With the help of the “Plattenschlot” method which is intended to be included into the German standard DIN 4102, comparative fire tests on wood and wood-base materials were carried out. The materials were partly unprotected and partly protected by fireretardant preservatives. The temperature of the air of combustion, the temperature of the shaft wall as well as the loss of weight were measured. The results, average values of three equal tests, were represented in diagrams and discussed. The curves resulting from graphic differentiation were very instructive for the speed of temperature changes and for the speed of the loss of weight. For the evaluation of the behaviour of the examined board-materials also the dimensionless combustion measure can be brought up. The total results were additionally represented in 2 tables. For the new edition of DIN 4102 it was lately being considered to acknowledge the property “flame-retardant” only if the maximum temperature of the air of combustion does not exceed 250°C and the loss of weight does not rise beyond 30%. Though two thirds of the materials examined failed, the test procedure is, according to the authors' opinion, not too strict. With respect to safety, the maximum temperature of the air of combustion has to be coupled with the maximum loss of weight. Considering the fact that within the region of 220 to 280°C the pyrolysis of wood begins to become exothermical, it should even be investigated whether this maximum temperature permissible should not be reduced. Tests have shown that with sufficient effectiveness of the fire-retardant preservatives this condition can, without difficulties, be complied with. Also spruce of 20 mm in thickness, which untreated is highly endangered, as well as 12 mm plywood having been painted with intumescent preservatives became acceptably “flame-retardant”. It is important to concert gluing technique and fire protection.