More seasonal weather and a soft comparison base are expected to boost second-quarter sales and margins at DIY retailer Kingfisher, according to Jefferies which reiterated its 'buy' rating and 400p target price for the stock.Jefferies expects sales growth of around 6.0% in the second quarter. Comparatives with last year are "usefully weak" as gross margins in Britain suffered from poor weather and a mixed execution of clearance ahead of category relaunches last year.More normal trading conditions are expected to drive a 3.1% rebound in like-for-like sales at B&Q and an 80 basis-point recovery in gross margins."Crucially, downside pressures in France seem to be reducing at a time when the UK property market is rebounding strongly, well ahead of government measures set to provide further support to housing transactions."The update on second-quarter trading is due to release on July 24th, but for now, Jefferies said Kingfisher's valuation remains "undemanding in the context of the group's recovery/releverage prospects".The stock was up 0.29% at 379.6p by 10:00 on Monday.BC