News

Download this press release as a PDF. 

The new building standards include specific requirements for lapping Ductile wire mesh. As trusted experts in the field, Wireplus made sure with the Department of Building and Housing that our instructions in this regard are 100% accurate.

This means that following the Wireplus instructions, your wire mesh will meet building standards. Not lapping the mesh correctly creates the risk that your concrete slabs will fall foul of the law.

In simple terms: All Ductile wire mesh has to be lapped 1 square + 50mm, with minimum lap of 150mm, as per the Wireplus spec sheets.

To help make sure your slabs are constructed correctly, we’ve put full details about the lapping requirements here.

Download the guide as a PDF. 

Lapping mesh details 

Welded Reinforcing mesh Lap-splice requirements are set by the NZ Standards Association in NZS3101:2006 Code of Practice for the Design of Concrete Structures and are subject to a number of contributing factors as follows:

1. 1. Type of Bar used: Plain or deformed
2. 2. Diameter of Bar
3. 3. Spacing of main bars or ‘Edge bars’ where applicable.
4. 4. Style of mesh: 
5. a. Standard configuration with all wire spaced equally and perimeter bar 
6. b. Double edge 
7. c. Mesh without perimeter bar

You should always refer to the Wireplus mesh specification for the correct lapping. From the New Zealand Standard NZS3101:2006 the ‘relevant clauses’ are:

(NZS3101:2006 C8.6.8.2) “Development length of welded wire fabric-cross wires considered... An embedment of at least two cross wires 50mm or more beyond the point of critical section is adequate to develop the yield strength” This clause requires the lap to be 1 mesh square plus 50mm and any bar extending from the outermost wire (overhang) is not part of the lap.

(NZS 3101:2006 C8.6.4) “The development of plain bars in tension must not rely on straight development length as a result” Mesh made from plain wires can only be lapped according to the above clause. NZS3101:2006 C8.6.8.2.

Notes

1. Wireplus mesh is produced to meet AS/NZS 4671:2011 and laps calculated based on NZS3101:2006.

2. Design accuracy is the responsibility of the designer or specifier and all designs must meet NZS3101:2006

3. Lap lengths can be varied from the above if sufficient testing is carried out. Testing would need to be sufficient to ensure statistical validation of the obtained results and be carried out and reported on by a credible testing agency. It would be expected to include lap length tests, cross wire weld strength tests and specify all the relevant parameters which should include the minimum 28 day con- crete compressive strength and wire mesh fabric properties (verified as meeting or exceeding AS/NZS 4671). The assessment would be required to look at the potential impact on concrete crack formation at high stress levels, i.e. the lap length test performance may be adequate but additional lap length allowance is still required to limit crack formation resulting from loss of reinforcement bond. Such testing and assessment would normally be expected to be accompanied by a technical opinion from a building professional.

Download this press release as a PDF.   Download the Ductile Mesh Brochure as a PDF.  The new Ductile Plus 500E mesh from trusted Kiwi building supplier Wireplus does more than meet all the requirements of the Department of Building and Housing’s new standards... ...read more

Wireplus Ltd Continues Proactive New Product Development to Ensure Customers can Meet the New Standards Wire mesh that meets the Department of Building & Housing’s new Earthquake B1 Compliance standard is now available from Wireplus Ltd in both Christchurch & Auckland.... ...read more

In a rare move, New Zealand authorities have placed a trade barrier on imports of Chinese wire nails following an investigation that found they were having a negative impact on a local manufacturer. The Ministry of Economic Development (MED) began investigating the issue late last year after... ...read more

Wireplus Ltd are proud to be members of the Buy New Zealand Made campaign. Our Reinforcing Mesh and Nails are manufactured right here in New Zealand We purchase our wire from Pacific Steel whose products are made from 100% locally sourced recycled steel and metal including discarded car... ...read more

Wireplus are pleased to announce the appointment of our new manager Ryk Kleynhans. Ryk has an extensive management background in manufacturing businesses and officially took over the role on the 1st November 2010. Over the next few months Ryk will endeavour to meet with customers and suppliers to... ...read more