The bays were built, plumb and level and set out to the correct angle. Movement out of this range is indicative of structural movement which needs to be considered and if necessary addressed.
These bays were often built with lesser foundations and thus are more prone to movement. These bays create an opening in the main front elevation brickwork and there will be a Bressummer Beam supporting the brickwork above. In the external wall of the bay there will be wall plates which will be supporting the ends of joists in the bay and the front elevation. All these timbers can be subject to rot if the brickwork is not correctly maintained.
Agreed Party Wall Surveyor serving Thanet
Party Wall Third Surveyor serving England and Wales