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What Is Warping And What Can Be Done To Prevent It?

Post 2 of 110

One of the defining characteristics of a piece of timber is that it’s made of thousands of tiny fibres, which are built steadily over the lifespan of the tree. The speed at which the tree grows will affect how densely-packed these fibres are, and thus how tough the resultant timber is. As a result, we need to wait longer for the harder materials, like those stocked by oak flooring North Wales specialists.

On the other hand, quick-growing softwoods like pine can be brought in relatively cheaply. Since there are more natural resources available to the tree during summer than there are during winter, growth tends to occur more quickly, and thus we’re able to judge how old a tree is by counting the ‘rings’ of darkened timber which mark seasonal changes in the speed of growth.

When used as a building material, there’s a definite downside to timber, and that’s warping. Warping is a phenomenon which occurs when the moisture content of the wood changes unevenly. If one part suddenly becomes drier than another, it’ll contract. This will result in changes in the shape of the timber, and thus a section of floorboard that was meant to lie flat will suddenly begin to bend. In some cases, this effect can be a cosmetic annoyance; in others, it can seriously impede the function of the item that’s warping.

What influences wood warping?

There are four factors which influence the rate of warping. Control for each of them, and the rate of warping will be reduced.

Firstly, thicker pieces of wood tend to be more resistant to warping than thinner ones. This is for the obvious reason that small amounts of warping won’t be able to drag the rest of the body of timber out of alignment quite so easily. Moreover, changes in moisture are more likely to be even throughout the plank.

Another factor that’ll alter the rate of warping is the way that the wood is finished. A protective layer of paint or wood finish will prevent moisture from creeping into the fibres, or escaping from them.

We should also consider the grain orientation. The end grain of the wood will warp more easily, because there are more opportunities for moisture to escape.

Air temperature this is a big one, as obviously when things heat up, moisture will have the energy it needs to move from one place to another. This is a particular concern in outdoor environments, where the temperature is constantly fluctuating. If you have an area of fencing or a section of patio decking that’s exposed to constant sunshine, you can be sure to that it’s more vulnerable to warping. Treat it accordingly.


The way that a piece of timber is sawn will have an effect on the potential for warping, as it’ll expose different areas of the grain. The most economical means of sawing, unfortunately, are also those that provide the greatest potential for warping to occur, and so timber suppliers must decide between sturdiness and economy.

A ‘plain sawn’ piece of timber is one where the planks are sawn flat across the tree. This is the cheapest method, but it’s one where the rings intersect each plank at a shallow angle, allowing for greater warping.

A ‘rift sawn’ approach, on the other hand, ensures that each plank is perfectly sawn so that the rings pass through at an angle that’s around 45°, like the spokes of a bicycle wheel This creates a lot of waste, as the bits of timber between the planks must be discarded, and so it’s uncommon.

Between these two extremes lies a ‘quarter sawn’ compromise. This takes a quarter cross-section of the tree and points each plank toward the centre, but so that they are flat against one another. This allows for a steeper angle of intersection, but guards against the waste that might occur. When the timber is rift-sawn. As such, it’s more common than the more extreme variety of sawing.

In conclusion

From the perspective of the end user, the most important consideration should be where the timber is procured from. Opt for a reputable supplier, and you’ll stand a far greater chance of receiving timber that’s been carefully harvested and stacked, and whose storage conditions have been carefully monitored for spikes in humidity and temperature. You’ll be able to secure timber from one of the handful of reputable building material and plumber’s merchants North Wales has to offer. It’s also worth stacking a few planks on a suitably flat surface to ensure that it lies flat from end to end.