TRIMESH^®

Reinforcing Mesh
(Interior & Exterior Reinforcement Applications)

Product Description

The Trimesh^® panel is a lightweight construction system which can be used for erecting non-loadbearing elements such as mono or multilayered horizontal and vertical barriers as well as complementary structures such as risers dividing walls, internal curtain walls, thermal Insulation walls and floors.

The Trimesh^® panel is a spatial frame manufactured from an electrically welded high tensile steel wire of 2 mm diameter. The base panel has a rigid three-dimensional structure which can either be sprayed on site, or factory pre-cast to provide a monolithic base. The Trimesh^® panel can also be lined on one side with a layer of aluminium foil that acts as a type of ‘form work’ to compliment the spray application.

To achieve the superior Fire and Acoustic levels outlined in our test data, the Trimesh^® base must be sprayed with the LAF Group complementary products. (1)

The final product is a panel with two layers of mesh with diagonal stiffeners, sprayed with variable material thickness. The adopted final thickness will depend on the Fire Resistance Level (FRL), Sound Transmission Class (STC) Rating or Loading that is required.

The Trimesh^® panels are installed with the framing first and then with the joints lapped by joiner strips, in accordance with the adopted LAF methodology. Once fixed, the Trimesh^® panel is ready to be sprayed in two stages. The first stage is spraying up to the mesh. Some mesh is left exposed to provide satisfactory keying of subsequent coats. The second stage or final coat is then applied to the required thickness. When included the aluminium foil provides a backing for the spray application, and acts as a reflective thermal vapour barrier. The system complies with the requirements set out in the various Standards. In some circumstances the Trimesh^® can be "cast-in" between layers of form work in accordance with normal concrete wall construction practice.

Standards & Guideline References

When constructing special structures that fall outside of the LAF tested prototype and spans, it is important that reference be made to the applicable Standards and guidelines. Alternatively, a practising Structural Engineer may review the design parameters and provide conforming certification.

Materials

The various mortars should be applied by means of Mechanical Spray equipment. LAF have tested the Trimesh^® system in conjunction with various mortars: Alltex^® and Vermiduct^® are the most commonly used. The decision on which product best suites the application is to be made by the Specifier taking into account the following characteristics:

Additional Reinforcement

Additional reinforcement can be introduced in the form of standard deformed reinforcing bars, which must be installed in accordance with the relevant Standards and Codes.

Water-Cement Ratio

As with all cement based mortars, reducing or minimising the amount of water used in the mixing of the compound is imperative. Excess water should be avoided as this water will tend to ‘weep’ out of the mortar and contribute to the formation of small fissures as well as gaps. This will inevitably compound the degradation of the concrete mix.

A low slump mix will provide better adhesion onto the wall especially during the second application, and save Labour. This means there will be less material run-off.

Drying Shrinkage

The drying shrinkage phenomenon arises from the contraction in volume as a consequence of the evaporation of the interstitial water. The phenomenon affects all concrete structures but, in particular those with reduced thickness as the evaporation surface ratio is much greater compared to the mass of the wall.

This phenomenon can be reduced as follows:

• In some circumstances the use of man made fibres may reduce cracking as well as increase the abrasion resistance of the final product.
  
• Maintain relatively good ambience humidity. Wetting the finished product is good practice.
  
• Protect the finished product from excessive quick drying
  

Installation Methodology

Foundation

Where necessary, the specifier/designer may call for suitably constructed foundations with the inclusion of starter bars at specified centres. The starter bars may then simply be inserted into the holes previously drilled into the concrete slab. As the Trimesh^® panel is inserted over these starter bars, the correct location is of paramount importance.

Vertical element erection

The operation simply consists in the placing of the Trimesh^® panels over the foundations or slab and subsequently tying the Trimesh^® back to the starter bars or in some instances, clipping the panel with a pneumatic crimping tool.

To ensure that the panels are plumb and square, temporary propping and bracing is recommended.

Caution:

• Check the location of any openings to ensure the correct sequential programming for cutting openings into the Trimesh^® panels using an angle grinder, side cutters or nippers.
  
• Check if additional reinforcement is to be located within the Trimesh^® panel before they are secured to the starter bars.
  

On completion of the dry panel erection:

1. Install fixtures at openings (windows and door frames etc.).
2. Install electrical and plumbing services.
3. Ensure that the Trimesh^® structural integrity and continuity is maintained by installing joining strips at all vertical joints and securing these in place by means of pneumatically fixed steel rings.
4. Organise typical reinforcement nodes as per the manufacturer’s details.
5. Repair Trimesh^® at electrical and plumbing services installation.

