Add layer on all floors with dynamo

hi … i want to add 1 layer on all floors using dynamo and this layer
( for example this layer material : gyps ) and this layer i want it on the floor layers, cause floor structure setup take the level as reference . so i want to add this extra layer using dynamo to let it on the placement (level) … i know i can use top offset or base offset … but if there is anyway to add layer using dynamo !!
thanks in advanced