Some of the finest features of this period are the magnificent timber roofs ; hammerbeam roofs , such as those of Westminster Hall ( 1395 ) , and Christ Church Hall , Oxford , appeared for the first time . Some of the finest features of this period are the magnificent timber roofs ; hammerbeam roofs , such as those of Westminster Hall ( 1395 ) , Christ Church Hall , Oxford , and Crosby Hall , appeared for the first time .