Composite decking is composed of wood and HDPE but does not weigh the same amount as wood decking. How much more composite decking weighs than wood decking depends on the type of composite decking. The blended material formula and the decking designing can impact how much the decking will weigh.
Treated 5/4 x 6 wood decking on average weighs 1.59 lbs a lineal foot, an equally sized composite weighs 2.3 lbs. Making composite decking on average 45% heavier than pressure-treated wood decking. A standard 12′ treated decking board weighing 19.08 lbs, with the same composite board 27.6 lbs.
Of course, those are averages. When you are carrying the decking around to the backyard to build a deck, it may weigh more or less depending on a few factors.
Wood decking weight, in particular, depends significantly on how wet it is. Is it fresh from the mill, still heavy with treatment, or has it been drying in the sun? Has it recently rained, soaking the decking? Moisture plays a much smaller role with composite decking.
On the flip side, there are several ways that composite decking can be made lighter. Minimizing the weight difference between composite and wood decking, resulting in one brand of composite decking being significantly heavier than another.
Let’s move away from talking about averages to more specific decking board weights. For we can speak more accurately of which ones are heavier and why some are lighter. Below is a chart of individual composite decking weights by brands and lines comparing them with wood decking Cedar and Pressure Treated pine.
|Decking||Weight per Lineal Foot [Lbs]||12′ Deck Board Weight [Lbs]|
|Western Red Cedar 5/4×6″||0.88||10.56|
|Treated Pine 5/4×6″||1.59||19.08|
|Fortress Apex PVC||1.58||18.9|
|Fiberon Paramount PVC||1.58||18.9|
Quick note, wood being a natural product, will vary from board to board in weight. The board may be pine, but how it grows will impact its density. Also, as we will discuss more later, wood is not dependable one weight. Moisture level plays a huge role in how much wood decking weighs, where composite’s weight increases little.
If you want light decking, cedar is the decking for you, close to half the weight of pressure-treated pine and almost a third of Deckorators WPC decking weight. It is the lightest of the decking.
Technically not composite decking but often included is PVC decking. A great low maintenance alternative to wood decking. PVC decking is very similar to wood decking in weight. With some decking like Azek weighing even less than treated pine. Even Deckorators’ mineral-based decking is only fractionally heavier. Making PVC decking an excellent choice for a lighter decking product.
With its lighter bamboo and engineered to reduce weight, Fortress Infinity is one of the lightest composite deckings on the market. It was developed in South Africa, where air delivery to remote locations is more common, makes decking weight more critical than in North America.
Interestingly the weight of the decking and its strength does not coincide. In the middle of composite decking for weight, Trex often scored higher in composite decking strength. Showing that weight is not a clear indication of strength for composite decking.
Composite decking design is more critical for strength than density.
Composite decking strength and weight are impacted by the design of the decking. This leads us to our next point.
Composite Decking Design Impacting Weight.
There are two main ways to reduce composite decking weight.
- Reduce material by Scalloping the underside of the decking
- Decking material Formula
Scalloped Composite Deck Boards Weigh Less
Initially, to reduce costs, scallops decking also has the added benefit of reducing weight. The simplest is three plows or dado cuts in the underside of the decking. Reducing the decking weight by reducing the material with minimal impact on the strength and appearance of the decking.
The difference is easily seen with Armadillo’s grooved and solid decking options. Their solid decking weighs 2.3 lbs per foot, but the scallops reducing the weight down to 1.89 lbs. Lower the decking weight by 20%, just by removing unnecessary weight on the underside of the decking.
Fortress has gone to the next level with Infinity decking, with an I joist design. The decking strengthens with four small I beams, one of the strongest shapes in construction while reducing the decking weight.
The same floor design is used with most new houses, being built with I joists instead of the traditional solid joist. A design that has reduced weight and ease of construction while increasing the floors’ strength and consistency.
Lighter Composite Material
Fortress has further reduced weight by the material included in their decking.
“The foam core reinforced with bamboo is 45% lighter than composite decking making it easy to work with.”Fortress Apex
Wood fibres are commonly used in the manufacturing of composite decking. Commonly pine sawdust is used in the manufacturing of composite decking. Fortress uses bamboo fibres, both for its superior strength and weight.
A quick comparison of bamboo and pine weight shows the advantage.
Bamboo weighing as much as 25% less than Pine. Further reducing the overall weight of composite decking.
PVC decking is also consistently lighter than composite decking. The fully synthetic material weighing less than even bamboo composite.
Moisture Can Increase the Weight of Wood Decking
Wood decking, especially pine, readily absorbs water, dramatically increasing weight. Freshly treated pine decking can weigh as much as 2.79 lbs a Linear Foot, with a 12′ board weighing 33.5 lbs. Just by adding water, the decking’s weight is increased by as much as 75%.
If enough water is absorbed, treated decking will actually weigh more than composite decking.
Weigh change does not happen with composite decking. Regardless of how much it rains, composite decking will weigh the same. In fact, Trex decking has no dimensional change from water. Fortress Infinity water absorption after 28 days is only 0.6%. Barely register in increase weight.
So unlike wood with significant swings in weight, composite decking is constant.