What causes veneer lamination to fail?

Question:

I applied wood backed veneer over a fiberglas column. The veneer is a three layer product consisting of the surface veneer which is about 11/1000s” thick, a paper layer, and a wood layer. The column is 15.5″ tall and about 30″ in diameter. I was sent 6 pieces of bookmatched veneer, each is 8′ x 36″. The application failed at one point. I am trying to determine the contributing factors for this failure.

The application required six vertical seams and three horizontal seams due to the size of the colum and size of the veneer sheets. The point of failure was wher the horizontal and vertical seams met at the center of the column’s height, approximately 8′ up or down its height, depending upon your perspective.

At this precise point, there was a “patch” of drywall and joint compound. This patch was an attempt to mate the lower column with the upper column to achieve the desired height of the column. I suspect this patch area was the contributing factor in the delamination failure although I am also wondering about surface prep, adhesive choice, method of applying the adhesive, environmental issues, proper grain direction of the wood backer, in relation to the face of the veneer.

I am looking for anyone who have experience with wrapping coluumns with veneer in hope of establishing a cause or causes of this failure. Any feedback would be very helpful.

Answer:

Based on your description of the whole assembly, the one thing that stands out is the drywall patch. Applying flexible veneer, or any veneer for that matter, over drywall isn’t recommended. We always suggest the use of Bondo or fiberglass body filler for patching or filling substrates. We fully agree with your assessment that this is the cause for the failure.

Oakwood Veneer Tech Support