This petition was rejected

The Government e-Petitions Team gave the following reason:

We can't accept your petition because the UK Government and Parliament don't make decisions about whether a building needs to be demolished after a fire.

The fire at the Glasgow School of Art was discussed in the House of Commons on June 19. The UK Government Minister said:

"The UK Government previously gave £10 million to rebuild the school after the last fire, and we stand ready to help again. There was never a question about the need to rebuild and restore the building when tragedy struck four years ago. The situation is far worse after the weekend’s fire, but I hope we can start with that aim in mind."

You can read what was said here:

hansard.parliament.uk/commons/2018-06-19/debates/43B5B409-ED63-4E1C-AAB2-A7989DF93DAE/GlasgowSchoolOfArt

You could a new petition about something the UK Government and Parliament are responsible for. For example, you could start a new petition asking the UK Government and Parliament to meet the costs of restoring the Glasgow School of Art.