This Technical Report provides general guidance to the users of EN 15804 and those preparing complementary Product Category Rules (c-PCR's) by: – stating general principles for the use of EN 15804 by CEN Technical Committees for construction products (Product TC's) in order to ensure consistency among the complementary PCR produced by Product TC's; – addressing the questions raised by Product TC's, manufacturers or their sub-contractors who provide LCA studies underlying an Environmental Product Declaration (EPD) and by EPD programme operators who include c-PCR of specific subcategories in their PCR registry.