This grade 2* listed building at St Michaels Manor Hotel in Hertfordshire had an existing ‘Machin style’ conservatory. Our client requested the old conservatory to be taken down and replaced with a larger structure that had better insulation and was more sympathetic to the host building. The customer had previously visited one of our restaurant-orangeries at the Phyllis Court Club at Henley-on-Thames and was impressed with the quality and ambience of the space created.
The client was clear that the new building had to be at least 7m deep (2.5m deeper than the existing structure) to add more covers, although the width would remain the same. Making the new extension much deeper than the old would require a complete rebuild, including new foundations and the walls that enclose the store room below. Our client requested a completely managed project which we provided with what we call our ‘full turn key service’.
We discussed the benefits of an Orangery style and the possibility of three lanterns to reduce the height and the client liked this approach. Once the final detailing was discussed an order was placed in Dec 2009 and a date fixed for us to start works in January 2011 with a 3 month window to complete the works.
The initial design was very similar to the one actually built and only the left side feature Gable was removed during the planning process, which was far from straightforward, requiring a great deal of negotiation with the local authority especially the conservation department.
Following the planning process we carried out an in depth site survey to provide key information to our engineers and drawing office to enable the working drawings and structural calculations to be produced. We worked closely with our clients interior designers to ensure that the air conditioning, lighting, heating and sound system could be incorporated within the structure without compromising its design.
David Salisbury were contracted to complete the works within 13 weeks and starting the project at the worst possible time of the year was going to be a challenge.
Our installation team produced and agreed a program of works with the client, prior to works commencing and updated them with progress throughout the project. The 1st week concentrated on setting up the site, isolating existing services and demolishing the existing structure.
It quickly became apparent that the existing foundations were constructed with steel reinforced concrete and our contractors had to bring in specialist breaking equipment. With this unforeseen element of work and the poor weather conditions we fell behind schedule. The next few weeks brought favourable weather and with working additional hours, we quickly regained program. We liaised with hotel staff every daily to ensure that noise levels were kept to a minimum so not to disturb guests.
The ground works were extensive as approximately 140 tonnes of spoil had to be cleared from site to construct the foundations and the lower ground level store. Once complete, the walls constructed with a dense concrete backing block, faced up with brick and natural flint panels went up quickly, ready to receive the block and beam floor. The walls were then built to the finished height, ready for the orangery frame.
An 8m x 3m opening had to created in the back wall of the hotel and the block and beam floor gave us a platform to work from whilst propping the wall and inserting the 6 tonnes of steel required to support the existing building. The orangery frame went up within 1 week and the laminated beams were lifted into position and the insulated roof deck added. This process took a further 2 weeks. Shortly after this the lanterns were installed and the orangery made watertight.
The internal fit-out began with our electricians installing a digital mood lighting system, ring circuits and automatic roof light openers, with rain sensors. The existing heating system was upgraded and extended into the new orangery and an air conditioning system was installed. A rapid hardening screed was laid in order to reduce drying out times and bring the installation of the floor finishes forward. Throughout the duration of the project we carried out quality checks to ensure that when complete we had minimal snagging. We completed and handed over the orangery, ahead of program, allowing our client to open two weeks early. Our customer was extremely pleased with the finished product and is more than happy to recommend us to any future clients.