Project: Renovation of a Grade II Listed Farmhouse and New Build Barn.
Main Challenges: Combination of ‘old’ and ‘new’, appropriate use of materials, airtightness.
I am currently working on a site in Oxfordshire which comprises of the total renovation to an imposing Grade II listed Georgian Farmhouse which had been uninhabited for many years and was virtually derelict. The farmhouse is also having two large extensions that the architects have designed in a fairly radical contemporary style to totally contrast with the old traditional form of the farmhouse.
On the same site a new “barn” style building is being constructed which will be used as a cookery school. This building is being constructed in timber frame, wrapped around a structural steel curved roof, portal frame and clad on the outside with larch planks and a corrugated galvanised sheet roof. Large windows and doors will complete the “converted barn” look that the architects have designed.
There will be a home office building of timber frame construction and lots of hard and soft-scaping, including swimming pool and tennis court.
Another rather interesting aspect is that since the ground conditions are mainly all clay based beneath the top-soil, groundwater was a serious issue which resulted in the need for a bore hole going down some 130 meters to be sunk, to allow the rainwater system for buildings and ground to drain away.
The works are being divided insomuch as the farmhouse works are being completed by a main contractor builder and the remainder by client and myself using sub-contractors. I was originally invited to be involved because the works to the farmhouse were proving to be rather challenging for the builder, so my experience with works to listed buildings and sites of this size generally, along with the plans for the remainder of the site could be utilised. I am therefore employed in both roles of Build Consultant and Project Manager on the same site.
To date, the Farmhouse is at 2nd fix stage, previously having had most of the roof structure replaced, with many of the internal floors also renewed including the ground floor (originally tiles on dirt) which required tanking since some of the floor levels were actually below ground. Ground levels could not be reduced since the building has no foundations as such and despite certain areas being underpinned, there was a structural need for ground levels to remain. All external walls are insulated with fibre insulation boards and plastered with lime plaster. Some windows were just about salvageable but most had to be remade, all to exacting design to satisfy the local conservation officer, as were just about any works to this part of the building. Some external walls were re-built and the entire building re-pointed with lime putty.In the past couple of weeks, windows have been fitted including the Alu-clad large high performing windows, curtain walling and doors to the two extensions.
Airtightness detailing and energy performance has been a major consideration throughout the entire building.Elsewhere on the site Foundations etc are in place for the barn awaiting the structural steel frame which is due in four weeks’ time. Coordinating the structural steel frame with the timber frame building has been a challenge. The client particularly wants the building to look much older than it is, so all steelwork will be exposed internally with the timber frame passing around the outside. Many of the internal wall sufaces will be clad with reclaimed softwood planking.
This all sounds very straight forward but Structural engineer, Timber Frame designer, Architect, Ground-worker and Steel fabricator all had to be singing from the same sheet, with myself orchestrating the performance.
As of yesterday, all is signed off and ready for manufacture. The usual timber frame design elements had to be agreed to ensure window openings, floor levels etc were correct. My extensive knowledge of timber frame construction has been beneficial especially with certain detailing such as the curved roof.
Groundworks, including the Sewer treatment plant are progressing well and the bore hole drillers arrived on site yesterday afternoon. Unbelievably, they anticipate drilling down to 60 – 70 metres today!
Since certain ground waters such as the outfall from the treatment plant (although virtually drinkable) and any tarmac run off cannot go into the bore hole, a large pond is being dug for the remaining surface water drainage. Foundations etc and services are constructed for the Home Office building and general ground sculpting has commenced.
We are just about to enter into what will be a very busy few months!