According to DIN 18195-9 / DIN 18533-1, single-layer, loosely laid sealing sheets must be edged with permanently compatible supplements arranged on both sides. The tightness of fixed and loose flange constructions is only guaranteed if the thickness and the elasticity of the sealing membrane or the allowances is so large that it presses tightly against the substrate. When laying waterproofing membranes, in addition to the requirements of the standard (laying guidelines), the information provided by the membrane manufacturer must also be observed!

A) Use with very thin or hard geomembranes - Curaflex® 1775

With geomembranes made of very thin and / or very hard materials, there is often not sufficient pressure on the substrate. When using such waterproofing membranes, the standard provides for the use of allowances. DOYMA allowances are made of material-compatible elastomer EPDM and already have the appropriate bolt holes in the fixed flange and are therefore ready for installation. These matching allowances are not part of the standard scope of delivery.

B) Use with other waterproofing membranes

With geomembranes e.g. from bitumen or bitumen rubber there is usually even pressure on the substrate. In such cases there are no problems with tightness. Therefore, no allowances are required.


Curaflex® packings for thin and hard foils (1775):  Curaflex® allowances consist of 2 pieces of 3 mm thick EPDM blanks that are matched to the dimensions and bolt circles of the selected fixed / loose flange construction.