That’s a wrap

When building, we need to wrap or protect most of the lumber, while leaving a portion exposed so that the wood may be allowed to ìbreatheî or basically expel moisture at a more natural rate. Postmedia Network

I think the inventors of Baggies sandwich bags, and Saran Wrap, are two of the most intelligent and opportunist people in the world. Intelligent because they’ve managed to develop a lightweight, flexible, and user friendly manner of sealing and protecting foodstuffs. Opportunists because they’ve not only developed something useful, but have enabled us, as humans, to fulfill one of our most instinctive and powerful needs, and that’s the simple desire of wanting to wrap things.

What do we do with a newborn baby? Although it’s referred to as a swaddle, we’re essentially wrapping ‘em. Bloody finger? Wrap it. Christmas gifts, sprained ankle, hole in the car’s muffler? Wrap, wrap, wrap.

After supper the other night, I wrapped or bagged 10 different leftover items and tossed them in the fridge. Approximately 50 per cent of these items will see action in the immediate future, two to three things might be caught in time for use, with the last one or two items forgotten and allowed to develop into 15 types of mold. Regardless, they were all good wraps.

What do we do with a staff meeting that’s gone 30 minutes into overtime? We wrap it up. So, what do we do with basically any wood project or structure? Well, if you’re still not sure as to the theme of this week’s rant, for the good of the wood, you wrap it. For all intents and purposes, plywoods, basic framework, and wooden posts, will stick around for the long term if they’re kept dry. The strategy to keeping wood dry in a four season climate such as ours is challenging because wood is a product that naturally absorbs moisture. So, with a “dry season” unfortunately not forming part of the four seasons we experience, our plywoods and 2×4 framing lumber are always in a state where they’re retaining some level of humidity, regardless of the fact the lumber was kiln dried at some point in its production. As a result, we can’t simply saran wrap every piece of lumber because that would trap the humidity, which would lead to our lumber looking like the aforementioned science experiment regarding the 15 types of mold. Instead, we need to wrap or protect most of the lumber, while leaving a portion of the plywood or lumber exposed (with these exposed sides usually facing the interior of the building) so that the wood may be allowed to “breathe” or basically expel moisture at a more natural rate.

So, whether you’re building a shed, or 3000 sq. ft. home, we always protect the plywood walls with a house wrap. Because the interior, or what’s referred to as the warm side of a standard, insulated wall, must have a plastic vapor barrier, in order to prevent moisture from entering the wall cavity, the outside wall cannot be saran wrapped, or covered in the same manner, because that would trap the moisture already in the plywood, and stud framework. So, we cover the exterior wall with a house wrap, a product that sheds water, should rain or snow makes its way past the siding, but is still porous enough to allow the wood to breathe.

Our plywood roofs require the same type of protection. Although asphalt paper was for the longest time the product of choice, synthetic felts are the better product. Similar to a house wrap, synthetic roof felts shed water and breathe. However, they differ from house wraps in that they reflect UV light, and are far superior to paper felts because they can protect a roof for up to six months, which is a real bonus when inclement weather causes unforeseen delays.

Other areas in need of protection are the wooden framework around windows and doors. When the caulking around a window or door frame begins to shrink or crack, water infiltrates into the wall and puddles on the sill, leading to mold or rot. For this reason, we now wrap three out of the four sides of the wooden frames with a rubberized membrane.

Next week, more on wraps. Good building.

As published by the Standard-Freeholder
Handyman's Hints Standard-Freeholder Cornwall Ontario by Chris Emard

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