Technical issues in MDH

This Issue This is a part of the Changing face of building feature

By - , Build 175

BRANZ has found that unresolved issues with medium-density housing may impede its use.

SPACE FOR NEW DETACHED HOUSING developments has declined in some parts of the country as New Zealand’s population has increased. Medium-density housing (MDH) has been seen as a solution for continued urban intensification.

However, as recent BRANZ research shows, the building industry is telling us that there are technical issues associated with MDH that risk limiting its uptake by consumers at a time when it presents a potential solution to restricted land supply.

Industry’s main concerns

To identify technical issues with MDH, BRANZ asked the construction industry and government officials to identify their most pressing concerns.

Based on these conversations, a clear picture emerged regarding what the industry sees as the most important issues. The main themes raised were the risks associated with fire safety, weathertightness and acoustics. Of the issues raised, the most prominent included:

  • the potential of façade flame spread
  • incorrect use and installation of fire safety products – for example, fire collars
  • the applicability of Building Code clauses to MDH
  • external water ingress
  • noise transfer
  • the skillset and general capability of all building professionals involved in consenting, design and construction.

Underlying issues identified

While there was widespread industry consensus on what the most important technical issues with MDH are, it was clear that those we spoke with feel there are deeper issues that underlie them. This was most evident in the tension observed between designers and builders.

We noted that they frequently disagreed with each other on a range of issues such as the buildability of design, different cladding materials and how to manage junctions.

Tensions between professional groups were evident as we talked with different parts of industry. These included a perceived lack of guidance from the Ministry of Business, Innovation and Employment regarding fire-rated cladding and frustration with building consent authorities when assessing complex design against compliance criteria.

This shows that, while industry stakeholders do encounter technical issues with MDH, in some cases, the issues raised related to frustration in dealing with the regulators. It was obvious that government also experiences some frustration.

More than just technical solutions needed

The study’s findings into what those in industry are experiencing are consistent with previous MDH research suggesting that tackling issues with MDH is complex. Relationships between building professionals and government institutions are important but can be challenging for both parties.

The building industry itself is an environment where professional groups have their own distinct roles. They are required to build working relationships and work with others with different perspectives if they are to be successful.

Adding another layer to this is the difference in drivers and priorities between building professionals and government institutions, which has the potential for misunderstanding and frustration.

Our research suggests that some technical issues in MDH are occurring due to the regulatory and communication systems in which MDH is designed, consented and constructed. Technical issues may, therefore, require more than just technical solutions, presenting a challenge for the industry as well as the regulators.

Opportunity to align with the Accord’s ethos

Government has already recognised this situation. It has put in place several initiatives to enable relationships to be better with the aim of enabling industry to do what it does best – design and construct New Zealand buildings that are fit for purpose and meet need.

Prime examples are the goals of building trusting relationships and acting with collective responsibility set in the government’s Construction Sector Accord. The Accord aims to encourage the industry to work in a collaborative and inclusive way and to promote behaviour that cultivates trust and collaboration.

Being part of the solution

Future MDH research could contribute to the goals of the Accord by paying attention to regulatory and institutional changes required to commit industry stakeholders to address technical issues through a more integrated course of planning, design and implementation. Our advice may help them, and we look forward to being part of the solution.

For more

For further information on this BRANZ medium-density housing research, read Study Report SR428 Medium density housing technical issues available on the BRANZ website at

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