St Johann

Modul8 was built in Gauteng in a controlled environment & then transported to Lesotho & placed on a prepared soil platform. A steel ring beam at the top & bottom, together with square steel posts act as a rigid frame which can be picked up from the top to load on a truck, transport to site & dropped off on a pre-prepared foundation.

150dia Round Tubular Steel columns with 32dia tubular steel cross bracing was selected for the foundations. The columns were prepared (manufactured) in the factory off-site, and the bolted to a rock plate covering the entire stand, with 4 of M16 threaded rods, fastened to the rock plate with epoxy which can harden under water.

The roof structure was also pre-manufactured in the factory in Gauteng, complete with double glazing & lifting brackets, in order to have minimal work to be done in the harsh weather conditions on site. The roof structure was placed on the Modul8 units by the same crane mounted on the truck horse, after which the 90mm thick PU foam SIPs were placed on the frames on site as an all-in-one roof covering, ceiling & insulation. A neat rectangular angle serves as finishing to the edges of the roof SIPs as well as drip to the lower end of the roof.

The roof/wall glass & steel structure act a unit & is cross-braced through the use of Structural silicon between the double glazing & steel frame as well as the use of the roof SIPs

A corner niche was also manufactured in the factory in Gauteng, trucked to site together with the Modul8 units & placed in position by the same crane mounted on the horse of the truck. The corner niche can also be picked up from the top and is bolted straight to the corner of the kid’s bedroom.

A cantilever ‘landing’ grid was chosen for the front door, only held in place by hinging it to the short end of the Modul8 bottom ring beam & a 32dia round tube profile ‘arm’ to hold it in the horizontal position. This grid helps to keep mud & snow out of the ski chalet, as mud is dropped through the grid when stepping on it before entering the front door.

Green building rating/ environmental or sustainability considerations

Many environmental & sustainable considerations were employed as are shown in Point 3 & 4 (Please read point 3 & 4 together with this section)

Because the Modul8 units are manufactured off-site, there is no damage to the site or the surroundings during the construction process, as no construction takes place on site accept for the foundations. The foundations are also of a lesser scale as the inherent strength of the Modul8 units and the shipping containers are already built into their structure, needed when transporting the units, thus the foundations do not have to be that strong.

 

As the building is pre-manufactured off-site & then brought to site, the buildings can also be taken away again & the site can be totally rehabilitated.

As the Modul8 units are modular, materials were optimised to their modular size, resulting in very little to no cutting, resulting in no waste of materials, labour, equipment, tools or time.

All Modul8 units are ‘properly’ insulated, made in a controlled environment with strict quality control procedures and of high-quality materials & finishes, resulting in less heating- & cooling costs, as well as less maintenance

Low maintenance to no maintenance materials were chosen to reduce maintenance costs in the long run, as well as reducing the materials, cleaning & maintaining agents which will go with maintaining a building

Because the Modul8 units are movable (transportable), they can be reused or up-scaled when they have reached the limit of their current use, e.g. if not required as a ski chalet at Afriski anymore, it can be moved to the coast as a beach cabana.

A Modul8 building can be ordered to be totally off-the-grid, as it can contain its own solar/wind/gas power generation and/or water heating mechanisms in order for it to be totally self-sustainable and/or in hard-to-reach and un-serviced locations.

Solar water heating backed up with gas, is used for domestic water heating as well as for hydronic underfloor heating.

The ski chalet is lifted off the ground by placing it on the round tubular steel columns, for a few reasons:

1 There are more than 400 natural water springs on the resort, of which two flow from underneath the position of the ski chalet. By lifting the chalet above the ground, the flow of the water is not restricted to flow downhill and cause damage to the structure.

2 If or when the ski chalet is moved to a new location, for instance as a retirement cabin at the coast, the site can be easily rehabilitated to its original state. 

Many years of design, various prototypes, extensive structural-, wind- & fire tests were done to get to the current design model:

Steel, in various forms e.g. Light Gauge Steel Frames, Hot rolled steel & cold rolled steel, galvanized bent plate, SIPs, etc. was chosen for its many positive attributes like strength-to-weight ratio, flexibility, cost-to-strength ration, durability, low maintenance, etc.

Many hours & details went into designing a structure which can be manufactured & assembled in a factory, can be lifted from the top, (instead of through the frame or with belts under the frame), is under 3 tons in weight in order for ‘standard’ truck cranes to lift the Modul8 units onto a truck & off again on site, flexible enough to withstand the current South African (and rest of Africa) road conditions on a truck, and last many decades on site to be even moved again at a later stage.

Modul8 is currently designed to be stacked 3 stories high, but with nominal steel sizes or wall thickness increases, this can be increased to many more stories.

