Hi 2 years ago I had a retaining wall built at the front of my property, I have recently noticed a small thin crack running from the top of the wall following the mortar line for 2 brick widths then through the middle of two facing bricks. There are no other cracks in the wall, no damage to the wall there is no weight at the top of the wall where the crack starts and all the weepers are free of debris and working well. This wall forms a boundry between my property and a pavement. Not being very experianced in DIY I would apreciate any advice you think relevant.
Many Thanks
Steven