There are many different reasons for cracking in masonry structures. These problems can be overcome by using various combinations of Helical Systems masonry reinforcement products, which can also be utilised in new build situations.
The illustration shows a typical two storey semi-detached property of solid wall construction with a later cavity wall extension.
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HeliTie Bar
A reinforcing bar engineered from austenitic 304 or 316 stainless steel. The stainless steel is extruded giving the bar its unique shape and ensuring a uniform helical design. The method of extrusion produces fins, which are work hardened forcing them into tension, but leaves the core relatively soft and flexible. This design produces a helical bar which has remarkable qualities and whose tensile strength is more than double due to the extrusion process. Originally available in 4.5mm, 6mm, 8mm and 10mm diameters, the bar is also now available in 3mm diameter, especially well suited to thin joint technology.
HeliGrout
A range of very high performance, non-shrink, non-gassing, thixotropic, cement based grouts is available for use with the application of the HeliTie Bar.
HeliTie Fixings
A range of simple, no-nonsense, one-piece, high performance ties are available engineered in the same way as the reinforcing bar. These versatile ties come in different lengths and diameters with 'one point' or 'no points' to suit not only dry applications but also those requiring resin or grout. Their uniform helical shape ensures ease of installation and excellent holding power in a variety of building materials. These ties introduce no expansion pressure or extra stresses into the structure.
CemFix
A fixing used to secure and repair debonded masonry, stabilise solid or rubble filled walls and reconnect party walls to external walls. 8mm in diameter the 'no point' fixing is installed with HeliGrout into pre-drilled clearance holes, around 12-16mm in diameter.
BowFix
A fixing used to stabilise bowed walls. 8mm in diameter the 'one point' fixing is installed directly into the side or the end of floor joists, via a clearance hole in the outer masonry, around 12mm in diameter. The fixing is bonded into the masonry using HeliResin or HeliGrout.
HeliTie
A versatile 'no point' or 'one point' fixing used in a variety of applications from timber/timber, timber/masonry and masonry/masonry. 4.5mm, 6mm, 8mm and 10mm diameters are available in various lengths and are inserted with a hammer, insertion tool or power support tool. Ideal for use as a wall tie for laying in the mortar bed on new brickwork. Grade 316 is also available.
HeliTie Masonry Beam
The HeliTie Masonry Beam is the main concept to have resulted from the combination of the HeliTie Bar and HeliGrout. Where masonry has lost its load bearing capabilities the HeliTie Masonry Beam provides the existing failed masonry with the ability, not only to regain its original load bearing capacity, but to increase it. Two HeliTie Bars — 'one chord' — are inserted and bonded with HeliGrout in one bedjoint and another 'chord' is inserted in the same way between and 14 brick courses above. In this way, the HeliTie Masonry Beam converts the accepted compressive strength enabling building loads to be distributed evenly throughout the structure.
HeliTie Ground Screw
Used in combination with the HeliTie Masonry Beam, the Helical Ground Screw can be used as a standard pile and beam method of ground support. New foundations may also be cast on the Helical Ground Screw. The system is very quick and easy to install giving an efficient and cost effective solution. Light-weight equipment is used for installation and on-site testing. The unique design of the Helical Ground Screw has proven to be very versatile and its uses varied. It it very effective in tension allowing it to be used for retaining wall stabilisation and soil pinning operations for cuttings and embankments.
Reconnecting Party Walls with External Walls
CemFixes are installed with HeliGrout into clearance holes drilled to the required depth through the external walls and into the party walls.
Stabilising Bowed Walls into Joist Ends
BowFixes are inserted through clearance holes in the masonry and power driven directly into the joist ends. They are then load tested before being bonded into the masonry with HeliResin or HeliGrout.
Repairing Separated Masonry
CemFixes are installed with HeliGrout into clearance holes drilled through the near leaf and at least 75mm into the far leaf. The density of the ties will vary depending on site conditions.
Reconnecting Internal Walls with External Walls
Slots are chased out on the internal wall into the corner. Angled holes of approximately 10mm diameter are drilled from the corner into the external wall. A HeliTie Bar is then inserted into the hole and grouted with HeliGrout.
Repairing Brick Arch Lintels
A Helical Masonry Beam is inserted above the lintel and extended 500mm beyond the opening. Angled CemFixes are inserted through the lintel and into the beam above.
Repairing Cracks near Corners and Openings
Where cracks are less than 500mm from an external corner or a reveal, at least 100mm of HeliTie Bar should be bent around the corner and bonded into the return wall or bent and fixed into the reveal.
Stabilising Bowed Walls into Joist Sides
BowFixes are inserted through clearance holes in the masonry and first joist, then power driven directly into the second joist. They are then load tested before being bonded into the masonry with HeliResin or HeliGrout.
Creating Masonry Beams
Parallel lengths of HeliTie Bar are bonded with HeliGrout into chased out slots in the mortar beds between 1 and 14 brick courses apart and extended 500mm beyond each side of the opening to create a masonry beam. This beam not only spreads the building loads but also reinforces the masonry.
- A masonry beam restrains bowing. The presence of a stairwell and the absence of joists prevent BowFixes from being used in this instance.
- A masonry beam spreads vertical loads where cracking has taken place.
Crack Stitching
Lengths of HeliTie Bar extending 500mm either side of the crack are inserted into mortar beds with HeliGrout.
Repairing Failed Lintels
The HeliTie Masonry Beam uses parallel lengths of HeliTie Bar bonded with HeliGrout into chased out slots in the mortar beds between 1 and 14 brick courses apart and extending 500mm beyond each side of the opening.
Replacing Cavity Wall Ties
One point HeliTies are inserted using a hand tool or power support tool and, depending on site conditions, bonded with HeliResin or HeliGrout. Should site conditions prevail, the HeliTie can be driven into both leaves through a small pilot hole.
Helical Ground screw
Ground Screws can be used to provide additional ground support for a structure. A masonry beam is inserted above to spread loads. Reinforcement and grout are inserted into the Ground Screw. A load test is carried out on site and, if required, additional lengths can be added. Once the required load is attained, the Ground Screw can then be capped with reinforcement and concrete. The Ground Screws can also be used as a method of support for earth retaining walls.
Movement Joint
Slots are cut in the outer leaf every 450mm along the movement joint and a length of HeliTie Bar inserted. The HeliTie Bar is fixed on one side of the joint and sleeved on the other side along the whole length of the joint allowing normal movement but preventing lateral movement.