Paul Perry and Terry Fitchett jumped into action after spotting the pensioner falling into the Basingstoke Canal as temperatures plummeted on Tuesday afternoon.
Terry was working on the roof of a house opposite the canal in Glen Road, Fleet, when he heard a loud splash and saw the man in the water.
He called down to 18-year-old Paul, who immediately ran to the canal and jumped in.
“I just didn’t think about what I was doing — I just went ahead and did it,” said Paul.
“The water was cold and it went up to my neck while I was on tip-toes.
“It had been raining hard just before the accident so the man probably slipped and fell in.
“He was in the middle of the canal with his face down and actually went under the water at one stage.
“I got to him and I lifted him up while I was walking backwards.
“I got to the side and Terry helped pull him up on to the bank.”
Terry, 36, said: “We tried to get his mouth open but it was shut tight.
“We then pushed on his chest and his mouth opened and some water came out.
“We put him on his side in the recovery position and then some more people came down and helped out.
“He stopped breathing again so we started doing more chest compressions and luckily the paramedics came and took over.”
The heroes work for Church Crookham-based TM Roofing and Building Contractors.
Their boss Trevor Martin said: “The lads have done the company and themselves proud. If they hadn’t got him out of the water he probably wouldn’t be alive today.
“What they did doesn’t surprise me though because they always work very well as a team. I’m proud to have them on board and I’m as pleased as punch for them.
“Builders are always getting a bad press, with all sorts of horror stories, but this goes to show that we are decent chaps.
“I know the canal is not very deep but this was an elderly gentleman and the water was freezing cold.
“Everyone involved in the rescue was brilliant. One man in the house next to where we are working offered Paul some dry clothes to wear — everyone pulled together and it was a real team effort.
“Paul is only a youngster but over the time he has been working for me he has turned into a smashing apprentice.
“I brought them in a crate of beer each the morning after and they said ‘what’s that for?’ — I said for being heroes.
“They just said anyone would have done the same, but I’m not so sure.”
Surrey Ambulance Service spokesman Jon Lane said: “The elderly man had swallowed a lot of water and was not far from drowning. He was taken to Frimley Park Hospital in a critical condition.
“The canal was very mucky and freezing cold and we are very proud of the builders for what they did.
“Special thanks go to them on behalf of Surrey Ambulance Service.”