What are SIPS?
A structural insulated panel (SIP) is a form of sandwich panel used in the construction industry. A SIP is a sandwich structured composite, consisting of an insulating layer of rigid core sandwiched between two layers of structural board, used as a building material .
Some of the arguments for building with SIPS include:
Faster construction
Less waste
High R-value.
Integrated Structure
Should you use SIPS on your new home?
Being open to new technology and innovation, I looked into it using SIPS my own house. I even designed a version of the house using SIPS and then got it priced for construction to compare with a timber framed home of equal performance. Here is what the process taught me about SIPS.
Time Saved - is it worth it?
The time saving may not be worth the additional cost of the SIPS products over timber frames. In construction terms, erecting the building structure only accounts for a portion of the overall build program. A site based carpentry team can erect a two storey timber home structure and make it weather tight in around 4 weeks. Prefabricated Frames can be erected in under a week. A SIPS build house claims to achieve this in 1 to 2 weeks. At best, a saving of 1 to 3 weeks over a 6 month build isn’t significant enough to justify the extra cost and complexity of SIPS, especially if you have to wait for a production slot for your panels to be manufactured, checked, delivered to site and erected.
SIP Suppliers and Pricing
There is limited number of SIPS panel suppliers around which means that there is a lack of competition in pricing. WA for example has two active SIPS panel providers, both of which have their own product composition, module dimensions and installation methods. These suppliers are relatively small without the large economies of scale to make SIPS pricing cost effective overall.
SIPS Installation
There is a limited number of tradesman with experience in SIPS so it is hard to get a price for construction that isn't loaded with risk. It is not just about the SIPS install itself. Builders, Electricians, Plumbers, Engineers, Air Con Installers are just a few of the contributors to your home that will have to adjust to working with SIPS, and in our building industry unknown factors ring big alarm bells. Every trade that deals with this unknown will want to add time and cost to your project cover the risk.
SIPS material efficiency
SIPS works particularly well when the home is designed specifically to the standard panel sizes in order to minimise wastage. This takes a significant amount of additional time and cost in design phase.
SIPS - all or nothing
If you do design specifically for SIPS, but later find the cost of building with SIPS is too costly then you are stuck with drawings that should be modified due to different wall thicknesses and detailing needs.
Also, Being a composite structure SIPS structures are difficult to modify later (you cannot simply remove walls or peel back cladding to add extra wiring for example).
SIPS Durability
SIPS are untested over long periods of time. Some SIP builders use silicon sealant to connect the panels. Over time this will degrade and allow water ingress. A NSW based company using SIPS recently went bankrupt due to a high number of their homes forming mould after installation. Mould in any home is massive issue, but in a SIPS home it is unfix-able. Water may even get inside the skin of SIPS as the home is being erected, but the issues wont arise until much later after the builder has left the scene and the warranty period has expired.
SIPS and building health
When the water does inevitably get in, the moisture has no way to leave the composite structure. This results in mould and material degradation. Mould in buildings is a serious health issue and can significantly impact the well being of occupants. The timber framed walls in a Leanhaus are designed to allow the structure to breathe so they can dry out even in the unlikely event moisture does get in down the track.
SIPS and sustainability
The individual materials that make up SIPS (foam, OSB, FC Sheet) cant be recycled due to the foam being bonded to the outside skins. This make recycling the panels cost prohibitive.
A SIPS building should be designed to use the manufactured module size in order to minimise waste.
For all the above reasons Leanhaus has rejected SIP based construction in favour of timber frames. We can achieve similar levels of insulation with air tightness almost as fast and more cost effectively than SIPS. We also use prefabricated timber wall panels, which can save considerable time and cost on a typical project.
Leanhaus is established to provide the right balance of cost, quality and flexibility based on many years of experience, research and knowledge around design, sustainability and construction.
Feel free to get in touch if you have any questions.