Usually, 1-3 days on site are enough to place the Modul8 units, connect them to each other, waterproof them & connect the services to the units if necessary.

Weight was a major consideration when designing modular units, as well as the lifting method, as both have an influence on the transport of the units: It was thus critical to keep the weight lo, while retaining the strength & flexibility of the units.

Strey Architects paid a lot of attention to designing for the maximum allowed size to fit on a truck withouta police escort, as well as to stick to standard sizes of materials

The Afriski Backpackers Lodge

The original Backpackers at Afriski was built with shipping containers as they seemed appropriate for the low cost, weather proof, indestructible and quick accommodation qualities at the time.

With the extended & reworked Backpackers factory manufactured modular units called Modul8 was built in Gauteng in a controlled environment & then transported to Lesotho & placed on a prepared soil platform. A steel ring beam at the top & bottom, together with square steel posts act as a rigid frame which can be picked up from the top to load on a truck, transport to site & dropped off on a pre-prepared foundation (a soil mattress platform in this case). The smallest possible cellular beams were utilised in the floors to support light weight textile concrete, to save weight & to thread services through the holes of the cellular beams

Round tubular steel profiles were used as ‘tree’ columns in the courtyard, supporting lipped channel purlins to carry the relatively large span (for the element sizes used) over the courtyard in order to ‘feel’ like or simulate a ‘picnic’ area under ‘trees’ on a ‘lawn’ (It was an interesting exercise as the one will not stand without the other (‘trees’ & purlins) and the roof sheeting serves as cross bracing)

Rectangular & square tubes were utilised for the double glazed roof & wall structure facing the ski slope, as it was easier to pre-manufacture & test erect in a factory environment and could easily be bolted together on site in a relatively short period in adverse snowy conditions. The double glazing lets in sun & light during the day which heats the concrete floor which in turn emits the heat at night, gained during the day. The roof/wall glass & steel structure act a unit & is cross braced through the use of Structural silicon between the double glazing & steel frame  

The combination (Hybrid) of materials & building methods utilised makes this project unique:

The Modul8 units (6 off) used for the project are a vast improvement on ‘traditional’ shipping containers. The original Backpackers’ shipping containers were reused, although flawed, as they are too narrow to accommodate & be practical for much more than small bedrooms or bathing ablutions. Also, if you cut holes in shipping containers you take away their inherent strength and need to reinforce the frame with more steel, which make it actually very uneconomical.

Modul8 pre-manufactured, modular units were design & manufactured off site (in a factory in Gauteng) to improve on all the inherent flaws of shipping containers but still utilise all the advantages of shipping containers. They insulated, wider, higher, longer, more flexible & lighter than shipping containers. They can be flat packed and transported in numbers on one truck if assembled on site. These were pre-assembled, together with the courtyard roof & glass roof/wall system in a factory in Gauteng, (without the shipping container units which were already utilised on site for some years), before being disassembled & transported to site for placement & completing the project. 

A simple & cost effective IBR roof was screwed to lipped channel purlins (a very light structure was designed to be handled by manpower only), and the sods which used to cover the site & was placed to one side for re-use, was place on the roof sheets to help act as insulation (and greenery), together with insulation board, for the roof. Because the entire envelope is insulated, heat cannot escape easily. This was critical as sometimes temperatures of -20 C are reached in winter.

A 20’ shipping container was also utilised as a hot water storage tank. Polyuria was used to waterproof the inside of the container, and board insulation for thermal proofing, in order to use the container to store heat generated through arrays of vacuum tubes on the roof to heat water. The hot water is then used in the ablutions as well as to pump through the concrete floors to create a fly wheel effect of heat being released during the cold nights all year round, (and days during the winter).

Zink/Aluminium panels (Zincalume Structural Insulated Panels) were used to the Modul8 units around the covered interior courtyard for its aesthetic appearance, strength & longevity.

Green building rating/ environmental or sustainability considerations

Because the Modul8 units are manufactured off site, there is no damage to the site or the surroundings during the construction process, as no construction takes place on site accept for the foundations. The foundations are also of a lesser scale as the inherent strength of the Modul8 units and the shipping containers are already build into their structure, needed when transporting the units, thus the foundations do not have to be that strong.

As the building is pre-manufactured off site & then brought to site, the buildings can also be taken away again & the site can be totally rehabilitated.

As the Modul8 units are modular, materials were optimised to their modular size, resulting in very little to no cutting, resulting in no waste of materials, labour, equipment, tools or time.

