He knocked on the victim’s door last Thursday, January 13, and stated that he had fixed the guttering that was hanging off and he owed him £20 saying “small job, small pay”.
The victim took his word for it and gave him £20 cash.
The suspect told him to sit back in his chair and while the victim was not looking, he picked up his wallet, removed a large amount of cash, and left the property.
It happened at around 1.30pm.
The male suspect is described as a white male, medium height, dark clothing, with a "sharp nose", age mid 40s and with a local accent.
The police said: "Please remind relatives, neighbours and friends about this type of scam as bogus workmen prey on the vulnerable and try to obtain cash, through deception, for work that is not necessary.
"Please remember - you don’t have to let anyone into your home.
"Always check the ID of the person at the door and don't be afraid to make checks via a phone call with the company/organisation that the doorstep caller is claiming to be from.
"Never ring a phone number provided by that of the doorstep caller, always obtain the correct number for yourself to make sure you are definitely contacting who you believe to be."