It is acknowledged that work to over clad Unit 69 would need to be carried out in phases. For the purpose of establishing estimated costs the following phasing has been assumed:-
Phase A
South elevation ground and first floors (S1 on elevation key) and West elevation ground and first floors (W1, W10, N2 (part), S6 and N7 on elevation key).
Approximate overall wall area 1540m2.
Phase B
North elevation ground floor only (N1 on elevation key) and East elevation ground and first floors (E1, N3, S4, N2 (part) and S5 (part) on elevation key)..
Approximate overall wall area 669m2.
Phase C
Internal courtyards of Unit 69 ground and first floors (N8, S8, W11, E10, N2 (part), S5 (part), W3, E7, W2, E6, W9, E2, W12, E3 S3, N4, W4, E4, S2, N5, W5, E11, S7, N6, W7, E5, W6 and E12 on elevation key).
Approximate overall wall area 2363m2.
A summary of the estimated costs broken down on a phase/phase basis is given in Appendix G. The estimated costs are based on current market rates assuming the use of a standard form of building contract. Allowances for professional fees and VAT are indicated against each option.
In order to mitigate Optimism Bias the caveats stated earlier in this report relating to the possible disturbance of asbestos-based products, potential deterioration of steel columns and the possibility that the existing steel columns will not be capable of supporting the over cladding system, have been the subject of a simple risk assessment as follows:-
| Description | Potential Cost |
Assessed Risk |
Adjusted Cost |
| Disturbance of asbestos | £125,000 |
20% |
£25,000 |
| Deterioration of steel columns | £50,000 |
10% |
£5,000 |
| Capacity of existing steel columns | £100,000 |
10% |
£10,000 |
| Total Risk Allowance | £40,000 |
||
The resulting addition of £50,000 is inclusive of professional fees and VAT, and is shown on the summary of estimated costs for each option.
No allowance has been made for decanting. A table indicating the estimated construction period for each phase of each option is also included in Appendix G.
The approximate gross internal floor area of Unit 69 is 10,800m2. The estimated cost for complete rebuild of the unit on a different location on the Stoke Mandeville site is likely to be in the order of £30m – £35m inclusive of demolition of Unit 69 on completion of the new building, professional fees and VAT. The element of this anticipated cost for demolition is £600,000 including an allowance of £250,000 for removal of asbestos (based on data obtained from a contractor who has recently dealt with demolition of Oxford Method buildings on The Battle Hospital site in Reading).
In addition to the four options to over clad Unit 69 and an option to replace the facilities at a different location on the site (see above), the “do nothing” and “do the minimum” options have also been considered. A “do the minimum” approach has already been taken to enable Unit 69 to continue functioning and it is now believed that this ad hoc approach is no longer viable particularly given the information learnt from the project to reclad the Opthalmic Unit. It is understood that the deterioration of the panels is caused by rusting from within the panels and therefore recoating of the panels is of no benefit. In addition many windows also require replacement.
As a temporary measure, the entire Unit could be “cocooned” with a scaffold structure supporting an independent sheeting as a rainscreen. This is thought to be totally unacceptable due to the aesthetic impact of such a structure and also as it would effectively block light from all of the windows.
In Appendix H net present cost calculations are shown for over cladding (using an approximate average of the four cladding options shown in Appendix G) and for the rebuilding of Unit 69. The over cladding option includes a cost for replacement of Unit 69 after 10 years which is believed to be its current life. An annual allowance of £50,000 has been shown for ongoing emergency maintenance. The approximate net present costs are summarised as follows:
| Commence planning now and replace unit in 4 years | £31.35m |
| Over clad now and replace unit in 10 years | £27.75m |
©2004 Oxford Method Royalties Management Group