NOTE: It is good practice to ensure that services do not travel horizontally for long distances. This reduces the risk of compromising the wall’s structural stability. Always ensure that any services ‘chased’ within the wall are rendered over with mortar satisfactorily.

Horizontal element erection

Generally installation will be in accordance with the traditional methods of a concrete slab construction. Suspended horizontal Trimesh^® installations, such as plenum enclosures etc., can be suspended from hanging rods which are installed at the correct locations in conjunction with other suspension systems, such as Unistrut, to carry services. Where a perimeter masonry element is available, the Trimesh^® may be wire tied to previously installed dowels or in some instances, or clipping the panel with a pneumatic crimping tool.

Caution:

• It is good practice to install a positioning angle to act as a reference guide and connection between the wall panel and the horizontal element at the ‘head’ of the horizontal Trimesh being installed.
  
• 
  When building a multi-layered element, ensure that the starter bars for the next wall section have been installed, that all the services have been installed, and that all the required reinforcement is located correctly and will be covered with the correct thickness of mortar prior to spraying.
  

On completion of the dry panel erection:

1. Install fixtures at openings (eg Access Panels, Light Boxes etc.).
2. Install electrical and plumbing services.
3. Ensure that the Trimesh^® structural integrity and continuity is maintained by installing joining strips at all horizontal joints and securing these in place by means of pneumatically fixed steel rings.
4. Organise typical reinforcement nodes as per the manufacturer’s details.
5. Repair Trimesh^® at electrical and plumbing services installation.
   

Mortar Spraying

Vertical elements

After having ensured that the correct spray compound is being used and that the walls are plumb, the mechanical spray plastering operations may commence.

1. Spray first coat to partially cover the mesh, then level.
2. Provide a scratch coat to ensure a subsequent and superior bond.
3. Position levelling screeds at the required centres.
4. Apply a second coat, until the required thickness is achieved
5. Trowel or Wood float as may be necessary.
6. Where required, apply a finishing coat.
   

Horizontal Elements

Again, check that the correct materials have been prepared for spraying. The slab should only be sprayed after the vertical elements have been completed and the proper reinforcement has been installed.

If using the foil-backed Trimesh^®, caution should be exercised when spraying to avoid overloading of the aluminium foil as the ‘wet weight’ of the spray compound can tear the foil, when located on the lower side (i.e. spraying from above).

1. Spray first coat to partially cover the mesh, then level
2. Provide a scratch coat to ensure a subsequent and superior bond
3. Position levelling screeds at the required centres
4. Apply a second coat, until the required thickness is achieved
5. Trowel or Wood float as may be necessary
6. Where required, apply finishing coat

Caution:

• Continuously ensure that the flow characteristics of the material are correct to avoid hose blockages.
• The use of leaky hoses should be avoided, as water loss at the hose joints will contribute to blockages.
• Keep the walls humid to reduce ‘Drying Shrinkage’.
  

Corrosion prevention

In high humidity and in wet areas spray materials should not be relied upon as a rust preventative coating. Vermitex^® materials are porous and will allow the passage of moisture through to the substrate. If a concern exists about moisture levels, the spray material may have to be top coated with an appropriate membrane coating. (1)

Note that in some circumstances the Trimesh^® may cause ‘galvanic reactions’ when in contact with particular metals, and suitable preparation work may be required. (1)

The Trimesh^® structural solution is a monolithic box type with a static behaviour similar to that of masonry load bearing walls, or to that of large precast panels. The Trimesh^® panel system may be employed in wall construction and be suspended from any superimposed (eg Concrete Slab, Beams etc.) element to circumvent the slenderness ratio conditions imposed by some of the Standards.

Trimesh^® is available in the following sizes: (Note: H = Distance between the two layers of mesh)

Note: The thickness and weight of the panels will vary proportionally with the overall applied thickness of Mortar. (1)

Health Statement

Trimesh^® contains no asbestos and presents no known health hazard before, during and after application. Normal precautions relevant to the handling of gypsum products apply: dust mask, eye protection and covering of sensitive skin.

NOTES:
1. Refer to LAF for further detail and information.
2. Refer to L & A Fazzini Manufacturing Pty Ltd for additional information on applicable thickness of spray cover to reinforcing bars.

For more information or MSDS on Vermitex^® ‘AF’ or any other products,

please see the technical data page, or contact: L & A Fazzini Manufacturing Pty Ltd

Email:sales@lafgroup.com