Abstract
Staining on external walls is one of the important problems from the point of view of marring the appearance of building. This paper aimes to obtain the basic knowledge of stains those occur from the flowing rain and to clear the influence of flowing suspension on tristimulus values of porous cement material surfaces. The conclusions are as follows ; The tristimulus values decrease with the increace of total quantity of the flowing suspension and approach to stationaly values. Changes of the tristimulus values are explained by a material coefficient and total quantity, dencitv. flux of the flowing suspension and the experimental results were in fairly good agreement with calculations.
