Renovation & Design

MIKE HOLMES: Fight warp and sag in wooden fences, gates

Postmedia/If you have a wooden fence with a wooden gate chances are one or both is going to sag, lean, warp or twist.
Postmedia/The general rule here is, the thicker the wood, the less likely it will warp.

IT'S a problem most homeowners have to come to terms with eventually: If you have a wooden fence with a wooden gate, chances are one or both is going to sag, lean, warp or twist. Your brand-new fence is a model of perfection, and then slowly over the next few years, it can start to distort, or if you are really unlucky, the thing just becomes a train wreck from the word 'go.' Either way, the result is the same: The gate becomes so far out of square it doesn't close shut, fence boards start looking like bananas and the whole thing resembles the Leaning Tower of Pisa.

What went wrong? The answer isn't so straightforward, because there are many factors at play when dealing with wood, especially wood that's going to be exposed to the elements. Simply put, wood has a mind of its own. Take a perfectly straight plank right from the lumber mill and leave it outside for a few days in the sun and watch it quickly become less than straight as it dries out. The wood-grain pattern and position of the knots begin to pull at the perfectly milled shape one way or the other. It can be very frustrating.

The quality of the wood is a factor, and so is the overall wetness of the wood, the kiln drying process and how long the wood has been sitting around before use. Also, let's not forget humidity and climatic conditions through all the steps from living tree to your gate and fence. Generally speaking, cedar fares better than pressure-treated wood, but, considering the factors mentioned above, as well as others, such as the size of the tree that the planks came from, it really becomes the luck of the draw if the wood behaves itself or not.

There are things that can be done to limit the amount of warping. If it's a smaller job, some contractors will insist on hand-picking each piece and checking for cracks and signs of warping and crowning. Understanding how the grain can affect a piece of wood can also help in the selection process, but it takes some experience to understand the relationship of cause and effect.

There are some simple tips out there, such as when choosing posts, look at the ends. Find posts where the tree rings are centred in the middle of the post; these tend to bend and twist less than posts made from the outer edges of the tree.

For large projects, when hand-selecting your wood isn't a viable option, you might consider using larger dimensional lumber in key areas. The general rule here is, the thicker the wood, the less likely it will warp. Instead of 4 by 4 posts, if possible go with 6 by 6 posts. In this case, the extra size makes a huge difference. It's a smart place to invest a little extra in your fence, because if your posts distort after they have been set in the ground with concrete, needless to say they are extremely difficult to replace.

Another simple trick in limiting wood warp is to install new wood as soon as it arrives on the job site. If your face boards are being delivered from the lumberyard, they will be tightly packed together with straps. This keeps the wood relatively straight. If it seems overly wet, the bundle will help to keep most of the shipment from drying out too quickly. Once the straps are cut away, it becomes a race against time to get each piece installed and secure. Secure means both ends of the board are attached, and if the planks are longer than four or five feet, they should also be attached to a middle horizontal fence rail. Securing the face board in the middle prevents the plank from bowing inward or outward, or curving from side to side.

Sagging gates are so common that some gate-latch hardware is designed to compensate for the onset of sag, when the latch eventually comes out of alignment. This feature doesn't fix the sag problem; it just makes the latch function a little longer, until the whole gate eventually sags so far out of square that both the latch and gate stop working.

The cantilevered weight of the gate is held in place by just a few hinge screws secured to a single gatepost. This means the forces of gravity are constantly at work to pull the outer edge of the gate downward. The gatepost, the hinges, and the gate itself are all subject to being pulled out of alignment. If you think of these areas like a chain, the whole gate system is only as strong as its weakest link.

If you suffer from gate sag, and want to do something about it, let's look at the three areas that all need to be seriously beefed up.

First, the gatepost. This is the most overlooked part of the gate. If it has any flex, and you add the cantilevering weight of the gate, you will have sag. This is another reason to upgrade to a nice, sturdy 6 by 6.

But a beefed-up post is only as good as the hole it's in. Just as with any structure, fence posts, and especially the gatepost, need to have a solid foundation. This means the hole must be at a proper depth (depending on your regional building code) and secured using a Sonotube and concrete.

The next link in the chain are the hinges. The average set of gate hinges can handle the weight of a gate that's about 50 to 75 pounds. In other words, it's working pretty much at designed capacity. There is no rule that says you must use only two hinges. Hinges are fairly inexpensive, so add an extra one, or even two. More hinges will support the cantilevered weight with ease for the life of your gate.

Make sure you have taken every possible countermeasure to keep your posts from warping, twisting and flexing, because these can't be repaired once they are installed. As for the rest of your fence, just remember that, no matter what you do, a few pieces of wood will want to rebel. Be prepared to replace the odd troublemaker down the road to keep your fence looking right.

-- Postmedia News

Catch Mike in his new series, Holmes Inspection, airing Thursdays at 7 CT on HGTV. For more information, visit For more information on home renovations, visit


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