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Grading - Silva Select No.4 Clear Western Red Cedar

Species:                                  Western Red Cedar
Grade:                                     No.4 Clear
Grading body:                        Pacific Lumber Inspection Bureau (PLIB)
Reference:                              Paragraph 401-a


The purpose of this document is to provide a detailed, factual and accurate description of the material along with the officially published grade description where applicable.

It goes without saying that reading this description is no substitute for seeing the actual material.  We are always happy to send out hand samples, but they have very limited use in determining the overall quality - it is impossible to cram every feature and characteristic that you might encounter in a delivery of timber on a single 6” sample.  For this reason we encourage you to visit our premises and take a closer at the product before you buy. 


What is a timber grade?

The grading of timber can be defined as the sorting of wood sawn from a log into different qualities relating to classifications for appearance, end use or strength. The practice is essential to maintain consistency and to ensure reliability from order to order.

A timber grade is simply a minimum standard describing the extent and limitations of the characteristics permitted in a piece of timber depending on its end use.

Grading is explained in further detail in our document – ‘The Grading of Timber’

Silva Select ‘No. 4 Clear’ Grade

This particular product is produced from a sawn Western Red Cedar clear grade known as ‘No. 4 Clear’.  It is one of two grades - the other being No. ‘2 Clear and Better’ - of sawn clear Western Red Cedar which are classified in accordance with the R-List Export Grading Rule Book published by the Pacific Lumber Export Bureau. 

The actual grading rules as they appear in the aforementioned publication are set out below, however you will find probably find our own description to be more useful and a more accurate representation of our actual product.  This is because the grading rules describe the minimum standards for the grade.

The first thing to highlight about our ‘Silva Select No. 4 Clear’ product is that it far exceeds the grading rules set out for ‘No. 4 Clear’.  Usually with this grade you should expect a certain amount of trimming and wastage; however the producer of the sawn lumber has identified a demand for a product that is less expensive than ‘No. 2 Clear & Better’ but yields less wastage than standard ‘No. 4 Clear’. 

In our opinion this has been achieved with Silva Select No. 4 Clear.  We call it Silva Select because it’s a cut above the standard grade and we are the only company importing this product into the UK.  A number of our customers have expressed surprise at the quality, especially after reading the grade description which makes it sound far worse quality than it actually is. 



Many of the boards you will receive would classify as the more expensive ‘No.2 Clear & Better’ grade with many boards having no knots at all.  On those that do, the knots tend to be very small, sound and tight.  You may encounter the odd small knot hole and loose knot, but on the pack of 105 lengths of 2.44m Channel cladding featured in our video we found only four and they were all quite small so easily filled, cut out or even left in as they are. 

The grade actually permits 4 x 25mm knots per 200 x 3660mm sawn board.  This means that for the equivalent surface area of the pack we examined in the video, approximately 200 knots with a 25mm diameter would be permitted within the grading rules.  We found approximately 18 knots in the entire pack and virtually all were less than 10mm.


You may encounter the odd small split on the edge and ends, which can either be trimmed out or glued. 


In this grade you will see more boards with wide flat grain than you would in No. 2 Clear & Better – we found a handful. You may find the odd patch of minor surface damage caused during the handling process.  In most cases this can simply be sanded out.  We found three such patches in our pack. 

Damaged boards

In this pack we found three damaged boards that our pickers would typically remove before sending out and three more with minor damage that would either not be visible when installed (dings on tongues) or easily trimmed off the ends.

Colour variation

As with any natural wood product you should expect colour variation both between boards and within individual boards.


This particular pack was randomly selected and we know it to be representative of Silva Select No. 4 Clear.  The quality of raw material that we receive from our supplier is consistent from one shipment to the next, so we are confident that the material you receive will be of a quality similar to the material described above and shown in the video.  That said, please bear in mind that the next pack we could have chosen may have had more imperfections or it may have had fewer imperfections.

 You are likely to generate some off cuts when using this product, but by planning your cuts prior to installing this will be minimal.

In summary Silva Select No. 4 Clear is a very acceptable product that displays some minor imperfections but in general is of a high standard and is suitable for all types of residential and commercial buildings. 

As they are available in the same profiles, you may wish to consider ordering a percentage of Silva Select No.4 Clear with your No.2 Clear & Better grade order and use the less attractive pieces on the least prominent areas of the project for cost savings 

Click here to view the official grading rules for Western Red Cedar No.4 Clear 

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