In this study, sandwich panels made from oil palm lumber, sengon, and gmelina wood were impregnated with a boron-alum solution to improve their water andtermite resistance. Waterresistance testing was evaluated using a thickness swelling test following the method in SNI03-2105. The sandwich panelwasalso tested for its durability against dry wood termites,according to SNI 01-7207. Theweight loss, mortality,and attack degree were used as theparametersfor evaluating termite durability. The results showedthat the treatment with aboron-alum solution can increase the stability, water resistance, and weight loss properties up to 73%, 41%, and 100%, respectively. The best properties of the sandwich panel were obtained by the sengon-isocyanate panel with 8% boric acid-borax and 5% alum treatment which has thickness swelling of 2.37%, water absorptionof 49.04%, weight loss of 0.0124%, termite mortality of100%,and attack degree of 0.