PREFAB SPROUT INT uses only the best quality materials that are eco-friendly.

Alternative Build Technologies and SIP panels


Hot dip galvanized steel sheeting 0.8 and 0.58 mm thick, is slit and formed into the stud framework that provides extra structural strength to the SIP panel.


SIP panels are manufactured from three major components. Magnesium Oxide Boards (MgO), a light weight steel frame and Polyurethane foam (PU).

Polyurethane foam is injected into the middle of the SIP panel and binds the other components together. It also provides thermal properties to the SIP panels.

The insulation in the polyurethane insulated panels creates a conducive environment for working, learning and living and is especially suited to our temperate climate on the African continent, and similar environments.

Structural Integrated Panel (SIP) Systems

  • SIP systems are 20% to 30% cheaper than traditional brick and mortar over the total project.
  • Higher thermal properties are achieved using SIP panels, creating a more energy efficient dwelling.
  • Project lead times are reduced up to 50% when building with SIP panels.
  • SIP panels are rodent and insect resistant as there is no food source in the make-up of the panel.
  • SIP panel systems require less labour than traditional brick and mortar and the buildings can be built with semi-skilled labour.
  • Limited impact on the environment is made as no scarce resource are used on site to build the building.

SIP panels are manufactured from three major components. Magnesium Oxide Boards (MgO), a light weight steel frame and Polyurethane foam (PU).

Magnesium Oxide, or magnesia, is a white solid mineral that occurs naturally as periclase and is a source of Magnesium. It has an empirical formula of MgO and it is formed by an ionic bond between one Magnesium and one oxygen atom.

The majority of Magnesium Oxide produced today is obtained from the processing of naturally occurring minerals such as magnesite (Magnesium carbonate), Magnesium chloride rich brine, and seawater. In addition to seawater and lake brine sources include also, Carnalite, Dolomite, and Serpentine Magnesite.

A classical magnesium board is a sandwich board consisting of the core from powdered perlite, surrounded on both sides with a mesh from glass fiber and magnesium layer MgO or magnesium-cement layer, which is often reinforced (in a dispersed manner) with cellulose fiber with the addition of other derivatives of magnesium compounds, such as magnesium chloride – MgCl2.

MgO Board Composition

  • Magnesium oxide [MgO] (40%)
  • Magnesium chloride [MgCl2] (35%)
  • Wood chips (15%)
  • Perlite [SiO2] (5%) (volcanic glass)
  • Small glass cloth (1%)
  • Linking composite materials (4%)

Magnesium Oxide Board is made by the above formula of chemicals. The stable magnesium celluloid is reinforced by glass fiber netting. It has the advantageous features of being light weight, strong, very low contraction properties, flexible yet impact resistant. It has excellent drainage properties, is fire resistant, and is very easy to work with. It can become waterproof by sealing it; corrosion proof and plasticity are better than wood, paper surface plaster board or gypsum board and cement fiber board. Most importantly Mgo board is cured without the use of any heating and thus using very little energy unlike gypsum board and cement fiber board. This makes it greener and although it is a product of the past is fast becoming the product of the future for these reasons.

Magnesium board Main characteristics

  • Density (g/cm3): 0.85-1.05
  • Bending strength (M/mm): 18 -27Mpa
  • Breaking load: 113-498
  • Thermal resistance:1.14m2k/w
  • Sound Insulations:>44dB
  • Shrinking rate when heated:1.0%
  • Facial surface hardness 5.9-8.3 Mpa
  • Surface moisture absorption no more than 0.34%
  • Water absorption capacity 15%
  • Vapor permeability, mg/m*h*Pa 0.11-0.14
  • Rate of length change (wetting %): Below 0.26%

Non-flammability: Fireproof 1st grade


A variety of raw materials are used to produce polyurethanes. These include monomers, prepolymers, stabilizers which protect the integrity of the polymer, and colorants.

One of the key reactive materials required to produce polyurethanes is diisocyanates. These compounds are characterized by a (NCO) group, which are highly reactive alcohols. The most widely used isocyanates employed in polyurethane production are toluene diisocyanate (TDI) and polymeric isocyanate (PMDI). TDI is produced by chemically adding nitrogen groups on toluene, reacting these with hydrogen to produce a diamine, and separating the undesired isomers. PMDI is derived by a phosgenation reaction of aniline-formaldehyde polyamines. In addition to these isocyanates, higher-end materials are also available. These include materials like 1,5-naphthalene diisocyanate and bitolylene diisocyanate. These more expensive materials can provide higher melting, harder segments in polyurethane elastomers.

The other reacting species required to produce polyurethanes are compounds that contain multiple alcohol groups (OH), called polyols. Materials often used for this purpose are polyether polyols, which are polymers formed from cyclic ethers. They are typically produced through an alkylene oxide polymerization process. They are high molecular weight polymers that have a wide range of viscosity. Various polyether polyols that are used include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These materials are generally utilized when the desired polyurethane is going to be used to make flexible foams or thermoset elastomers.

Polyester polyols may also be used as a reacting species in the production of polyurethanes. They can be obtained as a byproduct of terephthalic acid production. They are typically based on saturated aromatic carboxylic acids and diols. Branched polyester polyols are used for polyurethane foams and coatings. Polyester polyols were the most used reacting species for the production of polyurethanes. However, polyether polyols became significantly less expensive and have supplanted polyester polyols.

Some polyurethane materials can be vulnerable to damage from heat, light, atmospheric contaminants, and chlorine. For this reason, stabilizers are added to protect the polymer.


  • Wall height is 2400mm or 2700mm high
  • Width is 1200mm or 600mm infill
  • Thickness is 110mm external or 90mm internal panel
  • The current capability of manufacturing up to 200 x 40m2 houses per month on a 3 shift basis
  • Suitable for all types of housing, schools, and clinics. Modular building systems can build up to two stories
  • Electrical conduits, plug boxes and switch boxes are cast into the panel
  • Plumbing conduits are cast into the panel
  • Steel or aluminum window frames and door frames are foamed into the panels
  • Timber window frames are fitted on site if required
  • The modular building solution structure is built either on a lightweight concrete raft foundation or an elevated steel flooring system
  • A bottom track is bolted to the concrete or steel foundation
  • The panels fit over a bottom track and are screwed in place


The Sandwich panel is a composite panel consisting of an inner and outer skin and an inner core of injected polyurethane foam. The inner and outer skin are 0.5mm steel sheets that can be ribbed or not.

The panels are manufactured with a tongue and groove system that provides thermal insulation and strength when the panels are joined together during the building process.

The panels can be produced in thickness from 30mm to 100mm and varying lengths depending on the customer’s requirements.

SIP systems are 20% to 30% cheaper than traditional brick and mortar over the total project.