Multi Treatments Limited
Cavity Wall Tie Corrosion - The Problem
Cavity walls incorporating metal ties have been in use since the beginning of the nineteenth century but it was the 1930's building boom that produced large numbers of cavity construction dwellings. From 1945 cavity wall construction became the normal for houses and many other buildings.
The early metal ties produced mainly from wrought or cast iron performed satisfactorily but in more recent years mild steel ties have been used.
The estimated life of these mild steel ties is appreciably less than the 60 year life expected. The 1945 standard was relaxed in 1964 and 1978 but in 1981, when the extent of the problem was registered, the British Standard was amended to triple the zinc coating thickness on a wire tie.
Wall tie failures reported to the Building Research Establishment (BRE) include inferior coatings of bitumen, insufficient zinc galvanizing on mild steel, aggressive mortars (particularly black ash), exposure to marine climates and permeable mortars such as lime that permits rapid carbonation.
Cavity Wall Tie Corrosion - The Solution
1. Spiro Remedial Ties
Spiro Remedial Ties are manufactured from austenitic Stainless Steel Type 304 to BS1449. The ties are manufactured from Stainless Steel strip which has been slit to give the required sectional profile, and twisted to form a continuous spiral of any length. The section is approximately 7.6mm diameter and 2mm thick.
Before installing Spiro Remedial Ties, the condition of the inner leaf must be established. The correct length of Spiro should be established, taking into consideration the maximum and minimum cavity width.
Penetration into the inner leaf can be determined by the amount of tie left out from the Spiro tie tool.
Pull out strength figures for the Spiro Ties are in the region of 2Kn - 2.5Kn depending on the type of masonry in place.
2. PAM Double Mechanical Wall Tie
Unique design concept - a Pre-Torqued Full Radial Anchor Expansion Fix tie of the highest quality.
PAM Double Mechanical Wall Tie is the reliable Double Mechanical Precision Pre-Torqued Tie that sets new standards in replacement wall ties. Its unique special coated black stainless steel precision limited torque nut combined with the precision modified stainless steel bar provides a fixing system which permits:
- 1. Rapid continuous fixing to both inner and outer leafs in under ten seconds
- 2. Ensures inner leaf fixes to pre-torqued level before outer leaf engages
- 3. Pre-torque setting reliably produces pull out figures in excess of over 2.5 kilo newtons
- 4. Can be easily fitted using a power drill or a single manual tool for fast, efficient low cost installation
Contact us for friendly advice, estimates and Inspections.
Cavity Wall Tie Corrosion - The Problem
Cavity walls incorporating metal ties have been in use since the beginning of the nineteenth century but it was the 1930's building boom that produced large numbers of cavity construction dwellings. From 1945 cavity wall construction became the normal for houses and many other buildings.
The early metal ties produced mainly from wrought or cast iron performed satisfactorily but in more recent years mild steel ties have been used.
The estimated life of these mild steel ties is appreciably less than the 60 year life expected. The 1945 standard was relaxed in 1964 and 1978 but in 1981, when the extent of the problem was registered, the British Standard was amended to triple the zinc coating thickness on a wire tie.
Wall tie failures reported to the Building Research Establishment (BRE) include inferior coatings of bitumen, insufficient zinc galvanizing on mild steel, aggressive mortars (particularly black ash), exposure to marine climates and permeable mortars such as lime that permits rapid carbonation.
Cavity Wall Tie Corrosion - The Solution
1. Spiro Remedial Ties
Spiro Remedial Ties are manufactured from austenitic Stainless Steel Type 304 to BS1449. The ties are manufactured from Stainless Steel strip which has been slit to give the required sectional profile, and twisted to form a continuous spiral of any length. The section is approximately 7.6mm diameter and 2mm thick.
Before installing Spiro Remedial Ties, the condition of the inner leaf must be established. The correct length of Spiro should be established, taking into consideration the maximum and minimum cavity width.
Penetration into the inner leaf can be determined by the amount of tie left out from the Spiro tie tool.
Pull out strength figures for the Spiro Ties are in the region of 2Kn - 2.5Kn depending on the type of masonry in place.
2. PAM Double Mechanical Wall Tie
Unique design concept - a Pre-Torqued Full Radial Anchor Expansion Fix tie of the highest quality.
PAM Double Mechanical Wall Tie is the reliable Double Mechanical Precision Pre-Torqued Tie that sets new standards in replacement wall ties. Its unique special coated black stainless steel precision limited torque nut combined with the precision modified stainless steel bar provides a fixing system which permits:
- 1. Rapid continuous fixing to both inner and outer leafs in under ten seconds
- 2. Ensures inner leaf fixes to pre-torqued level before outer leaf engages
- 3. Pre-torque setting reliably produces pull out figures in excess of over 2.5 kilo newtons
- 4. Can be easily fitted using a power drill or a single manual tool for fast, efficient low cost installation
Contact us for friendly advice, estimates and Inspections.
