Some thought the shine may have gone off clay bricks as a cladding material following the Christchurch earthquakes, but that’s not what BRANZ’s materials survey found.
ANALYSING THE QUARTERLY BRANZ materials survey (300 houses per quarter) shows some useful trends in building material use.
The BRANZ survey divides roof claddings into three broad groups:
- Steel – sheet steel with various profiles and coatings and metal tiles.
- Concrete – concrete tiles and flat concrete slab roof, usually with a membrane skin.
- Other – includes aluminium and copper sheet, asphalt and fibreglass shingles and sheet membranes on plywood sheet.
Steel has houses covered
Steel roof cladding dominates the new housing market – its share is trending upwards towards 80% (see Figure 1). Concrete is on a downwards trend, although it had a relatively steady share between 2004 and 2006 at approximately 20%.
For dwelling reroofs, steel remains dominant – its share increased from 2003 (80%) to 2009 (94%), but it has since trended downward slightly to 90%. Concrete roof cladding has a very small and downward trending share of the reroof market (between 2 and 4%) and asphalt shingles and sheet membranes on plywood sheet are the other main claddings used when reroofing.
Non-residential roofing sees alternatives rise
Steel is again the main roof cladding type in non-residential buildings. However, steel’s share has been trending downwards in favour of other roof cladding types from a peak at 92% in 2005 to 79% in 2011.
Steel has a near 100% share in industrial and farm-type buildings, and as these buildings have large roof areas, they dominate the overall percentage for all non-residential buildings.
Concrete has remained steady with a minuscule share (1–2%) of the market throughout the period.
There is much more variety in the types of wall cladding used than roof claddings. Where multiple claddings have been used, the share of each cladding in each house has been included.
Don’t knock brick
Clay brick dominates in new housing, particularly in the Canterbury and Waikato regions.
Weatherboards have been increasing in share, whereas the monolithic look of external insulation and finish systems (EIFS) and stucco claddings have been declining (see Figure 2).
In post-earthquake Christchurch, clay brick’s share has increased. Before the earthquakes, its share in Christchurch was approximately 45%. Since the earthquake, its quarterly share has been approximately 60%. As building activity picks up, we will continue to follow this.
Weatherboards in vogue for reclads
The choice of wall reclads for dwellings tends to be very volatile.
Clay brick has the smallest share and, since 2007, has been trending downwards. EIFS and stucco cladding have also been trending downward.
Weatherboards have been the predominant cladding in the reclad market since 2007 (see Figure 3).
Steel usurps concrete on non-residential walls
In non-residential buildings, steel and SIP (structural insulated panels) are the dominant wall claddings (see Figure 4). In 2008, these became more common than concrete – tilt slab, blocks and panels.
Steel has a large share in farm buildings as well as a strong share in both storage buildings and factories.
Concrete has been trending downwards, largely due to the growing prevalence of steel in industrial buildings.
Articles are correct at the time of publication but may have since become outdated.