Costed: Roofing

Isabel Arogbo, quantity surveyor at Capita, provides an overview of rates for roofing finishes

There is a vast and varying spectrum of roof finishes – tiles, built up roofing, single ply membranes, metal sheet cladding, timber, green roofs, etc. Most are applied as either pitched or flat roof finishes, with a flat roof generally defined as having a pitch of 10° or less. 

Typically, compared to a flat roof, a pitched roof will require about 10% additional roof covering, although this clearly also depends on the particular circumstances including the desired finish. Consideration must be given to all, particularly to the use of the space below the roof and how that may be affected by the specified finish. 

It is critical to the installation of all roof finishes that contractual responsibility for design detailing isalways  defined and clear. 

As the applied finish plays such a critical part of the building’s life it is always worth giving it careful consideration. 

Costs given here exclude main contractor preliminaries and overheads and profit, roof structure, insulation (unless stated), drainage, etc.•


ROOFING FINISHES    

All prices quoted are exclusive of VAT and correct as of 4Q2014. Rates below assume works are undertaken in the London region and to an area of approximately 500m².

Assume costs of 5-10% lower than stated for work situated outside the South East


Tiled finishes

Rates can increase up to £400/m2 depending on the nature of the slate

Natural slate tiles, pitched, standard uniform size, underlay    £70-120/m2

Natural slate tiles, flat, standard uniform size, underlay    £60-110/m2

Synthetic slate tiles, pitched, standard uniform size, underlay    £55-80/m2

Reconstituted slate tiles, pitched, standard uniform size, underlay    £55-75/m2

Timber shingles, pitched, western red cedar, uniform length and size    £55-75/m2

Clay tiles, pitched, standard uniform size, underlay    £35-55/m2

Concrete tiles, pitched, standard uniform size, underlay    £30-50/m2

Fibre cement slates, pitched, standard uniform size, underlay    £45-65/m2

Metal finishes

Copper sheet roof, flat, with membrane    £80-175/m2

Copper sheet roof, pitched, with membrane    £95-200/m2

Copper standing seam roof, pitched, with membrane    £100-200/m2

Aluminium standing seam roof, flat, quilted installation, vapour control layer    £80-130/m2

Aluminium standing seam roof, flat, ridged installation, vapour control layer    £95-140/m2

Stainless steel sheet roofing, pitched    £105-160/m2

Lead roof covering, milled lead, laid flat    £85-125/m2

Lead roof covering, milled lead, to pitch    £90-135/m2

Zinc profiled roof, pitched, standing seam appearance    £60-120/m2

Membrane and built-up finishes

Bitumen three-layer modified bitumen system, laid flat    £70-120/m2

Bitumen two-layer modified bitumen system    £60-90/m2

Bitumen felt roofing system, laid flat, with solar reflective paint finish    £85-140/m2

Mastic asphalt, applied flat, to concrete substrate    £20-40/m2

Single layer sheet roof, warm roof covering, vapour control layer, insulation and water proof membrane    £90-140/m2

High performance rubber roofing, flat    £80-120/m2

High performance rubber profiled roof, pitched, standing seam appearance    £75-120/m2

High performance liquid applied membrane    £850-1100/m2

Air cushion roof (ETFE type roof)

Fibresheet roofing

Corrugated fibre cement    £30-40/m2

Extra over cost for transparent GRP sheeting to match    £20-30/m2

Glazed

Glazed roofing; traditional style with wire reinforcement    £550-700/m2

Glazed roofing; timber framed    £500-650/m2

Glazed roofing; aluminium powered coated framing with factory applied solar protection film    £350-500/m2

Landscape roof

Sedum roof, laid flat, with waterproof layer, separation layer, drainage and installation layer    £150-225/m2

Extra over cost of roof walkways

600mm x 600mm precast concrete slabs, laid directly and fixed on flat roof finish    £60-75/m2

1000mm wide rubber anti-slip walkway, laid directly and fixed on flat roof finish    £70-80/m2