CONCETE ROOF TILES - THE MOST ECONOMICAL AND BEST LOOKING ROOFING MATERIAL:

Last conducted in 2007, the survey uses data gathered in August 2009 from several sources. It focused on three building models, a 57m² (floor area) house, a 134m² house and a 1 158m² commercial building. The results of each have been published by the CMA in three leaflets, one for each model.

CMA director, John Cairns, said the survey assessed completed roofs built with trusses which allow for the inclusion of ceilings and underlays, and in each case concrete tiled roofs proved the most cost-effective material.

“An increasing number of low-cost housing developments are using roofs built with trusses as they have better insulation and aesthetic properties and ultimately make for much sounder long-term investments,” observes Cairns.

Factors such as floor area, roof area, pitch and truss spacing, among others, as well as cost factors such as truss and timber sundries, roof erection, roofing material and fixing, were taken into account.  Prices were based on complete roof structures, however, fascia boards and gutters were omitted from the survey because these are optional items which make no difference to the costing. Likewise no provision was made for underlay, membrane or ceiling construction.

Cairns says the figures represent a “snapshot ” in time and that price fluctuations of materials and labour will vary from product to product as time passes.

Certain assumptions were made to simplify the costing model for these buildings. For instance, while some housing developments comprise many units and developers/contractors can negotiate special project discounts, the majority of builders construct one-off projects and are therefore obliged to source roofing materials from their local suppliers at less advantageous prices.

The survey takes the following into account:

• Roof truss prices are based on standard industry pricing practice
• All costs are based on August 2009 figures
• Labour costs for the erection of the timber structures and the fixing of the roof covering material are included in the cost comparison
• General sundries exclude fascia boards and barge boards
• The cost of gable masonry has been excluded as it is constant for all roofs
• The rates exclude VAT
• Waste is included in all calculations.
 
The updated survey focuses on two models for concrete-tiled roofing in the 57m² house category, one using a conventional concrete-tiled roof, and the other deploying a roof using The CMA Roofing System. The latter, which has been awarded an Agrément certificate, was introduced in 2005 to make the concrete-tiled roof even more affordable, and the results of the current survey confirm this.

The R/m² costs for a concrete-tiled roof using the CMA Roofing System at R186 are 8% lower than those of corrugated-iron sheeting at R202, whereas the R/m² costs for the house using conventional timber trusses with concrete-roof tiles are 1.5% less than the cost of corrugated-iron sheeting. Furthermore, when one takes maintenance costs over the lifespan of both products, concrete-roof tiles, with little or no maintenance requirement, are likely to outperform corrugate iron sheeting.

Other materials such as pre-painted IBR metal sheeting, corrugated-fibre cement sheeting, and pressed-metal tiles were also included in the 57m² house comparison. It revealed that The CMA Roofing System costs 26% less than the R234m² of pre-painted IBR metal sheeting, 36% less than the R253m² of corrugated-fibre cement, and 43% less than pressed metal tiles at R267m².
 
Pre-painted metal sheeting, pressed metal tiles, natural slate and fibre cement slate were the materials selected for comparison with the through-colour concrete roof tiles used on the 134m² house and the 1 158m² commercial building.

The concrete-roof tile cost of R249m² on the house was 4.5% lower than the R260m² of pre-painted IBR sheeting on the same structure. Concrete-roof tiles cost 18.5% less than the R295m² of pressed metal tiles, 75% less than the R437m² of natural slate, and 82% less than the R454m² of fibre-cement roofing.

The R300m² concrete-roof-tiling cost for the office building was just under the R305m² for pre-painted IBR sheeting and close on 10% lower than the R329m² costing of pressed metal tiles. It was also 64% lower than the R492m² natural slate amount and 67% lower than a fibre-cement-slate roof, which came in at R502m².

Certain assumptions were made to simplify the costing model for the commercial building. For instance a floor area of 1 158m² was chosen arbitrarily and has no special significance other than being fairly representative of architectural practice. The roofs were all pitched at 26º as it was felt that in most circumstances this would be an architectural design feature of the building.

Cairns says the survey clearly demonstrates that property developers can have the best of both worlds on roofs built with trusses – attractive roofs which enhance the value of properties at the most cost-effective prices.  This is especially so at the lower end of the market.

The leaflets are available at no charge from the CMA. Contact Pam on (011) 805 6742 or on main.cma@gmail.com

The timber framework of a typical example of The CMA Roof System is subjected to stringent load testing prior to receiving Agrément certificate no.2003/302.

The Golf Course Ext Development, an affordable housing initiative adjacent to the King Williams Town Golf Course, in the Eastern Cape, the first housing project in which the recently introduced CMA Roofing System was used.

DATE:    January 2010
ISSUED BY:    David Beer Communication Consultants
FOR :   Concrete Manufacturers Association 
ENQUIRIES:    John Cairns (CMA) Tel: (011) 805 6742 ; David Beer Tel: (011) 478 0239 or 082 880 6726.