 St Edern 's is built in the Perpendicular style using local stone , with blocks of cut sandstone as the external face . The roof is made from slate with stone copings and has a bellcote at the west end , with one bell ( dating probably from the 17th century ) . There is one external buttress to the south @-@ east of the nave to help support the weight of the building , and there are crosses on the roof of the porch and at the east end of the nave and chancel roofs . 
