A company with integrity
Broadoak Preservation Ltd in Manchester are qualified and experienced specialists in basement conversions, garage conversions, structural restraint and repairs and property refurbishments.
Cavity Wall Ties Installation
The absence of effective wall ties will ultimately
result in failure of a walls structural integrity and its probable collapse under high wind conditions.
CAUSES Inadequate protection – prior to the 1930s ties were not galvanised.
Substandard galvanising The British Standard for weight of galvanising was actually reduced between 1964 and 1981.
Chemical action for instance where corrosive black ash mortar has been used.
Location such as marine environments with driving rain and salt laden atmospheres.
The symptoms
- Horizontal cracking at regular intervals in external mortar joints
- Outward bulging of the wall
- The lifting of roof edges
- Internal cracks
There are two problems with corroding wall ties. The ties can corrode in the cavity and break such that the outer and inner leaves are no longer tied together. If this occurs, there is a distinct risk of the outer leaf collapsing, especially under high winds which cause suction on the face of the wall.
The Survey
To determine the spacing of the existing wall ties, the wall is inspected with the aid of a metal detector. To establish wall tie type cavity width and the extent of any corrosion, a visual inspection within the cavity is carried out with the aid of a boroscope and/or by the removal of the mortar bed and/or brick adjacent to a wall tie location.
We can then give recommendations for the correct remedial actions to be taken.