Cladding costs over a lifetime

By - , Build 163

Designers and builders enjoy a broad and ever-increasing range of cladding options for walls and roofs. While appearance is a prime consideration, it is useful to consider the upfront and lifetime costs.

Figure 1: Residential roof claddings.
Figure 2: Residential wall claddings.

THE LIFETIME COST of a cladding considers how long it is likely to last, how much it will cost to maintain and how often it needs to be maintained. The following may help to narrow the options for a particular job.

What is most popular?

BRANZ surveys builders or designers of new dwellings to understand their choice of materials. From this, the market share of the various roof and wall cladding options can be assessed. Sheet metal remains the most popular roof cladding for new builds, with 55% market share in 2015, followed by metal and concrete tiles with 39%. For wall claddings, weatherboard profiles have been growing in popularity, used in 37% of new houses. Clay and concrete bricks, historically the most popular, have declined from 50% in 2005 to 38% in 2015, and weatherboards are poised to overtake them.

Lifetime costs

Maintenance for each of these claddings is based on maintaining a good appearance and weathertightness. This assumes a moderate environment – claddings in coastal, geothermal or industrial environments will require a different assessment.

Only direct costs have been included, as indirect costs will vary from site to site. Indirect costs such as scaffolding or edge protection, enhanced foundation or structural requirements, disruption from maintenance or replacement, and disposal costs at end of life may tip the balance in favour of more durable and lightweight claddings. All claddings require regular cleaning, and the cost is not in the lifetime cost.

Ease of maintenance should be considered when selecting a cladding, as surfaces that are difficult to access may be better suited to long-life, low-maintenance materials.

Sheet metal cheapest for roofs

The range of roof claddings assessed all offer a similar lifetime cost (see Table 1 and Figure 1). It is dominated by sheet metal options, led by textured metal tiles, which provide both a low initial cost and a long, low-maintenance service life.

Concrete tiles offer a similarly low upfront cost and long service life. Unpainted sheet metal has the lowest initial cost and offers a low lifetime cost with an expected 25-year maintenance-free service life. Precoated steel roofing offers a moderate service life, initial cost and lifetime cost.

Figure 1: Residential roof claddings.

For walls, wide range in cost and material

The cost and choices of wall claddings vary considerably more than roof claddings, perhaps reflecting their higher visibility (see Table 1 and Figure 2).

Figure 2: Residential wall claddings.

Corrugated sheet metal offers the lowest lifetime cost by a considerable margin but is less common on residential walls.

Weatherboard profiles offer a moderate lifetime cost across a range of materials – radiata pine, uncoated cedar, fibre-cement, prefinished aluminium and uPVC. For materials that require painting, the labour-intensive nature of painting weighs heavily on the initial and lifetime cost. Maintaining the appearance of stained timber requires frequent recoating, which also leads to a high lifetime cost.

Clay and concrete bricks offer the longest serviceable lifespan and, due to their low maintenance requirements, offer a lower lifetime cost than weatherboards.

Table 1 Initial and lifetime costs for claddings 

CLADDING TYPEAverage life (yrs)Initial cost ($/m²)Lifetime ($/m²)
Roof claddings
Metal tiles textured, recoat @ 40 and 60 years 60–80 50–60 3.5–4.4
Corrugated steel 0.40 mm zincalum, unpainted 30–40 40–50 3.5–4.4
Concrete tiles, repaint and repoint @ 35, 60 and 80 years 60–80 50–60 3.5–4.4
Corrugated steel 0.40 mm, prepainted, repaint @ 25 and 35 years 40–60 50–60 3.5–4.4
Corrugated aluminium 0.70 mm, no coat 40–60 60–70 3.5–4.4
Corrugated steel 0.55 mm, prepainted, repaint @ 25 and 35 years 40–60 60–70 4.5–6.0
Trough steel 0.55 mm, prepainted, repaint @ 25 and 35 years 40–60 70–80 4.5–6.0
Wall claddings
Corrugated steel 0.40 mm zincalum, unpainted, no maintenance 20–30 40–50 3.5–4.4
Corrugated steel 0.55 mm, prepainted, repaint @ 25 and 35 years 40–60 60–70 4.5–6.0
Sheet plywood and batten, painted, repaint every 8 years 40–60 90–100 6.1–9.0
Fibre-cement sheet 7.5 mm + PVC jointing, painted, repaint every 8 years 30–40 90–100 6.1–9.0
Clay or concrete bricks, repoint @ 35 years 60–80 160–170 9.1–12.0
EIFS 60 mm polystrene, repaint every 10 years 30–40 130–140 9.1–12.0
uPVC weatherboard, no painting 30–40 160–170 9.1–12.0
Fibre-cement planks 180 mm, painted, repaint every 8 years 30–40 150–160 12.1–15.0
Timber weatherboard, radiata, H3 150 mm, painted, repaint every 8 years 40–60 160–170 12.1–15.0
Aluminium weatherboard, powder coated, repaint @ 25 and 35 years 40–60 180–190 12.1–15.0
Timber weatherboard, cedar, 150 mm, no coat 30–40 180–190 12.1–15.0
Fibre-cement weatherboard 180 mm, painted, repaint every 8 years 30–40 200–210 15.1–18.0
Timber weatherboard, cedar, 150 mm, stained, recoat every 4 years 40–60 210–220 18.1–22.0

Cheapest not always most popular

Market share information shows that the cheapest claddings are not necessarily the most popular. Weatherboard profiles are not the cheapest wall claddings for initial or lifetime cost, yet they are the most commonly used.

Appearance and weathertightness is clearly very important, hence the preference for bevel-back weatherboards over rusticated. More expensive cladding options are likely to maintain their appearance for longer, and this may support resale value down the track. Real estate advertisements often highlight low-maintenance and long-lifetime claddings such as concrete tile roof and clay brick wall claddings. Lifetime costs may not always sway a decision but support well-informed decision making when choosing cladding.

Note

Thanks to the New Zealand Metal Roofing Manufacturers Association for providing data.

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Articles are correct at the time of publication but may have since become outdated.

Figure 1: Residential roof claddings.
Figure 2: Residential wall claddings.

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