Last year’s Interbuild show in Johannesburg provided an innovative platform to showcase the many and varied attributes of timber in construction with the erection, within one of the Exhibition halls, of an actual, full-scale, timber frame home.
The project arose from an approach by the Institute of Timber Frame Builders (ITFB) to the exhibition organisors and it was proposed that a timber framed home component would bring a fresh dimension to this popular, long standing, annual event.
The proposal included a joint venture with the Wood Foundation and the Institute of Timber Construction (ITC) so that all aspects of timber could be exhibited in keeping with the objectives of these organisations.
A working group was formed to put the project into motion, including Werner Slabbert of Eco Log Homes, Gerard Busse of Arch Wood Protection, Jenny de Waal of the ITFB, Samantha Beresford of York Timbers and Alan MacGregor of Flagship Communications.
The fundamental intent of the project was to incorporate a variety of timber finishes and other non timber products to underline the versatility of timber in construction and to re-generate awareness across a wide spectrum of potential markets and stakeholders of what this tried a tested natural material continues to offer in today’s competitive construction environment.
Indeed, the Wood Foundation House as it fondly became known, demonstrated in a very tangible way, timber’s unbeatably low carbon ‘footprint’ in production, the fact that it’s derived from renewable resources, its durability, strength, flexibility, excellent thermal and acoustic qualities, it lends itself to speedy construction at competitive prices and it’s unmatched beauty.
Numerous stakeholders in the timber sector at large stepped up to the plate as it were, as sponsors of the house, in terms of materials, expertise or time, underlining the fresh spirit of commitment that is sweeping this time honoured industry.
Notable among these individuals and companies was architect Jacques Cronje who provided his services for the design of the home and Werner Slabbert, owner of Eco Log Homes, who undertook the heavy responsibility of the construction work (see the full list of sponsors below).
The project was extremely fast tracked with the build of the house commencing on August 16 and with the requirement that it be completed on site in time for the opening of the exhibition on Tuesday September 7.
The various components were built in panels for easy re-erection at the show and these were duly transported to Nasrec on September 3 and re-built inside the exhibition hall in what proved to be a remarkable team effort.
The fully functional house that emerged virtually overnight included a kitchen, lounge, bedroom, en-suite bathroom and decking. The result drew a great deal of favourable comment and interest from visitors from many quarters, suggesting that the exhibit’s objectives have indeed been met and that the foundations have been laid for the way forward.
PROFILING THE INTERBUILD HOUSE
Basic structural methods
The structure used a post and beam method which is traditionally applied when constructing solid log homes.
This facilitated the various panels which were all constructed in different ways i.e. Solid log tongue and groove, Solid log groove and biscuit, timber frame and each panel was clad in a different type of cladding.
The floor structure was constructed with a 50 x 152mm box frame system which had a 18mm CCA treated shutterply board as a sub floor to facilitate the show floor environment.
Normally a floor structure would be constructed with 76mm x 228mm bearers on posts and 38 x 228mm floor joists. The roof construction was constructed in two different basic styles namely, trusses and beam and rafter. This was to showcase conventional roofing with flat ceilings and cavity roofing showcasing roof lining ceilings.
Types of timber used
99% of timber used was SA Pine made up of Laminated posts/beams, solid interlocking logs, log profile cladding in various different thickness, cabin board, pine decking, saligna decking, pine shutter ply boarding, pine tongue and groove and bamboo flooring.
Solid logs, interlocking log systems, Log profile cladding, cabin board, fibre cement wood grain plank (Vermont plank or Handy plank) in various different widths.
Tanalised C (CCA) and Vacsol (TBTN).
Other materials used
UFCC fibre cement T&G boards (internal Kitchen walls), UFCC Fibre cement wood grain planks (Exterior wall cladding), Gypsum ceiling board, 15mm Water resistant Gypsum board(shower and loo), 15mm fire stop Gypsum board, Asphalt shingles(Roof), OSB boarding (Roof), Meranti sliding doors (bedroom/ lounge/Kitchen) Meranti windows(kitchen, bedroom,loo), 38mm x 114mm CCA treated timber was used for the framing of the wall panels, decking clips were used to fasten the decking planks, CCA treated timber was used for the balastrading on the decking.
Time taken to completion
2 weeks from time of materials delivered to time of show commencement.
Werner Slabbert/ and working group comprising Gerard Busse of Arch Wood Protection, Alan MacGregor, Jenny de Waal,
Co-ordinating delivery and assembly of the various components – the main challenge was securing all materials from sponsors and materials being delivered timeously. The entire house had to be built on site and then dismantled, transported and re-erected at the show within a 3 day build up period, crew worked 247. Due to the fact that the house was built in panels for ease of erection the puzzle could only begin once all the pieces were in place. Another challenge was that the show floor was not level and this was not expected. This meant that the entire house floor structure needed to be spaced to get a level floor on the house.
Benefits proved by the exercise
Bringing together all the key role players in the wood industry i.e TWF, exposure of both the TWF and the ITFB, creating a general awareness to the public visiting the house that timber construction is a alternative form of construction to the conventional methods i.e. brick and mortar.
Each crew member had a specific skill that was required in the build of this house, unlike most brick construction labour components who are generally fairly unskilled, every single member of the carpentry team is highly skilled in their field of carpentry.
Costs per square metre
Between R5000-00 and R6000-00 psqm which is no cheaper than conventional building methods. However, if you compare conventional building methods on sloping sites or clay soil condition sites a timber homes definitely becomes cheaper than conventional brick and motor.
Isover Vapour Membranes – St.Gobain
Isover Cavity Bats – St.Gobain
Fibreglass Shower Cubicle- Knysna Fibreglass
Structural Timber- York
Gysum Ceiling Board – St Gobain
Firestop Gypsum Board- St.Gobain
Waterproof Gypsum Board –St. Gobain
SA Pine Log Profile – D & A Timbers
Ashphalt Shingle System – Global Innovative Building Systems
TBTN Laminated Beams- Cape Sawmills
CCA Log Profile Cladding- AG Muller
CCA Roof Trusses, rafters and laminated beams- Manny’s Roofing
Roof Engineering design- Mitek
Paint Exterior/Interior – Olympia Paints
Furniture – Woodbender
Exterior and Internal Varnish – Rystix
Wood Grain Fibre Cement board – UFCC
Meranti sliding doors – Van Acht
TBTN Solid Log Interlocking Panel – Timbaclad Knysna
CCA Treated Groove and Biscuit Panel – Timbaclad Knysna
CCA Treated Pine Cabin Board – AG Muller
Windows – Van Acht
CCA Lamintated Posts –White River Sawmills
TBTN laminated posts – Cape Sawmills
CCA Pine decking – Noags Market
Saligna decking- Noags Market
Decking Clips – Pretoria Pole Treaters.
St Gobain Construction Company
AG Muller Sawmills