​​​​You will need planning permission if you want to alter a building, piece of land or a permanent structure (such as a wall) and you need to carry out building work to do it.
​​​Bydd angen caniatâd cynllunio arnoch os ydych am addasu adeilad, darn o dir neu adeiledd parhaol (fel wal) a bod angen i chi wneud gwaith adeiladu i gyflawni hyn.