We often get asked questions from our clients about SIP’s as a potential method for building. To help you get a better idea about the benefits of this system, we have answered a few of the most frequently asked questions.
What are SIPs?
SIPs is the abbreviation for Structural Insulated Panels, a high performing composite building system which can be used on residential and light commercial construction as an alternative to traditional building methods, such as brick and block or timber frame. The panels consist of an insulated foam core, positioned between two timber boards, joined together with timber splines. Creating a pre-fabricated construction system for walls, roofs, and floors.
We are currently using them onsite at our Courtyard House project, in the New Forest National Park, we are utilising this construction method for several reasons. The first was our desire to build a lightweight, low energy, sustainable home, which we could deliver with this building method. The second was due to the logistics around the site, because is it small and constrained we were able to greatly reduce the need for storage onsite, as building with SIPs means it is prefabricated and 50% of the construction happens off-site.
What are the benefits to building with them?
A key benefit when building with this system is the speed of construction onsite, as they are factory made to exact measurements, the construction time needed onsite is vastly reduced, on average down by 55% from traditional construction methods. This time reduction can have a really significant impact in lowering the budget for the construction aspect of a project.
Another benefit of using this system is the high-performance credentials, with inherent airtightness and a ridged insulation core to help reduce air leakage within a building. Additionally, due to the boards being factory produced they can be used with a larger vertical stud wall spacing (traditionally the spacing is at 600mm centres, but can be at 1200mm centres with SIPs) reducing the cold-bridging in the construction.
What are the disadvantages of using them?
Due to the system being factory built, there is a lot of pre-construction work and co-ordination needed between SIP manufacturer and Architect. As once onsite it is difficult to make last minute changes as you might using traditional methods, this needs to be taken into consideration from the start of the detailed design.
When designing a building using this method of construction, the ventilation needs to be carefully planned, as due to the airtight qualities of using SIPs method without adequate ventilated there is a risk of condensation build up, and the internal air becoming stale.
Additionally, as the construction process is specialist, there might be less choice of suitable and experienced contractors available when looking to complete the work for you. Look out for SIP companies who supply and install to get a full package.
Can I use for an extension, or whole house?
It is a versatile system which is suitable for all residential and small commercial projects, both to create whole new builds, or to be used as an extension on a traditionally built property.
Are SIPs cheaper to build with?
The cost depends greatly on the project, but usually it is not a cheaper way to build. It is good to understand that although the initial outlay in the cost of materials when using SIPs is more expensive, there are significant savings to be made in terms of time needed on site construction, compared to traditional building methods. For our Courtyard House Project the cost was very comparable to traditional timber frame, however the savings came in the time and labour, and therefore worked out more cost effective overall.
Are there any projects that SIPs are not suitable?
SIPs are a timber-based building system and so are not good to use in moist conditions, so the system is not suitable for projects like basements or sites within flood zones. In these instances, it would be better to use a traditional system at least on the lower floors, you could always introduce SIPs panels on upper levels of a building.
You will also need good access to your site, to ensure the panels can be delivered and the right plant machinery can get to the site in order to manoeuvre the panels around. This need not always be a barrier though, as for our tricky site in the New Forest we had a good understanding with the SIP supplier and deliveries were made in smaller loads and lifted by hand or used small winches. As it is a lightweight construction method, it is not always necessary to need cranes for construction.
Like all building methods it is about understanding what is the best possible method for the site, design, budget, performance goals, and the day to day running on site.
Get in touch if you would like to discuss how we can help you with a SIPs built home.






