Sheathing plywood is an incredibly practical and long lasting material when it comes to building exteriors but rarely has it been lauded for its refined look. If you're one to frequent architectural magazines or Pinterest, you may have noticed in the past couple years the material showing up in high-end floor plans, embraced not only for the money it saves but also, surprisingly, the raw and knotted aesthetic.
A more traditional application of plywood
Plywood has been around for ages, purported to have existed in the age of ancient Egypt, and has served a highly functional purpose for centuries. Designers in the past such as the Eames and Gerald Summers made a name for themselves manipulating this all-purpose material, but these projects often used the highest quality of plywood varieties available like ash or walnut. So why now is even the cheapest plywood being propped and highlighted within the most beautiful of homes? Looking back at the history of ply and the economics tied to the material, we investigated these details in an attempt to find a solid explanation.
A renovation on a 100 year old home by NAAD, which is meant to possess an intentionally incomplete air (Inhabitat) Hem co-founder Petrus Palmer's kitchen with plywood adorned shelving and doors (source: Curbed) A knotty plywood home in Japan designed by Tomohiro Hata
Why ply? A short history lesson
Plywood technology has been around for centuries but only received its official patent in the year 1865, and finally went to mass market around the year 1910. This innovation involves harvesting and shaving a trunk on a large lathe and adhering the layers together. A plywood board's strength lies in the layering of these shavings (called veneer). The veneer's grains are arranged cross-wise so that the board's strength is significantly higher than a standard piece of hardwood. After the technology was marketed to the public, its utility proved to be endless: plywood's resistance to warp and weft helped standardize building construction and created exciting new opportunities in the field of furniture design. Miraculously, plywood technology continues to hold a crucial seat in the realms of architecture and design for its simple brilliance and cost-effectiveness.
Grade and pricing
One possible explanation for the recent embrace of sheathing plywood likely has to do with its significantly lower price point than high-grade ply.
Before going into pricing, it's important to clarify the grading of plywood. Plywood is organized in hardware stores by their physical grade: A, B, C, D (the lowest grade is called X). Grade A plywood is often smooth and sanded with no significant knots, splits or defects. Another common grade of plywood called BC dons a smooth Grade B face with Grade C inside and back. Another factor influencing price is the cross grain: often, ply with layers at a 90-degree rotation are less expensive than those with 30-degree rotations between layers, which adds more strength to the overall piece.
A breakdown of veneer grades (source)
The higher the grade of ply (aka the less you have to prep and finish pre-install), the more it is going to cost you. In a less-than-official survey I conducted comparing Grade A Baltic birch plywood to BC Grade sanded ply available at major hardware stores, a standard ¾" thick 4' x 8' sheathing ply could save you almost $20 per sheet (a potentially significant amount of savings when you think about how many ply sheets it takes to deck out your house). When all it potentially takes to refine your wood is a light sanding job, that knotty wood alternative starts to look that much more appealing.
What varieties are available?
If you want that wavy patterned wood look, Baltic birch or ash ply is going to be too smooth a surface for your space. Pine or fir are commonly used in lower grade plywoods and are most likely to offer you a higher contrast in color throughout the grain. Maple plywood is another alternative: a bit more light in color and cleaner but still available at a reasonable price (any suggestions for other attractive ply varieties are welcome in the comments section below).
It's also important to understand the pros and cons of different types of plywood. For one, there's hardwood ply—a great option for aesthetic standardization, but one of the more expensive options and these often feature a very thin face veneer (meaning, if you take your orbital sander to the top surface you may run the risk of creating an ugly circle or chipping the edges). If you opt for the very cheapest CDX ply (the most common plywood used for exterior projects), it's most likely going to take some patching, initial layers of polyurethane finish and extra sanding before you get the splinters out and create that smooth surface you're looking for. If your budget isn't too tight, you'll likely want to get Grade A, AB or BC Sanded Plywood in whatever wood variety you chose to ultimately save yourself the strain. BC plywood is a happy medium because it offers both a lower price point as well as a sanded finish on one side.
The topic of whether plywood is a sustainable resource or not largely has to do with three central issues, and if you're environmentally conscious it's good to be aware of these points.
1. Make sure timber isn't coming from endangered forests Check with your local supplier or in the aisle whether the wood has been certificated by the Forest Stewardship Council (FSC) or the Programme for the Endorsement of Forest Certification (PEFC) before purchasing.
2. Use plywood bonded with eco-friendly adhesives Plywood constructed with formaldehyde-free, soy-based adhesives like the ones used in PureBond ply ensure you're reducing pollution created during production.
3. Use plywood for long-lasting structures Reduce pollution by being smart about what you make: use plywood for projects with a shelf life longer than just a few years!
There's so much more to learn and absorb regarding plywood, so here are some helpful links to get you started on your exposed ply renovation project:
What's your take on the plywood trend? Have you used plywood to finish any interiors in your home? What are your favorite plywood varieties or methods for installation? Share your stories and photos of interesting plywood use in the comments below!