A High-performance advantage.

I Joist
Ecostructural I-Beams

I-Joist Basics

I-joists are strong, lightweight, "I" shaped engineered wood structural members that meet demanding performance standards. I-joists are comprised of top and bottom flanges, which resist bending, united with webs, which provide outstanding shear resistance. The flange material is typically laminated veneer lumber (LVL) or solid sawn lumber, and the web is made with plywood or OSB. The robust combination of structural characteristics results in a versatile, economical framing member that is easy to install in residential and light commercial projects

Case Study 1

RSB I Joist

Patio enclosure

I-Beams for permanent structures and best suited for flat/lean-to roof structure, patio enclosure, heavy duty floor structure, flat roof deck, passive solar roof structure, etc. Tapered I-Joists with parallel fascia girder on a private house near Randburg South Africa. In spite of relatively small rafter spans, the girder members were deep and had long spans which also formed a fascia
Max Rafter Span4230mm
Max Girder Span5800mm
Rafter ProfileTapered (1.5°)
Rafter c/c813mm
Deck18mm shutterply
Total Area32m²
Applied Load.7398 kN/m

Case Study 2

heavy Duty Floor Structure

 Heavy Duty Floor Structure

This was part of a refurbishment project for Planet Fitness at their Durbanville facility in the Cape Province. Both alternative methods of construction proved to be considerably more expensive. Timber I-Joists were specified and the cost saving was 43%. The structure was installed by the main contractor who used 2 carpenters and 2 labourers who completed the project in 3 weeks. There were 21000 chipboard screws and 355 hexagon bolts. The structure spanned over change rooms which meant that continuous moisture had to be taken into account. The I-Joists were pressure treated TBTN-p followed by 3 coats Rystix Timbercare.
Max Rafter Span7500mm
Max Girder Span7500mm
Diaphragm Deck21mm Shutterply
Applied Load6.5kN/m²

Case Study 3

Tyger Valley College

Tyger Valley College Pretoria.

This project was part of an extension to existing facilities. The roof structure had initially been specified as steel I sections which were heavy and considerably more expensive than timber I-Joists. The I-Joists were delivered in single lengths and a crew of only 1 carpenter and 3 labourers installed roughly 3000m² of roof. The exposed rafter cantilevers were treated with 3 coats Rystix Timbercare exterior deep penetrating sealer.
Max Rafter Span9000mm
Rafter c/c:1250mm
Roof Pitch15°
Total Rafter Length11000mm
Roof Cover:Steel Sheets
Applied Load:.7375 kN/m

Case Study 4

Flat Roof Deck

Flat Roof Deck

Private Dwelling Plettenburg Bay. The original specification for this roof was cast in- situ concrete. The Project Manager discovered tapered I-Joists and the specification changed. This was a very challenging roof profile, but this tapered deck saved the client 33% in cost and reduced the build time by 3 weeks. There were 36 different lengths of tapered I-Joists Supported on a steel skeletal frame.
Max Rafter Span5200mm
I-Joist c/c:813mm
Applied Load.7398kN/m

Case Study 5

Passive Solar Roof Structure

Passive Solar Roof Structure

Private House Ou Baai near George South Africa. This building was designed by an architect who is passionate about alternative building technology. The near zero carbon footprint of timber I-Joists complimented the ethics and was more economical than laminated beams. The roof consisted of 50x76 purlins on top of the rafters and 21mm shutterply on top of the purlins. The roof covering was Tegola felt shingles, an ideal specification for coastal applications. All exposed timber was treated with 3 coats Rystix Timbercare.
Max Rafter Span8000mm
I-Joist c/c:1200mm
Roof Pitch15°
Purlin c/c610mm
Applied Roof Load.9720 kN/m

Case Study 6

Level studio roof

Roof Level Studio

Private Dwelling Northcliff Johannesburg. The brief was to create a studio on top of the existing building which did not have adequate foundations for conventional construction methods so had to be lightweight. There were to be no internal walls and the client wanted a vaulted ceiling. This structure consists of laminated portal Frames, I-Joist rafters and I-Joist floor members. The existing ceilings were left in-situ and screwed to the bottom flanges of the I-Joists.
Roof Span8000mm
Portal c/c3300mm
Max Floor Span4800mm
Deck Cantilever1500mm
Applied Load Roof.9804 kN/m
Applied Load Floor.9467 kN/m

I-Joist BasicTerminology

The principle behind I-Joist technology is about putting strength where it is needed at the lowest possible cost. Hence the top and bottom flanges do most of the work, whilst the web keeps the flanges apart and takes care of shear forces.

The range of I-Joists we offer has been developed specifically for use on the African continent. Low level on site skills are required whilst at the same time the product is supported by engineering services on an internationally accepted level.
The maximum depth of the web is determined by a formulation that we have developed and which prevents the webs from buckling under heavy loading conditions. 


Ibeam Teminology
Ibeam Teminology

I-Joist is a cost effective, lightweight beam used in residential and commercial construction.

I-Joist is light, easy to install and available in a wide range of sizes, it also gives you more options for designing economical joist layouts.