An experimental data about the effect of long-term natural aging without load and aging of samples under tensile stress on the mechanical characteristics of low density polyethylene (LDPE) under uniaxial tension are presented. A comparison between the mechanical characteristics of unstabilized and stabilized by a 2 % soot content of polyethylene is made. The influence of long-term impact of ash on the strength of polyethylene is estimated. The dependences for calculating the resource of the impervious elements of structures are given. It is shown that low density polyethylene composites have higher mechanical characteristics than the main component. It is substantiated that polyvinylchloride, manufactured using thirty percent of technological and forty percent of operational PVC waste, has high and stable mechanical characteristics. The influence of long-term aging and the effect of environments have been estimated. It is determined that the glass-filled polyamide and polyamide containing from twenty five to seventy percent of the technological waste has sufficient structural strength.