You may wish to use an installer who is registered with the relevant competent person scheme for replacement of roof coverings on pitched and flat roofs
Efallai y byddwch am ddefnyddio gosodwr sydd wedi'i gofrestru gyda'r cynllun person cymwys perthnasol ar gyfer adnewyddu gorchuddion toeau ar do ar oleddf a fflat.