While quality can be hard to describe and quantify, there are certain established standards and guidelines that, if followed, should result in a quality building.
BUILDING QUALITY is not easily defined or measured, and definitions of building quality have been debated for many years.
BRANZ has a research programme that aims to shed light on building quality issues and forge a path to better quality in construction.
Three levels of quality
BRANZ Study Report SR380 What is quality in buildings? discuss three levels of quality:
- Basic quality, or buildings that meet minimum standards without significant defects.
- Enhanced quality, with a focus on buildings fit for purpose for current and future users.
- High quality, for buildings that are ‘beyond good’.
Level 1 – basic quality
A basic-quality building complies with the Building Code in its design and construction. Its quality of finish is, to a tradesperson, standard, and the aesthetics are not generally objectionable to its users and public at large.
Deciding if an issue is a defect needing remedy is resolved by reference to, in order of precedence:
- the contract
- the building consent documentation
- manufacturers’ specifications
- relevant standards
- the MBIE publication Guide to tolerances, materials and workmanship in new residential construction 2015.
New housing has a 12-month defect repair period, by regulation. This is an incentive for builders to get it right first time and to avoid call-backs that can be expensive to remedy.
Level 2 – enhanced quality
An enhanced-quality building may have features beyond the requirement of the Building Code including enhanced energy and water use performance. These measures often recover the extra initial costs in a few years.
Buildings may also have increased structural strength for possible future changes in use and flexible spaces that can be adapted by users for different purposes.
Houses built to the New Zealand Green Building Council 6-Homestar standard will cost about 1–3% more than a standard house of about 4-star rating, depending on the particular measures used.
Non-residential buildings of enhanced quality may have sustainable features and, at a minimum, be efficient in energy and water use.
Designing for all ages and abilities
Universal design houses have features facilitating use by people of all ages and abilities over time and certainly enhance the user-friendliness of a dwelling. For most single-storey new houses, these add about 0.5% to the house cost.
Features include minor changes in the entrance and internal layout, wider doors and strengthening of walls for grab bars and other fittings.
Retrofitting of existing houses is significantly more expensive. It seems sensible that all new housing should have universal design features, which can be seen on the Lifemark website – www.lifemark.co.nz.
Level 3 – going beyond good
High-quality buildings are usually top-end houses or one-off designs of company, regional or national importance. They may be prestigious office, social or cultural buildings or public-facing buildings for education and health facilities. They will have the features of an enhanced quality building plus materials that are top quality and low maintenance.
The designs will be very much client-focused, and they may be award winners. Aesthetically, they are often innovative for their building type and generally invite favourable comment from the public and the owners.
Personal preferences drive priorities
Just where the boundaries lie between the three categories is a matter of preference for owners and users. Different owners will have different priorities, and existing buildings may not be able to be transformed to the requirements of different owners.
Purpose-built buildings usually best satisfy the needs of their owners. A quality building will be designed so layouts and plant can be adapted as owners’ and users’ needs change due to technical, social and financial influences.
Green labels add premium
Green-rated buildings such as Homestar, Greenstar and the US Leadership in Energy and Environmental Design (LEED) would be considered to fall within at least the enhanced quality group.
In a comparison study of 10,000 office buildings across the US (approximately 50% green-rated, 50% not rated), green features added about 6% to the rents and about 16% to the building selling price.
The study adjusted for age, floor area, storeys, quality classification, location and other factors.
The premium was mainly due to energy and water savings associated with green buildings but also partly due to intangible effects of the green label itself.
Evaluations point to problems
What owners and users think about the quality of their buildings can be assessed through post-occupancy evaluations that are carried out in many countries.
In New Zealand, evaluations have been carried out on over 170 mainly commercial buildings.
The most common complaints relate to air quality in commercial buildings and lack of space in education buildings. About 30% of those buildings have these attributes rated as their worst feature.
In apartment buildings, the worst attribute was security, with 16% of respondents raising the issue.
Good design pays
The operating and maintenance costs of a commercial building over 25 years is about 50% of the initial cost. However, business costs for staff, equipment and consumables are about 11 times the initial cost. Hence, design features that are conducive to staff productivity can have big paybacks.
In summary, a quality building will provide value for money not only for its initial cost but for its users over the life of the building.