No one was hurt in the overnight blaze, believed to have been started by a faulty fridge, which forced the abandonment of the two-storey temporary suite being used for this weekend's grand prix at Sepang.
But equipment belonging to ex-world champion Raikkonen and Grosjean was being hurriedly cleaned for Saturday's qualifying session after being coated with soot. Raikkonen's spare helmet "perished in the blaze", a statement said.
The hiccup adds to a bumpy week so far for Lotus, whose main driver Raikkonen has been penalised five grid places for Sunday's race after fitting a new gearbox.
Raikkonen, the 2007 champion who spent the last two years in rallying, started 18th on the grid at last weekend's season-opener in Australia, although he fought through the field to finish the race seventh.
"The team asks for forgiveness for certain personnel who have entered the fire-damaged facility as they will be rather smoke-fragranced today," a Lotus statement said.
Fire hits Lotus at Malaysian GP
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