SIP’s (Structural Insulated Panel’s)

Feb 11, 2014 | CPD

What are SIP’s?

Structural Insulated Panels (SIPs) are a structural boards made from a sandwich of two layers of OSB timber boarding filled with one layer of insulation. The bonded sandwich gives the boards high tensile strength, allowing them to be used as structural elements. The benefits of this is that the structure is thinner than traditional methods – optimising your sites floor area, and being fabricated in factory conditions guarantees you a consistent standard.

What can I use SIP’s for?

SIPs can be used as the inner skin of a cavity wall, or can be used as a pre-insulated roofing structure. They are a very flexible product and can be used with any external cladding; brick, render, weatherboarding, metal cladding etc.  Likewise they can be roofed with slates, tiles or metal or even green roofing.

They are suitable for new builds, home extensions, garden studios, in-fill panels between other structures or even just the roof in re-roofing situations.

What are the benefit’s of using SIP’s?

The SIP’s are prefabricated in a factory to the exact sizes specified by your Architect, including window/door holes and angles for pitched roofs. This benefits the project in several ways:

  • Speed – It allows the structure to be put up on site far quicker than the traditional wet trades as well as the traditional timber frame construction.
  • Accurate costing – There are no unexpected site conditions to hamper construction (unless contractor builds floor slab the wrong size…) and the rapidity of construction reduces the risk of bad weather prolonging the build.
  • Low U-values – The level of insulation used achieves low u-values (as low as 0.14) on your walls and roof helping you to heat your building more efficiently.
  • Reduced cold-bridging – With timber frame structures there is a repeating cold bridge in the structural timber studs, due to the SIP panels being structural themselves they do not have this issue. Therefore there is minimal cold bridging in the walls.
  • Air-tightness – Due to the prefabricated consistency and accuracy the pieces fit together tighter, giving little to no air leaks. This is a very desirable quality if you are considering a Passivhaus.
  • Greater loft space – The panels being structural means that there is no need for roof trusses, giving a larger unobstructed and usable volume in your loft.


Where can I not use SIP’s?

SIP’s can be used in most situations although they are not suitable for:

  • Basement construction.
  • Wide spanning structure (unless used in conjunction with a steel or equivalent frame)


For more information visit the Structural Insulated Panel Association’s website


Written By: A Wiseman
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