(Sharecast News) - Home Construction and Auto & Parts stocks are among the weakest areas of the market on Tuesday, with the former getting slammed after a weak reading on activity in the sector, against a backdrop of ongoing negative news-flow around the state of the Brexit negotiations, and the former weighed down by global trade uncertainty.Symptomatic perhaps of the construction sector's plight, earlier in the session homebuilder Redrow's boss, Steve Morgan, called for "clarity" on Brexit and 'Help to Buy', saying that if provided with such clarity, then the company would deliver.Indeed, some analysts, such as those at Berenberg, had over the past few weeks sounded a relatively upbeat note on the sector, arguing that investors were likely being too negative on the shares of some of the sector's constituents.Despite the better-than-expected results from Redrow, the shares were trading lower, although the worst punishment was being meted out to Berkeley Group ahead of a trading update due the next day.Weighing on sentiment, IHS Markit's construction sector Purchasing Managers' Index for August had printed at 52.9, which was down from July's reading of 55.8.To take note of, according to IHS, the house building sub-sector saw the weakest levels of activity.That prompted Duncan Brock, Group Director at the Chartered Institute of Procurement & Supply, to say: "The sector is hovering too close for comfort to the no change mark which makes it a contender for more disappointment next month. Though the path to Brexit is paved with good intentions, without significant progress the sector will soon be building castles in the air rather than on solid ground."Top performing sectors so far todayBanks 4,073.63 +0.68%Electricity 7,646.38 +0.28%Beverages 21,852.79 +0.14%Tobacco 41,951.58 +0.12%Oil Equipment, Services & Distribution 15,214.11 +0.02%Bottom performing sectors so far todayAutomobiles & Parts 11,290.85 -3.72%Industrial Metals & Mining 4,423.01 -2.33%Household Goods & Home Construction 16,549.85 -2.08%Mining 16,606.23 -1.88%Software & Computer Services 1,809.97 -1.86%