Wood fences can make a fine addition to your property. However, when it comes to installation, one of the most common questions we often get is, do wood fences shrink?
The answer is yes, wood fence boards will shrink, as well as swell, in response to the weather conditions in your area. The extent of the shrinkage and the swelling also varies according to the type of wood used to build the fence as some species respond more to climate conditions than others.
Let’s look at the reasons wood fences shrink, how different wood species compare, how to account for shrinkage when you’re building the fence, and more.
I also looked at “How long wood fences last” here.
Why Do Wood Fences Shrink
As a material, it’s natural for wood to respond to different weather conditions. This response refers to a change in the physical dimensions or shape of the wood fence board.
As such, wood shrinks when humidity is low and expands when humidity is high. Additionally, wood can splinter and crack when the water content freezes in winter.
From this, we can conclude that moisture is the main culprit behind wood fences shrinkage, swelling, and warping, ultimately causing them to lose their original charm.
Which Type of Wood Can Resist Shrinkage
While it’s natural for wood to respond to moisture, there are certain wood that are moisture-proof or at least moisture-resistant. Before we talk about these species, we’ll briefly explain how moisture affects wood’s structure.
Wood, as pretty much any plant, is made up of individual cells that contract when they lose water and expand when they absorb it. Since fence boards are made of wood, they’ll shrink and swell in response to moisture in a similar way.
However, some types of wood have cell structures that are more resistant to moisture, so their corresponding fences don’t shrink to the same extent.
Examples of wood species that can resist moisture include cedar and redwood. The reason for this is that their cells are small in size and have thin walls.
As a result, the cells of cedar and redwood don’t undergo significant shape changes, so weather conditions don’t really affect them.
On the other hand, pressure-treated pine – which is commonly used in building fences due to its higher availability and cheaper price – can undergo notable shrinkage. What’s more, this shrinking can cause cracks, curling, twisting, and warping. You probably will never see that happen with cedar and redwood.
Does Design Contribute to Wood Fence Shrinkage
Your wood fence will still shrink if you apply an improper design, even if you build its boards using a moisture-resistant wood species such as cedar or redwood.
So how can a design be shrinkage-proof? Well, you can lay out the boards in a way that minimizes the negative effects of shrinkage to maximize privacy.
The most effective design is a board-over-board arrangement. This means overlapping the boards on alternating sides of the rail.
Typically, when the overlap is 1 inch wide, it’s enough to prevent prying eyes from peeking through your fence. It can handle shrinking even in the driest weather, and at the same time, it offers sufficient space to accommodate expansion in wet weather.
If you’re interested in a gapped look, you can also try accounting for the fence boards shrinking in your design before building.
In this case, you’ll start installing the boards next to each other without any gaps. This way, when the wood boards shrink, the fence will have about 1/4-inch wide gaps when it dries out.
Having the fence designed with gaps right from the beginning means the gaps will grow wider in dry weather. There are many instances where professionals use a 16 penny nail as a gap standard (about 3.5 inches long) when setting wood boards, only to get called back to reset them.
Should there be a Gap between Wood Fence Pickets
The answer here depends on your preference when it comes to purpose and style.
If you’re building the fence for improved privacy, then you have two main options to choose from:
- A solid fence (that ensures total privacy) or
- A board-on-board fence (also known as shadowbox fence or alternating fence) that offers slightly less privacy but offers decent air circulation.
For the solid fence, you need to install the wood boards with no gaps or with a 3/8 to 1/4 inch space between each other to accommodate wood shrinkage and expansion when exposed to varying climate conditions.
If you opt for the board-on-board style, then you’ll arrange the fence boards alternating on each side of the rail. This way, they end up with a minimum of 1-inch overlap on each side of the pickets.
If your primary purpose is to keep kids or pets safe, then follow the standard spacing of railing boards. This is less than 4 inches. And it prevents a 4-inch ball from passing through the fence gaps.
How Long Do Wood Fences Last
On average, a wood fence offers a lifespan of 15 years. You can extend the longevity of your wood fence up to 20 years if you provide proper maintenance. Here are some tips:
- Do yearly inspections to ensure there isn’t any rot or damage. Be sure to replace any broken pickets, tighten loose screws, and hammer in any nails sticking out.
- If you’re using pressure-treated wood, make sure you seal it against moisture.
- Clean your fence every 2 to 5 years. Don’t forget to reseal it after cleaning.
So, do wood fences shrink? We can safely say that the answer is yes; wood fence boards will shrink, as well as expand, in response to the weather conditions where you live. The extent of contracting and expanding also depe