BARCELONA, Feb 28 (Reuters) - Spain's Fluidra, the world's largest maker of swimming pool equipment, said it expects the pandemic to keep demand afloat this year after net profit more than doubled in 2021, pushing its shares up nearly 10% on Monday.

The Barcelona-based company benefited from COVID restrictions which encouraged people stuck at home to build swimming pools.

Profit reached 252.4 million euros ($282.3 million) last year, in line with Refinitiv estimates, which sent Fluidra's shares up 9.8% in mid-afternoon trade, while Madrid's blue-chip IBEX 35 index was down 1.5%.

"2021 was an extraordinary year," Chief Executive Bruce Brooks told Reuters, adding that its construction backlog remained strong, with some builders already booked for the whole year.

"It is a signal that pools are still very attractive in this hybrid environment of working from home and the office, that the cocooning effect is still there," he said.

The explosion in demand has long-lasting effects, as around three-quarters of Fluidra's business comes from maintenance.

Led by the North American market, sales grew 47% to 2.19 billion euros last year, above Fluidra's forecast.

It expects sales growth of 12%-17% this year and earnings per share to rise 10%-16% after doubling in 2021.

Brooks described the projections as "really strong" but warned of the impact of rising inflation and supply chain disruptions, which knocked 6% off sales last year, and are likely to have a bigger impact this year.

Fluidra raised prices in October and will do so again in March.

The company expects a minimal impact from Russia's invasion of Ukraine as the two countries together account for just 1% of sales. Fluidra has no operations in Ukraine but has some subsidiaries and employees in Russia though no manufacturing.

($1 = 0.8941 euros) (Reporting by Joan Faus, additional reporting by Inti Landauro; editing by Nathan Allen and Emelia Sithole-Matarise)