The body of Liam Aitchison, 16, from South Uist, was found in a derelict former RAF accommodation block at Steinish near Stornoway Airport in November 2011 after he was beaten and stabbed.
Highlands and Island Airports were approached by the local community to demolish the single storey structure. It is to be pulled down in October.
Councillor Angus McCormack welcomed the news saying it had been a constant reminder to local people of the "terrible tragedy."
Liam's killers Johnathan MacKinnon and Stefan Millar are both serving life sentences.