Construction and materials stocks were performing well on Tuesday after the British Bankers' Association (BBA) revealed that mortgage approvals hit a 16-month high in May.Approvals for house purchases reached 36,102 last month, up from a revised 32,952 the month before, well ahead of the 33,200 consensus forecast and 11% higher year on year.The average approval value of a house also rose from £156,200 to £159,200 from April to May, above £152,000 in May last year.The BBA said in a release: "Assistance schemes for mortgage lending are also expected to help more first-time buyers and housing chains generally in due course."Ashtead, CRH, Galliford Try, Balfour Beatty and Barratt Developments were among the best performers this afternoon.Top performing sectors so far todayAutomobiles & Parts 6,831.83 +3.58%Technology Hardware & Equipment 953.62 +2.98%Construction & Materials 3,559.98 +2.62%Beverages 13,909.83 +2.54%Industrial Engineering 8,869.33 +2.51%Bottom performing sectors so far todayOil Equipment, Services & Distribution 21,354.34 -0.60%General Industrials 3,611.06 -0.56%Industrial Transportation 2,821.22 -0.55%Electricity 9,123.17 -0.36%Health Care Equipment & Services 4,121.70 -0.08%