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Curtain Wall Procurement

• Introduction
• The Rate/Size Diagram
• The Star System
• Procuring Little Gems and Big Sheds

Introduction

The intention of this page is to assist those procuring curtain walling to understand the nature and structure of the UK cladding and curtain walling industry, and to help in compiling tender lists of appropriate, and comparable, specialist sub-contractors. The origins of this page go back many years but this is, as far as we are aware, the first time that this information has been made available on the internet.

The Centre for Window and Cladding Technology (CWCT) at Bath University [www.cwct.org.uk] explain the general principles in their courses but prefer, quite sensibly, not to name-and-group their member companies, thus preventing any accusations of a conflict of interest. The CWCT Curtain Walling Procurement for Building Professionals course is highly recommended for anyone with the need to understand the process in more depth than can be explained here.

The Rate/Size Diagram

The key point to understand is that there is a surprisingly direct correlation between the cost of a curtain walling sub-contract and the rate/sq.m. of the curtain wall - as the overall cost of the sub-contract increases, so will the rate/sq/m.

If your project is somewhere in the median zone you will have a wider choice of suitable and comparable specialist contractors. But if you have a small-and-complex curtain wall (a "Little Gem"), or a large-and-simple curtain wall (a "Large Commercial", also referred to as a "Big Shed"), then finding suitable contractors will be much more difficult.

This is best explained graphically in the left-hand diagram below:

The diagram above, originally created by architect Andrew Brown when Head of Technical Services at Sheppard Robson, has been used for many years by the CWCT to explain the structure of the curtain walling industry. The diagram on the right is Andrew's more recent version.

Architect Andrew Brown [www.andrewkb.net] has further refined the idea - see the right-hand diagram above - by grouping together companies with similar capabilities and overlaying these groups on the CWCT diagram. You can read more about the Star System, and how best to handle Little Gems and Big Sheds, below.

The Star System

The Star System groups together companies with similar capabilities and is intended solely to assist in selecting appropriate, and similar, companies when compiling tender lists. The 'star system' (with its analogies to the similar system for hotels) has been deliberately chosen to reflect the service that a company offers, not the quality of that service. The lists below are representative, not comprehensive, particularly in the 3-Star and 2-Star categories where the market is notoriously fluid as previously well-known companies fail and new ones are formed. Those companies highlighted yellow are current members of the CWCT.

5-Star Companies

• Capable of the very largest curtain walling contracts / Unlikely to be interested in contracts under £~5m.
• Generally European companies designing, fabricating, and installing. Capable of highly bespoke work.
• Representative list of companies currently (May 2011) operating in the UK.
• Permasteelisa/Gartner/Scheldebouw : www.permasteelisa.com
• Yuanda Europe - www.yuanda-europe.com

4-Star Companies

• Capable of curtain walling contracts up to £~15m / Unlikely to be interested in contracts under £~2.5m.
• Generally European companies designing, fabricating, and installing. Capable of most bespoke work.
• These companies are differentiated from 5-Star companies primarily by the maximum contract value of the work they are capable of handling, and from 3-Star companies primarily by their ability to handle more technically-complex projects.
• Representative list of companies currently (May 2011) operating in the UK.
• Bug-Alutechnic AG - www.bug.de (English language website, but no UK office?)
• Felix UK - www.felix-constructions.ch
• Focchi - www.focchi.it (English language website, but no UK office?)
• GIG Fassadenbau - www.gig.at
• Lindner Facades Ltd - www.lindner-schmidlin.com
• Mero-Schmidlin (UK) plc - www.mero-schmidlin.com
• Metallbau Fruh - www.metallbau-frueh.de
• Schneider GB Ltd - www.schneider-facades.co.uk
• Seele (UK) - www.seele-online.com
• Structal (UK) - www.structal.co.uk

3-Star Companies

• Capable of curtain walling contracts up to £~10m / Unlikely to be interested in contracts under £~500k.
• Generally larger UK companies fabricating and installing systems (Hueck, Kawneer, Reynaers, Schuco, Technal, etc.). Capable of some bespoke work.
• These companies are differentiated from 4-Star companies because they generally handle less technically-complex projects, and from 2-Star companies primarily by the maximum contract value of the work they are capable of handling.
• Representative list of companies currently (May 2011) operating in the UK.
• Dane Architectural Systems - www.danearchitectural.co.uk
• English Architectural Glazing - www.eag.uk.com
• McMullen Architectural Systems - www.mcmullengroup.co.uk
• Parry Bowen - www.parry-bowen.co.uk
• Red Architectural - www.redarchitectural.com

2-Star Companies

• Capable of curtain walling contracts up to £~2.5m (or less).
• Generally medium-size UK companies fabricating and installing systems (Hueck, Kawneer, Reynaers, Schuco, Technal, etc.). Some may sub-contract the installation. Some are specialised and capable of bespoke work.
• Representative list of companies currently (May 2011) operating in the UK.
• MAG Hansen - www.hansengroup.biz
• SIAC Construction - www.siac.co.uk
• Stoakes Systems - www.stoakes.co.uk
• Structura (UK) - www.structura-uk.com

1-Star Companies

• Capable of curtain walling contracts up to £~1m.
• The smallest UK companies, generally offering curtain walling alongside windows and simple metal panel/sheet cladding systems. They will almost certainly rely heavily on the design expertise of the system companies (Hueck, Kawneer, Reynaers, Schuco, Technal, etc.) and will probably sub-contract the installation.
• System companies will normally supply a list of suitable contractors, using their system, in a particular geographical area and this is probably the only way to compile a suitable tender list for projects of this size. Membership of the CWCT, see above, may be an indication of the company's aspirations but should not be taken as any confirmation of their financial stability. Few companies this size seem to last this size for very long as profit margins on very small curtain walling projects are generally unsustainable - the companies either take on larger projects, sometimes with disastrous results, or drift away from the market.

Procuring Little Gems and Big Sheds

Little Gems

• "Little Gem" : A project with an unusually small amount of more complex cladding.
• Unless the value of the cladding sub-contract is very low, say below £250k, these projects are best handled by 4-Star companies, but it must be accepted that variations to their normal financial model will need to be agreed. In particular, they will probably need to allocate relatively more design time than for larger projects and this will have the effect of driving the rate/sq.m. up still further.
• There are a small number of UK cladding and curtain walling companies, generally operating at the "artisan" level, who may be capable of complex projects under £250k, but these companies do not have a good survival rate and none are listed above.

Big Sheds

• "Big Shed" : A project with an unusually large amount of less complex cladding.
• Most 3-Star companies are very capable of handling these sub-contracts technically, but may need extra logistical assistance and will very often fail the financial criteria imposed by some main contractors and client-employers.
• It is probably no coincidence that a large number of the business failures in the UK cladding and curtain walling industry have been caused by 3-Star and 2-Star companies over-stretching themselves to take on large projects at low rates/sq.m.
• For example (1): The company might be capable of delivering a much larger project than its typical project but will require more time than is allowed for in the overall construction programme. Meeting the construction programme might require sub-contracting some of the fabrication, or hiring additional gangs of installers, and these will require additional management time. The cost of the extra management time may affect the (already-low) profit margins, or failing to provide the extra management may lead to delayed, or sub-standard, work.
• For example (2): The company might be capable of delivering the project on time and on budget but, in doing so, the project will represent a higher percentage of the company's annual turnover than is normally allowed by the main contractor. It is not unknown for main contractors to relax criteria of this type, just to ensure that they can bid competitively for the overall project, but then maintain their standard (lengthy) payment terms, placing unreasonable pressures on the cladding company's cash flow.

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