5-ply red oak lumber


Senior Team Emeritus
Premium Member
Had an experience last week with some 3/4" five ply red oak lumber. Found that it split near the end grain easily and smelled like Shi%t while cutting it. (Smells bad!!!)

Lumber didn’t seem that dry and was only a few months old. What’s the cause of the smell and the towards the edges of the lumber splitting more easily when screwing into the end grain?

How is the construction of this plywood different than say a CDX grade of 3/4" five ply which became these noticeable differences?


CB Mods
Premium Member
That's what I call vomit wood, though typically it's luan that smells like vomit when it gets bad.
Usually the sypmtoms you described occur when the engineered wood product has been exposed to a high humidity for too long. The splitting at the end grain is typical when water has seeped in and weaked layers of wood closest to the resin binder. Usually the resin itself is impervious to water but the wood nearest the resin get wet degrades and loosens. This also can create the bad smell you described, the wood has literally been being digested by bacteria, mold, little cavorting beasties.
The main difference between a red oak 5 ply and a typical fir 5 ply cdx s the quality of the veneers. A 5 ply red oak would typically be a AC or BC quality lumber product. The qualities of plywood in a 5 ply product would be. AC <rare in a 5ply> BC, CD, Shop Sanded,CDX and Mill Cert. <certified> and it all has to do with the number and size of voids in the individual veneers and wether or not anything has been done to those veneers to treat them. AC would have an A grade side and a C grade side the veneers making up the interior of the product would typically have no more than 4 voids per sheet and they would be neccessaryly small and or they would be filled prior to adhesion and pressing. When finished the A quality side, typically the oak, cherry, birch, or other pretty wood, would be lightly sanded to give a nice ready for finishing finish. The C side may have a few "footballs" on it but generally free of major voids or imperfections. The grades of plywood go downhill quickly after that. CDX can have major voids in the middle of it and is typically used for it's shear strength for sheathing the outside of stick framed homes etc. The X in CDX stands for Exterior, however, do not confuse that with Marine Grade which is able to stand up to submersion and direct exposure to water.

How's that ?

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