The objective of this study was to investigate the effects of zinc chloride (ZnCl2) and borax (Na2B4O7.5H(2)O) on combustion properties of laminated veneer lumbers (LVLs) with two, three and four-layered, produced from white oak (Quercus alba) and chestnut (Cestanea sativa Mill.) woods. Veneers obtained for LVL were impregnated according to ASTM-D 1413. Veneers applied vacuum method were dried and bonded with poly(vinyl) acetate (PVAc) and D-VTKA polyurethane-based adhesives. The combustion test was performed according to the procedure defined in the ASTM-E 69 standard The results indicated that the highest weight loss of LVL (43.1 g) was observed in unprocessed weigh wood samples. The lowest O-2 consumption ratio was in borax-impregnated LVL samples with Desmodur-VTKA, with a ratio 20.4%. The highest CO ratio observed in LVL control samples was 2834.7 ppm, the highest temperature measured in borax-impregnated control LVL was 398.5 degrees C, the highest ash ratio was measured as 82.4%, however NOx and SOx emissions (oxides of nitrogen and sulfur) could not be measured, because heat did not go up to 1000 degrees C. As a result, borax was found to be an effective fire-retardant chemical in LVL. in conclusion, it can be recommended as a fire-retardant building material. (C) 2007 Elsevier B.V. All rights reserved.