6 Sidmouth Avenue is the remodelling of an existing old Oranjezicht home. Oranjezicht is an old suburb in the Cape Town city bowl, situated on the slopes of Table Mountain.
Most of these old homes face north, look over the city below and have imposing but spectacular mountain views at their rears.
The existing old home was a typical 50’s ‘box’ type double story home but lacking real architectural merit. The brief called for a complete renovation and make-over. This involved adding a floor for a new main bedroom suite as well as gutting, re-planning and enlarging the living and kitchen areas on the lower levels. In addition, the landscape was reshaped with new outside living areas. Only what now is the middle level was retained in a planning sense.
The existing kitchen (at the rear) had to be opened to take advantage of the mountain views. By introducing a 1x8m steel girder weighing about a ton were we able to support the weight of the structure above and bring the views into the kitchen. This girder had to be craned over the house to get it in place. A new steel cranked roof, forming a kitchen living space was clipped onto the front of this girder. The cranked angle of this roof allowed unimpeded views into the kitchen and maximized the views from its adjacent living space. This room, in turn, opens up onto the pool area at the rear of the property.
The use of reversed IBR profile cladding on the verticals was used as a device to tie in the new roof conversion with the old walls below. The result is a homogenous blend of the old and new, pulling the whole design together. We wanted to avoid the extension looking like an afterthought. One other innovation was the use of powder-coated steel window boxes which project from the façade. These have a dual role of being the main window flashing element in the lightweight walls and the finishing gasket against the IBR sheeting. This was used in lieu of the standard wide steel flat profile normally used around sheet façade openings.
Due to the old structure, there was uncertainty around the bearing capacity of the old walls, and it was decided very early on in the project to propose LSF. Many existing and critical ground floor support walls and beams were removed. To compensate, hot rolled structural steel elements had to be introduced under the existing first-floor slabs. The lightweight nature of LSF above was critical to the success of these supports. The nature of the steel cladding also lent itself perfectly to the use of LSF. A further challenge was to connect and combine the LSF roof elements with some long span timber laminated beams which spanned the entire length (gable to gable) of the upper level.
I was already familiar with LSF technology, having used it on two prior projects. The prior experience I gained using LSF had introduced me to the key players in the industry, namely the structural engineer and the LSF contractor. I had also worked with the main contractor so that there was a familiarity in the professional team, and we had a good working relationship. Unfortunately, the LSF contractor ran into financial difficulty early on during the erection of the LSF. He abandoned the project leaving the client and the professional team to pick up the pieces. Our main challenge was that the budget did not allow us to re-tender the LSF and cladding and so the main contractor, client and myself project-managed the LSF. One of the LSF Contractor’s former erectors, a Zimbabwean named Para Chimimba, was brought in to complete the works. We, therefore, lost the time-saving benefits of using LSF. The project was delayed causing enormous financial pressure for the client and created a challenging working environment. Despite this challenge, we managed to pull it off – and the proof is in the result.
|LSFB / LIGHT STEEL FRAME BUILDING WORK|
|Completion date of LSFB work||March 2017|
|Completion date of full project||January/February 2018|
|Tons of LSF used||3 Tons|
|Profiles used||89mm .75 lip channel
|Completion date of cladding||June 2017|
|Cladding profile/ type used||IBR – inverted|
|Nominator||Chris Wood Architect|
|Architect||Chris Wood Architect|
|Structural Engineer||By Design Consulting Eng|
|Main Contractor||Arba Construction|
|Steelwork Contractor||Arba Construction|
|Cladding Manufacturer||Youngman Roofing|
|Cladding Supplier||Youngman Roofing|