The blue-chip index added 0.9pc, with a sub-index of housebuilders hitting a record high.
The FTSE 250 gained 0.4pc, helped by a 7pc jump in Hochschild Mining after it reported 2019, results and targets for 2020.
Berkeley was the most notable gainer on the blue-chip index as it rose 3.2pc to an all-time high. Fellow housebuilders Barratt, Taylor Wimpey and Persimmon also rose between 1pc-1.5pc.
The sector is particularly sensitive to the domestic economy and updates on Britain's departure from the European Union, both of which have influenced consumer demand.
"The decisive general election result has brought the prospect of a final settlement of Brexit closer and unleashed pent-up demand in housing activity," HSBC analysts said.
Miners and oil stocks also boosted the FTSE 100. HSBC rebounded from a more than 6pc slide in the previous session when it reported lower profit and laid out plans for a strategic overhaul.
Among midcaps, hedge fund manager Man Group surged 7.2pc, which according to traders was due to a rating upgrade from Exane. In contrast, price comparison website Moneysupermarket.com dipped 2pc after saying its top boss would step down.
Both British benchmarks were coming off losses in the previous session due to a revenue warning from Apple that stoked fears over the economic fallout of the coronavirus outbreak.
The indexes hit their lowest in months in January, but have recovered along with global markets as world governments and central banks took measures to stem the economic impact of a health crisis in China.
"The markets are arguably in a transition period between focusing on daily new case and death toll figures to data that will show the economic impact of the coronavirus," Spreadex analyst Connor Campbell said.
Investors also look ahead to the release of UK's inflation data as well as minutes of the latest U.S. Federal Reserve meeting which could spur some moves.