Masonry Repairs
Helical remedial products have been independently and vigorously tested in a wide range of common materials.
Helical remedial ties are made of stainless steel, corrosion resistant and flexible to accommodate natural building movement. They are easy to install and test in the building under repair, leaving nothing to chance.
Where drilling through a brick face is not acceptable, insertion of remedial ties through the mortar bed should be considered. As long as the mortar is strong and in good condition, this form of wall crack repair should be satisfactory. An alternative installation method is to use angled drilling which is used in special circumstances.
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Maclennan have been experts in designing, installing and guaranteeing systems for over 30 years.
Wall Ties
Using the latest 8mm diameter grade 316 austenitic stainless steel helical wall ties, we can install new ties quickly and easily and still provide you with a guarantee.
If you see horizontal cracking in the walls within your property and you have a cavity wall, there is a chance that over time moisture has gotten inside of the brickwork. When this happens, existing wall ties can begin to corrode and expand. Lifting the the existing brickwork and causing cracking.
The cracking should appear ever 450mm vertically. MacLennan can help you complete a wall crack repair by isolating the old steel wall ties. Once isolated, future damage can be prevented through the installation of new wall ties. As our new wall ties are stainless steel, they are less likely to corrode. With one of these ties we can get between a 1.5kn and 2.5kn pull out to make sure this is the correct tie application. There are a numerous amount of variations of ties we can use to suit all building materials.
Testing and Spacing
Pre-specification testing should be included as a routine part of the building survey. At least one, and preferably two, ties should be inserted into each elevation at different levels to determine the minimum pull out load obtainable from both near and far leaves. This minimum load should be used as the basis for deciding the density of ties to be installed. This testing is carried out by all Maclennan Surveyor’s when contracts are awarded or for a small cost at tender stage. For a small contract at least 10 ties must be tested; on large projects 5% of all ties should be tested. For most applications (buildings under 30m high and areas with a maximum wind speed of less than 46m/sec) the minimum tensile proof load is 1kN based on a tie density of 2.5 per m (900mm x 450mm centres). This excludes cladding form masonry and substrates below 100mm deep.
Independent Testing and Approvals
Helical remedial products have been independently and vigorously tested in a wide range of common materials. The testing programme is on-going and to date has been carried out by the Civil Engineering Department of Oxford Brookes University; the Civil & Structural Engineering Department of Middlesex University; The Transport Research Laboratory, Crowthorne and the Building Research Establishment, Garston
Why should I work with MacLennan?
WE’RE INDEPENDANT
We Design, supply and install. There's no split responsibility with MacLennan.
WE’RE PASSIONATE
MacLennan live and breathe waterproofing, have a look at one of our free CPD seminars and find out!
WE’RE GUARANTEED
MacLennan has the most comprehensive guarantees and insurances in the industry.
Other Types of Masonry Repair
Bowing Wall
This is a very common issue found on the end of gable walls within terraced housing and old properties where the floor joists are running between the front and back of the property. Since the floor joists run parallel to the wall, the wall isn't properly connected to the building's structure. MacLennan can provide a quote to connect the wall to the floor and ceiling joists, and if needed, to internal partition or spine walls.
Delamination
Delamination is a form of bowing which happens in large thick solid walls where the internal skin has come away from the external skin leaving the rubble-filled void in the middle of the wall to drop giving you the impression of bulging from the outside but no structural damage to the inside. We can reconnect the external masonry back to the internal masonry avoiding the need for a costly rebuild.
Wall Tie Replacement
Wall ties are an important structural component ensuring the stability of the outer leaf of a cavity wall against wind loads. The condition and number of wall ties in the structure are important and where corrosion has set in or wall ties are missing or broken, then remedial ties will be required. Solid masonry may also delaminate through broken headers or deteriorated mortar and require remedial tying to ensure future stability.
