If a new, or wider, opening is to be formed, the remaining wall above the new opening will need to be supported, typically by installing one, or more usually, two new, properly designed, beams.
os yw’r ffens, y wal neu’r gât dros 1 metr o uchder ac wrth ymyl priffordd a ddefnyddir gan gerbydau (neu lwybr troed priffordd o’r fath); neu os yw dros 2 fetr o uchder mewn mannau eraill; neu