Case study No.323, titled “The Mold Amongst Us,” has us examining the situation facing a Mr. Fred Ferguson.
Known as “Fungus Freddie” by his closer associates, Mr. Ferguson’s solution to pretty well any conflict is simply to douse the concern with water.
Got ants in the house? Spray ‘em with water. Got a headache or runny nose? Run your head under the tap. Got a backyard deck which regularly sees leaf and various tree-seed matter propelling down upon it? Hose it down.
So, besides having mushrooms growing under the kitchen sink, and family members regularly exhibiting flat hair days, Freddie owns a backyard deck with at least eight types of moss growing in between the planks. Although these moss species have garnered the interest of the local environmental institute, since the growths include the silene stenophylla, a moss dating back to the Paleolithic age, and otherwise thought to be extinct, the moisture contained by the moss – along with Fred’s regular waterings – have unfortunately encouraged premature joist rot.
As a result, a backyard deck that is only 20 years old will need to be replaced. Regular treated lumber, as opposed to the 60-year treated lumber used on wood foundations, is guaranteed to last 40 years, provided homeowners follow a pretty basic list of precautionary measures.
Rules No. 1 and No. 2: Seal any sawn edges with an end-cut preservative, then seal the project in its entirety with a paint or stain. Then, maintain this painted or stained finish with follow-up coatings every two-to-three years.
What to avoid? Treated posts should not be positioned in water (in the case of a dock), or buried in the ground. In other words, treated lumber should last 40 years if you can manage to keep it relatively dry.
Now, in an environment such as ours, where three consecutive days of sun is basically regarded as a divine intervention, how does a homeowner possibly keep their deck structure dry?
Well— achieving dry may not be always possible, however, there are installation methods or practices that if followed, can at least divert water or moisture so that it’s not pooling around your lumber.
Good practice No. 1: Avoid surface-screwing your treated decking planks. There’s a reason why lumber deterioration often starts with a black mouldy substance surrounding each screw, with hairline cracks radiating out from the screw heads. That’s because surface screws not only create mini pools of water around the screw insertion, but essentially funnel moisture into the core of the wood.
Avoiding this scenario means following either the deck-track, or Camo installation procedure.
The deck-track is a 40-inch length of perforated steel that gets nailed along your 2×10 or 2×8 joists, allowing the installer to fasten the decking planks from below.
The Camo system is a clamp type of tool that works in conjunction with a cordless drill (or corded, if you’re still doing things the old-fashioned way) and directs the camo screw into each side of the decking plank. Either way, surface water simply drains off the board, and you’re left with a beautiful, unblemished finish.
Good practice No. 2: Protect the 2×10 framework underneath with a joist guard. Available in four- or nine-inch strips of plastic, a joist-guard membrane protects the edge of the 2×10 framing lumber, ledger planks, and supporting beams underneath, from moisture, which would have been a big help to someone like Fungus Freddie. Mould and tree seedlings don’t stick so well to plastic, with this plastic shield allowing the owner to more easily brush out various tree debris from between the decking planks.
Good practice No. 3: Avoid your decking 4×4 or 6×6 supporting posts from coming in direct contact with the soil, or concrete pillars. Soil and concrete both absorb moisture, which will be passed on to any dry thing coming into contact with it.
So, use steel U-channels, or adjustable U-brackets to make that moisture break between products.
With these good practices now in Freddy’s toolbox, Case No. 323 was closed.