• SIPs - Jul contracts

Advantages of SIPs

Building with Structural Insulated Panels (SIPs) offers many advantages throughout the whole design and build process, as well as the ultimate benefit of lifetime energy savings for a homeowner.

Take a look at some of the excellent benefits building with SIPs can offer, also click here to view our “Benefits of building in SIPs” pdf:

Design Flexibility

SIPs create new possibilities of design without the constraints of conventional building materials.

Additional Floor Area

SIPs create additional warm living space in the roof by eliminating conventional trusses. This can provide an additional 25% of floor space at no additional cost and makes use of all of the potential space in the building. A 3-bed house can become a 5-bed house for little extra cost.

Thermal Performance

SIPs can offer a thinner wall thickness than a conventional wall, but still offer improved insulation values, gaining greater internal space for the same size overall footprint.  Unbeatable insulation value means energy costs can be reduced by up to 60% over conventional construction.

Structural Advantages

Structural superiority has been proven by independent testing. Point loads can be dispersed through the structure.

Construction Benefits

SIPs are a far quicker solution for the construction of your house. Pre-cut and fabricated panels reduce installation time by up to 60%.  The building can be erected and weather tight in a matter of days, allowing internal fit outs and first fix works to start much sooner in the build timetable.


Once completed, a SIPs structure forms a shell up to seven times stronger than a conventional timber frame structure and is a popular building method in areas subject to earthquakes, tornadoes and hurricanes. This provides a building with a very robust and solid feel, which can be indistinguishable from a traditionally constructed building once complete.

Air Tightness and Ventilation

Poor air-tightness is a major cause of heat loss in traditional timber frame homes. The solid insulation core of a SIPs house helps eliminate this.

A SIPs home provides a controllable indoor environment due to the superior air tightness of the system. This is enhanced with the use of a Mechanical Ventilation with Heat Recovery (MVHR) system or similar.

Excellent Thermal Performance

Structural Insulated Panels provide superior thermal performance, which will last the life span of the building. The thermal conductivity of the polyurethane core is typically 0.14 W/m.ºK. Using SIPs panels can provide extremely low U-values for walls and roofs.

The insulation is integral to a SIPs Building System and therefore eliminates the need for, and cost of, cavity insulation.

Fire Performance

The SIPs panels meet all the required Building Regulations regarding fire resistance when lined with plasterboard. These requirements are similar to those for timber frame construction. A single layer will provide 30 minutes rating and a double layer 60 minutes rating.

Integral Insulation

The solid core of rigid PUR foam insulation in the panels cannot slump over time and the minimal thermal bridging ensures that the building is heated evenly, free from cold spots and condensation. The building will benefit from reduced heating costs for its entire lifetime. This is a very important consideration at a time of spiraling energy costs.

Rigid Surface for Fixings

The OSB skin of a SIPs structure provides a continuous surface for easy fixing of services, lights, radiators and kitchen units without having to build in additional support.


Structural insulated panels are relatively lightweight (approximately 20Kg/m2 for a 150mm panel) and can allow a reduced foundation specification.

Structural Performance

  • SIPs form a light and strong structure
  • Excellent for in-plane loads
  • SIPs buildings behave as thin shell structures, dispersing point loads to the entire surface area

Uniformly Distributed Load

Tests have shown that the panels have a very high ultimate bending strength. Deflection, calculated as described in the Design Guide, is the governing criteria in design. This increases user confidence, knowing that safe working loads are well in excess of standard deflection limits.

Axial Load

Axial loading tests on panels 100m thick, 2.4m in height and 2.4m in width were seen to fail at a load of 440kN/m. Using a factor of safety of 2.0 it is seen that panels will comfortably support a vertical load of 90 kN/m. These loads are well in excess of the average foundation loading from a typical two-storey house of traditional construction.

Resistant to Rodents, Mould and Microbes

The PUR (Polyurethane) core and the OSB facings used in the manufacture of Structural Insulated Panels do not provide any food value to vermin and are resistant to attack by mould and microbes.

Choice of Finish

A SIPs structure will form the hidden shell of the building. The external walls can then be finished in many ways. These can include traditional cavity and facing brickwork, timber cladding, brick slips and render systems. Internal walls are normally finished with fire resistant plasterboard. Roofs are finished as normal with battens and slates, although the inherent strength of a SIPs roof does not require the same weight of finish as a conventional vented roof void. This can allow the use of a lightweight roof finish if desired.

The Code for Sustainable Homes

Structural Insulated Panels contribute to The Code for Sustainable Homes through excellent thermal performance, air tightness and limited cold bridging.

British Board of Agrément (BBA)

The Structural Insulated Panels that we use at JML Contracts is a certified product of the British Board of Agrément (BBA). BBA Certificate

Reduced Cost of Foundations

A SIPs structure is a lightweight shell and therefore does not require a heavy foundation design.

Increased m2 Floor Area

A SIPs roof structure does not require roof trusses and will provide an open habitable warm room in the roof, allowing a three bedroom house to be turned into a five bedroom house on the same size plot.

Reduced Cost of Labour

A SIPs structure simplifies the process of construction and can reduce construction time by up to 60%. Once the foundations have been completed, our team can arrive on site with a pre-engineered structure and within 2 to 4 weeks will have erected a weather-tight structural shell ready for windows, doors, services and internal and external finishes. The nature of SIPs provides a square, smooth structure which helps follow-on trades and so reduces the eventual cost of snagging.

Reduced Cost of Waste Disposal

A SIPs structure is pre-engineered off-site to avoid both the additional labour and the ever increasing cost of the safe disposal of waste materials.

Reduced Site Costs

A faster build programme will reduce the overall cost of project management, and in turn will also reduce the cost of hiring scaffolding, plant, safety and security equipment and temporary accommodation.

Reduced Heating Costs

The unbeatable insulating qualities of SIPs allow a much smaller heating system, combined with a mechanical ventilation system, to be installed. This will permanently reduce heating bills by up to 60% over the lifetime of the building when compared with traditional methods of construction.

Environmentally Friendly Materials

The outer skins of SIPs panels are manufactured from Orientated Strand Board (OSB). This is made from young fast growing trees which are deliberately grown in plantations accredited by the Forest Stewardship Council (FSC). Young trees produce oxygen and remove more carbon dioxide from our atmosphere than mature trees and are renewable, recyclable, bio-degradable and non-toxic. The core insulation is polyurethane foam (PUR) which is CFC and HCFC free and has an ozone depletion potential of zero.

Reduced Timber Usage

To make a product with the same strength, timber uses 20% of the energy needed for concrete. Timber is naturally low in thermal conductivity and an excellent insulator. It is 15 times better as an insulator than concrete, 400 times better than steel and 1770 times better than aluminium. A 25mm timber board has better thermal resistance than a 114mm brick wall. When compared with traditional timber frame buildings, SIPs construction uses approximately 50% less wood, which all adds to the positive environmental impact of this form of construction.

High Insulation Value

Structural Insulated Panels provide an extremely high thermal performance and U-values can be as low as 0.14W/m²K.  There is minimal thermal bridging compared to conventional construction and the insulation will not sag or slump over time.  The construction is inherently airtight, warm in the winter and cool in the summer. This drastically reduces energy consumption, which leads to a corresponding reduction of up to 60% in carbon dioxide emissions from the burning of fossil fuels for the lifetime of the building.

Minimal Wastage

Building with SIPs produces less waste than other forms of construction.  The panels are engineered in a controlled environment, reducing the amount of waste produced on the building site and allowing unused materials to be recycled.