All Modul8 units are ‘properly’ insulated, made in a controlled environment with strict quality control procedures and of high quality materials & finishes, resulting in less heating- & cooling costs, as well as less maintenance

Low maintenance to no maintenance materials were chosen to reduce maintenance costs in the long run, as well as reducing the materials, cleaning & maintaining agents which will go with maintaining a building

Because the Modul8 units are movable (transportable), they can be reused or up-scaled when they have reached the limit of their current use, e.g. if not required as a ski chalet at Afriski anymore, it can be moved to the coast as a beach cabana.

A Modul8 building can be ordered to be totally off-the-grid, as it can contain its own solar/wind/gas power generation and/or water heating mechanisms in order for it to be totally self-sustainable and/or in hard-to-reach and un-serviced locations.

Many years of design, various prototypes, extensive structural-, wind- & fire tests were done to get to the current design model:

Steel, in various forms e.g. Light Gauge Steel Frames, Hot rolled steel & cold rolled steel, galvanised bent plate, SIPs, etc. was chosen for its many positive attributes like strength-to-weight ratio, flexibility, cost-to-strength ration, durability, low maintenance, etc.

Many hours & details went into designing a structure which can be manufactured & assembled in a factory, can be lifted from the top, (instead of through the frame or with belts under the frame), is under 3 tons in weight in order for ‘standard’ truck cranes to lift the Modul8 units onto a truck & off again on site, flexible enough to withstand the current South African (and rest of Africa) road conditions on a truck, and last many decades on site to be even moved again at a later stage.

Modul8 is currently designed to be stacked 3 stories high, but with nominal steel sizes or wall thickness increases, this can be increased to many more stories.

Usually 1-3 days on sire are enough to place the Modul8 units, connect them to each other, waterproof them & connect the services to the units if necessary.

Weight was a major consideration when designing modular units, as well as the lifting method, as both have an influence on the transport of the units: It was thus critical to keep the weight low, while retaining the strength & flexibility of the units.

Strey Architects paid a lot of attention to designing for the maximum allowed size to fit on a truck without police escort, as well as to stick to standard sizes of materials.

The biggest challenge with Afriski is the inclement weather conditions, the altitude & the location of the site. Because of the altitude people inherently move & work slower. Because Afriski is located in a bowl, (less sun means more snow), the days are actually also shorter as the sun rises later over the East ridge & sets earlier over the West ridge. There are thus less daylight hours & the temperatures drop steeply when the sun disappears behind the Western ridge. Four seasons during the day is common, and it is known to snow in December & in April every year (there are weather records for the past 50 years). The distance of the site (Afriski) to the nearest town with most type of hardware & building supplies is at least a day (round trip) away, so one cannot ‘forget’ anything or construction will stand still.

Developing a pre-manufactured building system, which is built in a controlled factory environment have the following advantages, apart from the ones mentioned in Point 2-8:

  • Workers return to their own accommodation each night so there is no need to house & feed the construction workers
  • The weather does not influence the building process
  • Better quality control can be adhered to
  • Less to no waste and no waste needs to be removed  from site
  • Longer (normal) working days & working hours can be adhered to

The innovative use of several different types of steel products, and the combination thereof creating a hybrid & practical solution to the challenge, is noteworthy

Midax House Zinkwazi Beach

The Midax House Zinkwazi Beach project entailed the addition of a second level to an existing house situated on the beachfront.

Founding conditions were basically beach sand and the addition, therefore, had serious limitations in structural weight.  In addition, the architecture required clear view lines, large open plan areas and quirky overhanging rooms, all which required large spans and cantilever structures.  The design had to be exactly matched to the existing ground floor brickwork structure.

This was achieved by using a duplex coated structural steel skeleton structure, lightweight roof, and floor, as well as some composite material cladding.

The following aspects of the project make this an exceptional project and use of structural steel:

  • The structural steel skeleton and lightweight cladding allowed acceptable foundation loading and hence, in essence, made it possible to affect the build.
  • The structural steel allowed the key architectural elements of open plan areas, uninterrupted views, quirky overhanging rooms, and modern lines to be built.
  • The steel structure saved considerable construction time and the use of CAD technology and modern laser measurement techniques resulted in a very successful build on to a complex shape existing structure.
  • The property is situated in an environmentally sensitive area (within 100m of the highwater mark) and the steel construction allowed for a clean and neat build process with no damage to protected milkwood trees.
  • The structural steel skeleton allowed for proper services planning in a “hollow floor” and also for the integration of add-ons such as facia mountings, gutters, and glass balustrades.

Midax Investments Pty Ltd acquired a beachfront property known as Magai Drive 45 in Zinkwazi Beach in June 2013.

At the time the 1970’s designed house was somewhat run down, but the location right on the beach and the sea views offered warranted the investment.

