Following the sentencing Trevor Reeves said losing the store has been like a bereavement.
Mr Reeves, 56, said: "On August 8, Gordon Thompson in front of the world, burnt down a furniture store in Croydon. That was our store and the sentence will not bring it back.
"My father has built that store up, that store was his baby. I've lived there as a child, played there as a child.
"I lived there as an adult and worked there for most of my adult life and when you lose something like that it's like a bereavement.
"The justice system now has to do its job. It has now got 11-and-a-half years to rehabilitate a man who is a repeat offender and to stop him doing it again."
Speaking outside the court, his father Maurice, 81, said he accepted the apology Thompson had offered.
He said: "I think [the apology] is accepted by the family, it's accepted by me and good for him.
"I don't know how such a man could do so much harm to so many people, but we have to fight back and that's what we are doing. That's the typical Reeves family."
Mike Fisher, leader of Croydon Council, said: "What we witnessed in Croydon last year must never be allowed to happen again.
"Gordon Thompson shamed his home town when he decided to set fire to the Reeves Furniture store and I am very pleased that he will now spend a long time in prison paying for that terrible crime."
Labour Leader Councillor Tony Newman said: “It is a lengthy sentence that sends a very strong message that criminal behaviour cannot and will not be tolerated.
“I heard Maurice Reeves on the radio earlier and he brought up his concerns about not enough being done about London Road, which I thought was very significant.
“The jail sentence is only part of it, for everyone to move on we need to see that site [House of Reeves] and London Road and other parts of Croydon have significant investment in them.
“The council are just using the riot money to pay for a few hanging baskets, it is an insult for all concerned and they should listen to Mr Reeves.”
Superintendent Simon Messinger of Croydon police said outside the court: "Today Mr Thompson has been sentenced to 11.5 years in custody a considerable time for him to consider the outcome of his reckless actions and the emotional, financial, physical disruption this has caused, not just only the Reeves family but many local residents in Croydon.
CPS London deputy chief crown prosecutor Jenny Hopkins said: "Gordon Thompson's callous actions recklessly endangered the lives of many innocent people, not least the firefighters who bravely extinguished the blaze.
"Few will forget the terrifying ordeal of Monika Konczyk, whose flat overlooked the store. She had to throw herself from her blazing flat into the arms of those same firefighters after she had become trapped by the flames.
"A much loved and memorable local building was razed to the ground and the efforts of five generations of hard-working members of the Reeves family to build up their family business were destroyed.
"Members of the public both in Croydon and elsewhere, were shocked at the television footage which showed the extent of the damage caused by Thompson's actions.
"When faced with the strength of the case against him, Thompson pleaded guilty, which meant many witnesses did not have to relive distressing memories about that happened that night."