If it is burned up, he will suffer loss. He himself will be saved, but only as if through the flames.
15. If any man’s work shall be burned. It is as though he had said: Let no man flatter himself on the ground that, in the opinion of men, he is reckoned among the most eminent master-builders, for as soon as the day breaks in, his whole work must go utterly to nothing, if it is not approved of by the Lord.
Here the apostle informs us what foundation he had laid at the bottom of all his labours among them - even Jesus Christ, the chief corner-stone, Eph 2:20. Upon this foundation all the faithful ministers of Christ build. Upon this rock all the Christians found their hopes. Those that build their hopes of heaven on any other foundation build upon the sand.
Commenting on 1 Corinthians 3:11-15
If any man's work shall be burnt,.... If any minister's doctrine he has preached shall be destroyed and disappear, shall be disapproved of, and rejected by the churches, not being able, to bear the light and heat of the fire of God's word: he shall suffer loss; of all his labour and pains he has been at, in collecting together such trifling, useless, and inconsistent...