The plan at the time was to add onto the house so as to create a beach house where a 3 generation family could holiday together. The property is however located within the environmentally sensitive area within 100m of the high water mark.  As such footprint extensions were, at the time, limited to 50sq meters. This forced planning to consider the addition of a second level.  In addition, the existing cement tile roof was very dilapidated and as it was considered to be unsafe, the plan for replacing the very heavy roof (some 20tonnes) with a second level living area became very appealing.

Structural engineer Rob Young who, at the time was involved in another Zinkwazi project (the 2015 winner) was approached to act as consulting engineer on the re-build of 45 Magai.  Following soil testing and inspection of existing foundations, Rob advised that it would be possible to add a second level provided that the design stayed within 25-30 odd tonnes of weight on the existing foundations.

Architect David Mealin, a Zinkwazi resident, was appointed to design the largely “new” house.

He produced a very modern concept which maximised the views, contained large open plan living areas and some quirky features such as overhanging “glass box” bathrooms.  He also incorporated the client’s wish for a large veranda at ground level, the roof of which doubled as a large (100sqm) deck for the upper levels.

The structural engineers were therefore faced with the following challenges:

  • Engineering a reasonably lightweight structure which would allow the uninterrupted sea views, large open plan areas and quirky design elements
  • Engineering a very corrosion resistant structure capable of withstanding the highly corrosive KZN North coast environment
  • Fitting the structure to a fairly complex existing ground floor wall layout.

Rob Young suggested a steel structure with a light-weight wooden floor and light-weight aluminium roof for the new upper level.

At this point, it must be pointed out that Piet Coetzer, the director of Midax Investments, is also a major shareholder in the Structa Group of Companies, which is one of the larger manufacturers of steel structures in South Africa.  Piet has often advocated the use of more steel in buildings in South Africa and here he was presented with an opportunity to practice what he had been preaching. Being a structural engineer himself he duly accepted the challenge and through Structa Konsult, he participated in the design of the staircase and bathroom boxes, while Rob Young designed the primary structures.

In essence, the structure consisted of the following elements:

  • A concrete ring beam cast onto the existing ground floor walls at the rear of the house
  • Fabricated girders spanning window openings on the seaward side of the building and serving as the seaward portion of the ring beam
  • An array of I-beam floor beams spanning from the concrete ring beam (where they are anchored), cantilevering over the forward fabricated steel girders to form the deck
  • Roof support columns
  • I-beam front and rear roof carrier beams
  • Wing style roof consisting of pointed I section trusses and lip channel purlins
  • Thin-skinned box girder 3CR12 sections forming overhanging bathroom structures
  • GRP “sandwich” side walls closing off overhanging bathroom boxes
  • A “floating” staircase
  • A mezzanine portion of the floor suspended from the roof to give clear view lines In the entrance

Most of the seaward fabricated beams were not clad externally so as to express the nature of the structure.  Where cladding was used the following materials were employed:

  • Plasterboard on internal surfaces
  • Brick walls on the rear wall
  • Brick infill on some seaward fabricated girders
  • Nutec board

The structure was detailed using the TEKLA system.  This was performed by C.I.S Engineering (a Structa Group subsidiary), who was appointed as manufacturer.  TEKLA details were used as direct input for plasma cutting and beam cutting and drilling.

In order to achieve an “exact” fit to the existing ground floor walls, these were measured up using sophisticated laser measurements (performed by Richard Logan surveyors).  The layout model developed from the laser measurements was imported into TEKLA and the structural steel layout superimposed to ensure a proper fit up.  An anchor bolt drilling template was developed on the same layout.

The TEKLA model was also used to fully integrate the building, structure, and services.  Where possible the structural elements were modified to incorporate add-ons such as:

  • Facia mountings
  • Service channels
  • Gutter recesses
  • GRP sandwich mountings
  • Channels for the deck and mezzanine frameless glass balustrades

Corrosion protection was achieved by employing a duplex coating of hot dip galvanising and a two-part epoxy paint.

The first component to arrive on site was the anchor bolt drilling jig.  This was assembled and put into place on the existing walls and concrete ring beam.  Key anchor bolt positions were marked and drilled, thus ensuring proper fit-up of the steel structure.

Construction of the steel structure and logistics had to be carefully planned and synthesized with mobile crane presence on site which had to be minimised (55t mobile crane with 30m reach). The structure was delivered in 3 loads from Gauteng.  The loads carried items prioritised to suit the build.

The build was subcontracted to WPM Construction and completed within 14 days of the first steel arriving on site.  In total only 3 days of mobile crane presence were required.  The long reach of the 55-ton crane allowed sub-assemblies to be lifted in position without damaging any of the protected trees on the site.

From this point onwards the conventional build proceeded up to end March 2016.