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The Art of Feasibility

How to start up a school building project— the art of feasibility

Building works are costly to commission, but the consequences of poorly planned works are even costlier if they go wrong during or after construction.

Schools should seek expert advice in the planning of building works— a well-thought out feasibility study completed by an expert will highlight the risks and costs of planned building works, to enable the school make a decision on whether or not to proceed with the work, and, if the school does decide to proceed with the work, will provide the foundation for the justification for funding.

Project managers, surveyors and even builders may be able to carry out or contribute to a feasibility study, but in our opinion an architect (at senior, partner or director level) experienced in school projects will be best placed to provide the rounded knowledge that is required to carry out a thorough feasibility study at the planning stage. Beware of practices who assign feasibility studies to junior or less experienced staff to complete.

For example, we recently worked on a school re-glazing and re-cladding job on which an earlier feasibility study had been commissioned from a surveyor. Although, the surveyor had done a fair job in analysing the concrete failure and estimating the cost of the re-glazing and re-cladding works, they did not have sufficient skill or experience address the following issues:

1. The fact that the classrooms overheated due to solar gain in summer. There are software packages, Class Cool and Class Vent, which can be used to calculate the correct glass specification to reduce solar gain, and the correct opening window sizes to sufficiently ventilate a classroom. These requirements are not found in the Building Regulations Approved Document but in DFES’ Building Bulletin 101, which has the same legislative weight as the approved document. 

2. The fact that concrete failure was caused by approximately 1 km of cold bridging— interstitial condensation within the exposed building structure— and that the new cladding and glazing should be designed to remove or prevent future cold bridging in order to avoid a continuation or escalation of the problem. 

3. The fact that removal of failed concrete from a reinforced concrete frame building is noisy work and needs to be carefully programmed to reduce affecting normal school business (unless classrooms are decanted, at additional cost). 

4. The fact that air-conditioning cables running across the building elevation needed to be rerouted, and the air-conditioning units sited next to the windows and cladding needed to be decommissioned for the duration of the building works. The existing air conditioning units were old and were unlikely to restart after decommissioning and so needed to be replaced.

Unfortunately, the school had bid for, and obtained funding based on the recommendations of the earlier feasibility study. Because the cost and complexity of the work had been underestimated by the surveyor, we had to carry out a number of value engineering (cost cutting) exercises to enable the project to be completed despite the oversights. The school could have had a better result if they had gotten a better feasibility in the first place.

Do not be shy of seeking a second opinion or getting a reference for your architect / surveyor etc.

An experienced professional will advise the school on what additional consultants are required (structural engineer and mechanical and electrical services engineer for example) in order to plan the job properly.

It is important that necessary surveys are carried out at an early stage to gather as much relevant data as possible. See these as a necessary but preventative cost— surveys help to identify and highlight potential risks (and hidden costs) to the project. Your architect will advise you on the surveys required for the feasibility study.  

Feasibility studies and reports come in all shapes in sizes, but are only worth their weight if they achieve their objective. This varies from project to project, but typically a feasibility study should aim to achieve the following:

  • Clarify and test the clients brief. The brief may be a single project— such as a classroom, staff room extension or sixth form centre— or a group of projects or list of building defects that need addressing (leaky rooflight above classroom X, cracked concrete above the hall, overheating of classrooms in summer etc.). 

  • Identify and appraise different options for achieving the requirements of the brief in a way that will enable the school to decide which option is the most appropriate or feasible option to implement. This should include a cost estimate of the various options (typically estimated by a quantity surveyor or building estimator, then compiled and presented by an architect). 

  • Identify risks and other hidden or abnormal costs, and recommend how these risks may be avoided or reduced, and advise on the cost of these risks or the cost of avoiding these risks. An example of a common risk would be: asbestos removal. 

  • Draft a programme for building work and advise on the best way to procure a competitive price for completing the work. 

A feasibility study is NOT:

  • A design. It is the necessary groundwork at the early stages of a project which will help clarify the project brief. Repair and maintenance work may require very little, or no design input at all, but it may need the specialist knowledge of a designer (for example, conservation knowledge if working on a historic building more than 60 years old.)

 A good design:
  • Meets the criteria set out in a good feasibility study.  

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Case Study: Concrete Repairs to ‘60s RC frame buildings

The main teaching block before refurbishment

Queen Elizabeth Grammar School, Faversham 

The main teaching block and science block of the school were built in 1967. Both are reinforced concrete frame buildings that featured exposed reinforced concrete columns and window transoms; the main block has reinforced concrete balconies on the rear façade. 

The exposed concrete was in very poor condition; sections of concrete were spalling and had fallen off, exposing corroded steel reinforcement— an ongoing maintenance and health and safety problem; repairs were undertaken in 2001 and 2005 but the repairs were themselves in poor condition; the lightweight mortar failed to bind and was spalling in areas. 

Exposed concrete window mullions spalling throughout the block facade

The walls of the buildings had no thermal insulation; the existing windows were clear float single glazed metal Crittall windows. Classrooms are located behind the east and south elevations; the rooms suffered from solar gain and were hot and uncomfortable in summer— a situation exacerbated in the IT suites where air-conditioning was required to counteract the additional heat gained from IT equipment ( in these rooms, internal blinds on the windows were almost permanently left down to try and reduce heat gain and solar glare from the afternoon sun ). In winter, the building did not retain heat well and the school’s energy bills were high. 

Exposed reinforcement to the balconies

Clays were commissioned by the school to carry out concrete repairs and refurbish the façade of the main and science blocks; following the disappointment of being dropped from the BSF programme in 2010, the school wanted a fresh new look for the school buildings to send a positive message to the school community. Clays also carried out a feasibility study that demonstrated that extending the blocks to create a new Sixth Form Centre would be uneconomic— extension work would bear the extra-over costs of temporary accommodation for 16 classrooms; the original buildings had not been designed for disproportionate collapse and the cost of structural work for any extension would be disproportionate to the net area gain. 

Turning our attention to the façade works, a heat gain and natural ventilation analysis was carried out using Classcool and Classvent software. 

Clays developed a refurbishment strategy that involved:

 • The removal of all horizontal concrete window transoms and repair and protection of exposed oxidised metal reinforcement to the balconies. 

• Reducing the number of windows to the IT suites to the minimum required for natural ventilation to BB101. Solid composite panels rather than clear glass panes were specified on some of the windows in order to further reduce heat gain and solar glare. 

• Replacing the existing Crittall windows with double-glazed aluminium windows designed to be fixed in front of the exposed concrete columns, thereby protecting the reinforced concrete elements from the weather, reducing cold bridging, interstitial condensation and further concrete failure. The new windows had a maximum U-value of 1.8 W/m2K and were doubled-glazed with an outer pane of low E glass with a solar transmittance of 0.4 or below— resulting in a 52% reduction in solar transmittance without significant loss of daylight transmittance. 

• Replacing the existing ‘fish-scale’ tile cladding with rainscreen cladding ( cedar on the east façade and Trespa on the west façade— which is in shadow and not suitable for timber ) to achieve a maximum U-value of 0.28 W/m2K. 

The contract, managed by Clays, was let for tender and completed, within a tight budget, in 12 weeks in time for the 2012-2013 academic year. 

In the process, 1,958Lm of defective concrete and cold bridging have been encased / removed. The rooms now perform significantly better which will prove beneficial to running costs and comfort— in summer, blinds are now left up and lights left off. The school is very happy with the look of the refurbished blocks. 

The main teaching block after refurbishment

View of the refurbished teaching block

Image/s: Before images by Clay, after images by Dilip Hirani