The Judge, Mr Philip Richards, said the fire was a "very irresponsible act" with "consequences that were devastating". He acknowledged that Mr Goulding has considerable learning difficulties which is why he took so long to accept responsibility.
Mr Goulding has been remanded in custody and will be sentenced tomorrow at 2pm at Newport Crown Court.
More top news
Most places will see a dry, bright day with patchy cloud but also some warm sunny spells, and it'll be less breezy than on Friday.
Members of the RMT union are walking out for three days from today in a row over new trains causing disruption to bank holiday services.
The Bank Holiday is here! Which is usually a recipe for wet weather! Yes, we will get our fair share. But it's not all doom and gloom!