Catalyzes the addition of glucose to the C-2 hydroxy group of the glycerol units in teichoic acid. 4-O-{[(2R)-1-glycerylphospho](n)-(2R)-1-glycerylphospho}-N-acetyl-beta-D-mannosaminyl-(1->4)-N-acetyl-alpha-D-glucosaminyl undecaprenyl diphosphate + n UDP-alpha-D-glucose = 4-O-{[(2R)-2-alpha-D-glucosyl-1-glycerylphospho](n)-(2R)-1-glycerylphospho}-N-acetyl-beta-D-mannosaminyl-(1->4)-N-acetyl-alpha-D-glucosaminyl undecaprenyl diphosphate + n H(+) + n UDP kcat is 17 sec(-1). Cell wall biogenesis; poly(glycerol phosphate) teichoic acid biosynthesis. Positively regulated by WalR. Mainly expressed during exponential growth and rapidly shut off as cells enter the stationary phase. Not essential. No glucose groups on the glycerol residues of teichoic acid in cell walls. Belongs to the glycosyltransferase group 1 family. Glycosyltransferase 4 subfamily.