Many of these could have an adverse impact on the building and its occupants if they are not properly thought out, planned and undertaken in accordance with the requirements of the legislation.
Gallai llawer o'r newidiadau gael effaith andwyol ar yr adeilad a'r sawl sy'n byw ynddo, os na chymerir camau priodol i ystyried, cynllunio a chyflawni'r newidiadau yn unol â gofynion y ddeddfwriaeth.