I stayed away fro any lumber over 3/4 of an inch. The expansion and contraction from heating and cooling of wood under 1 inch is the same as the epoxy. If you have timbers larger you may create possibilities of delamination. Any defects in a single piece of lumber is lessened by having several pieces laminated togeather. If you have just 1 defect in 1, 2X10 you could loose the whole timber.