HPVA Plywood

The natural beauty of wood makes for attractive, functional and comfortable furniture. Contrast in the grain, or even in different woods used together, can provide interesting patterns that can be mesmerizing to look at. Making the right choice in wood selection is a key part of making any piece of quality furniture.

We’re all familiar with how commercially made furniture is being largely made of vinyl-coated particle board, following the IKEA model. It’s rare to find much furniture made out of solid hardwood any more. That’s largely due to cost, as furniture manufacturers are battling rising material and labor costs, in a market which isn’t willing to pay more for their products, especially while inexpensive options exist.

That doesn’t mean that you and I have to follow their example though. Even if you can’t afford to make your furniture project out of 100% hardwood, there are other options, rather than stooping to using particle board. One of the best of these is HPVA plywood.

Hardwood plywood has long been used by the furniture industry and cabinetmakers to produce quality pieces, without having to use solid hardwood. When you want the best possible plywood for a furniture project, you want to make sure you order HPVA plywood. HPVA refers to grading by the “Hardwood Plywood and Veneer Association,” an organization consisting of hardwood plywood and veneer manufacturers who produce 90% of the hardwood plywood stock panels and hardwood veneers made in North America.

The HPVA is an ANSI (American National standards Institute) accredited organization. As such, it provides the only true standard for plywood quality there is in the industry. While individual manufacturers may create their own standards, they are not widely recognized or consistent across the industry.

Even though standards developed by the HPVA are voluntary in nature, they are still widely recognized and accepted. This given the standards credibility, ensuring that when you buy a product rated via the HPVA standard, you’ll know what you are getting.

Properly stated, the plywood standard is called the ANSI/HPVA HP-1-calendar year standard. This is often shortened, leaving off the calendar year that the standard was adopted. Some people try to shorten it even farther, calling it the “ANSI” standard, but that is incorrect. There are literally hundreds of ANSI standards, written by ANSI affiliates, and all but one of them deals with things other than plywood quality.

Since this is wood we are talking about, we must realize that grading the wood to any standard is not an exact science. While the standard attempts to provide an objective measure of the quality of the wood veneer, there is always some subjectivity as to the overall appearance of a particular piece. There will always be specific pieces which are difficult to grade, because their overall appearance makes them fall into the grey area between one grade and another. This creates an overlap, which can make pieces of a lower grade actually be more attractive than those of a better grade.

It is important to select pieces of plywood based upon their overall appearance, even though they might not fit the grade that has been specified.

More than anything, the grades are designed to take into consideration specific flaws in the surface of the veneer. Maximum numbers and maximum area covered by these flaws are written into the specification. This is the non-subjective part of grading the veneer’s appearance. But even within those limitations, it can be difficult to determine which grade a particular sheet of veneer or plywood should fall under.

The Basic Grading System

Separate grading systems are defined for the face and back sides of the plywood. Rarely is it necessary to have both sides of the plywood visible in a piece of furniture, so the back side allows for considerably more and more obvious defects than the face side. Manufacturers are aware of this and will save their best veneers for use on the face side.

Although the grading system gives specific numbers of defects, such as the number and size of knotholes allowed, it is necessary for the user of the plywood to inspect each piece, determining its overall condition, appearance and whether or not it is acceptable for their intended use.

Face Side

The face side of the plywood is graded on four levels, identified by the letters A through D, with A being the highest level and D being the lowest.

Grade A – Veneer should be matched for color and grain. All splices should be book-matched, creating an attractive visual appearance. No abrupt color changes are allowed between pairs of book-matched veneers. No knots, even sound knots or repaired knots are allowed; nor are spots of rough-cut veneer. However, slight mineral streaking and/or vine marks are allowed. Some pin knots or small burls are allowed, with the actual quantity depending on the species of wood.

Wood Type *	Max Number	Max Burl Size
Ash, birch, maple and poplar	10	3/8”
Mahogany, anigre and sapele	10	3/8”
AA Grade Mahogany, anigre and sapele	6	1/4”
Red & white oak	12	3/8”
Hickory	64	3/8”
Walnut and cherry	24	3/8”

Note * – In all cases, this refers to face veneer that is rotary cut, quarter cut, or plain sliced.

Grade B – Face veneer should be matched for color, but it is not required for it to be book matched or otherwise matched for grain. While similar to A grade face veneers, B grade does allow for sound or repaired knots, and some lightly rough cut veneer. The total number of repaired knots is 1 per 8 sq. ft. and 4 per sheet, with a maximum size of 1/8” x 1/4”. Slight mineral streaks vine marks are also allowed.

Wood Type *	Max Number	Max Burl Size	Repaired Knot Max Size
Ash, birch, maple and poplar	10	3/8”	1/8” x 1/4”
Mahogany, anigre and sapele	10	3/8”	1/8” x 1/4”
Red & white oak	12	3/8”	1/2” x 1/2”
Hickory	64	3/8”	3/8” x 1/8”
Walnut and cherry	24	3/8”	3/8 “ x 1/8”

Note * – In all cases, this refers to face veneer that is rotary cut, quarter cut, or plain sliced.

Grade C – Allows for unlimited pin knots and small burls. Solid and repaired knots are also allowed, with a maximum of 1 per 4 sq. ft. and 8 per panel. Unlimited vine and mineral marks are allowed. However, a smooth sound finish is required.

Wood Type *	Burl & Pin Knot	Repaired Knot Max Size
Ash, birch, maple and poplar	Unlimited	1/2” x 1/2”
Mahogany, anigre and sapele	Unlimited	3/8” x 1/8”
Red & white oak	Unlimited	1/2” x 1/2”
Hickory	Doesn’t exist	Doesn’t exist
Walnut and cherry	Unlimited	1/2” x 1/2”

Grade D – Essentially the same as C grade face, with the exception of allowing for some rough cut veneer and allowing for more knotholes, whether sound or repaired. There is no actual limit stated, leaving it is up to the manufacturer and the buyer what is considered acceptable.

Back Side

The back of the sheets is graded separately from the front side, with a numbering system used in place of the letters to keep things clear. The numbers 1 through 4 are used, with grade 1 being the best. All of these grades allow for sapwood, discoloration, stains and mineral streaks.

Grade 1 – Can contain as many as 16 sound tight knots, not exceeding 3/8” in diameter, but may not contain any repaired knots. Mineral streaks are allowed.

Grade 2 – The same number of sound tight knots are allowed, but their size cannot exceed 3/4” in diameter. Repaired knots are allowed, as well as rough cut veneer and unlimited mineral streaks. There should not be any open defects.

Grade 3 – There is no limit to the number of sound tight knots, up to ½”; however, there may not be more than 16 which are from 1/2” to 1-1/2” in diameter.

Grade 4 – Generally referred to as a “reject back” and only used in places where it is not visible. There is no limit to the number of sound tight knots or repaired knots. You are most likely to encounter Grade 4 backs on 1/4” plywood.