommend powder-coated screws, rather than the usual zinc-plated screws. The former last a lot longer and don’t rust, though they do cost three times the price. Well worth it.
We find it is usually enough to put screws into every board-end and every other joist – no need for every joist. If your deck is old, you might want to buy a box of 1,000 screws and allocate two afternoons to the job. Oh, and don’t forget to charge up a few cordless batteries before you start (you will need a new one every 20 minutes), and use knee-pads.
Mechanical damage caused by your furniture and other contractors can be an issue worth looking out for before it happens as they are hard to fix.
Put feet on bottom of chair legs.
Metal furniture and all forms of metal-to-wood contact are always a problem. With metal furniture, I suggest you check that none of the plastic feet have come off. You can get replacements at Home Depot or Ace Hardware.
Don’t drag stuff across deck.
Several times year we get calls from people where they, or their landscape or interior contractors, have dragged something across the deck and scored the wood. This obviously goes through the stain and leaves the wood exposed. Look out for: gardeners rolling planters across the deck, furniture movers dragging filing cabinets over it, window washers not having soft feet on their ladders, contractors working inside taking in heavy materials, and the golfer in the family walking on the decks in golf shoes!
It’s water and UV that really damage decks. Moisture is one thing, water itself (in large quantities!) is quite another. Here are a few suggestions for you.
Put feet under planters.
“Standing water” (water that never quite dries out and can’t easily escape anywhere) is the number one enemy of decks. Most people overwater plants and the planters sit directly on the surface, leaving a wet patch underneath. If you can elevate the planter, the wood has a chance of drying out. You can get plastic or ceramic feet, or cruciform wood structures with wheels, or planters with wheels at your local hardware store (try the gardening section). You can also see if you are overwatering and can adjust your watering or irrigation system.
Fix leaky gutters.
Not only will a leaky gutter cascade vast amounts of water onto the deck, leaving it damp all winter, but the impact will probably rip off the stain and leave a line about 6” wide across the deck. We have seen this in a fair number of decks, and now I know what to look out for (and you do, too!) The most obvious point is right under the corner of a roof, where the water cascades around so fast it overspills on the corner and deluges down. Or, if you have a tall wall that faces into the wind, water can hit the wall and cascade down the wall, and then drop where a patio door is and damage your deck right there; a small deflector strip above the door can be enough to solve this issue.
Avoid irrigation spray on the deck.
Make sure that your lawn sprinklers do not douse your deck as they will leave precipitated minerals (i.e. a white mark) as the water evaporates. Water can also soften the stain, making it vulnerable to being scratched off. I suggest you make sure your landscape contractor (or you!) use 180˚ sprinkler heads facing away from the deck, not 360˚ heads, close to the deck.
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