A client contacted SERL to evaluate a chimney stack that had been modified during a past renovation by a previous owner, which the Surveyor suspected might not adhere to Building Regulations.
Structural Engineers Reports Limited (SERL Pole) was approached by a prospective buyer who was seeking a reputable, independent, and experienced engineering firm specialising in Structural Engineers’ Reports in the South London Surrey area.
In response to the client’s requirements our qualified Chartered Structural Engineer recommended a Specific Structural Inspection report.
SERL offers two types of structural engineers reports:
1) A localised, specific, and limited Specific Inspection Report (SSI), also known as a Structural Engineer’s Defect Report.
2) A broader General Structural Inspection Report (GSI), or Structural Engineers General Movement Report focusing solely on issues of cracking and movement.
We provided a bespoke Structural Engineers Report for the property in Croydon, which was a variation on our SSI report.
The current owner had occupied the house for about 10 years, with the alteration predating their ownership, indicating significant age. The chimney brickwork was in reasonable condition with some bonding to the party wall. It was assumed the neighbouring chimney breast and stack remained intact.
Our findings revealed that the chimney breast had been removed to enlarge the rear bedroom.
However, the loft space above the chimney breast remained and was simply resting on the slender and modest ceiling joists. These beams were also nominally built into the party wall, providing some improvement. Additionally, the timber roof purlin rested on the chimney stack, increasing the weight load beyond normal levels.
The existing support arrangements did not comply with Building Regulations, either currently or at the time of the initial modifications, likely over 20 years ago.
The chimney breast has stayed in place primarily due to the bonding or toothing of bricks between the party wall and the stack, rather than the ineffective steel beams resting on ceiling joists which were not strong enough.
Fortunately, there had been no recent major building works, which could cause vibrations, has prevented potential safety issues with the chimney breast. However, catastrophic failure could have resulted in the stack collapsing into the bedroom below. We recommended reinforcing the chimney stack with RSJ beam supports in the loft at a cost of approximately £5,000. Provided the work is completed soon, we deemed the situation manageable.
The main learning points include the necessity for owners to obtain Building Regulations Approval from the Local Authority for any structural alterations, rather than confusing it with Planning Permission, Permitted Development rights, or Party Wall approval. Current Building Regulations submissions require structural calculations from a Chartered Structural Engineer, as local authorities can no longer approve builders’ proposals lacking calculations following the Building Safety Act 2022.