Structural Insulated Panels (SIPs) come prefabricated and ready to be assembled in site.
It’s easy - and very quick - to build walls, roofs and floors with them, but there are cons that should be considered.
Is SIP construction cost-effective and worthwhile?
SIP construction is growing at high rates (30% in the last years, according to SIPA), but the market share is still low: about 1% of the European and North-American market.To begin with, here is a list of the advantages of SIP construction:
- Air-tightness: SIPs can provide high levels of air-tightness and insulation; all SIP-constructed homes are automatically qualified as a low-energy home by the Energy Star home certification program.
- Quality and airtighness: SIPs can provide high levels of comfort, energy-efficiency, and structural stability. The amount of energy savings depends on the thickness of the panels (see table above)
- Seismic and hurricane resistance: SIPs provide good structural strength and stability, as demonstrated in hurricane and earthquake affected regions (in Japan and South of the United States).
- Construction times: SIPs help to reduce on-site construction times and requirements; you will need days to erect a house, not weeks or months.
Environmental considerations: SIPs are usually considered an eco-friendly choice; not only because they can provide huge energy savings but also because of their recycled content and because there are green options for their cores and boards.
- Costs: SIP construction requires minimal equipment and workforce. Construction costs are not very different from those of wood-frame construction, though that depends also on design considerations and the type of panels. On the long run, considering the energy savings, SIP construction can be an advantageous option.
the Importance of the design
Pay special attention to design considerations; the architect should work closely with the SIP manufacturer. A collaborative approach is crucial.
Boxy homes will be easier to construct and cheaper.
Also take into account the standard dimensions of the panels (4 feet wide, and heights of 8 to 24 feet) when planning the position of the windows and doors, and the size of your house. That may also be important to reduce costs and waste.
SIPs construction: the disadvantages
SIPs offer a few advantages over traditional building construction methods. But you should be aware to possible disadvantages and constraints. We outline them below:
- Moisture resistance: SIPs can be damaged by moisture, and should be carefully protected. Prefer panels with waterproof surfaces, or fiber-cement panels. They are pretty much foolproof.
- Pest-resistance: the core of the SIPs panels is not exactly the ideal place for pests to multiply, but the panels should be properly protected from pests. Panels should be treated with inexpensive and harmless (to people and to animals) acid boric, or other insecticide, especially in climates with cold winters and warm summers.
- Prior prerequisites: manufacturers use computer-controlled equipment to size and to cut the panels according to the CAD drawings supplied by their clients; that’s important for quality control and to minimize waste. But that requires collaboration, and an accuracy. The panels have to be cut to specific sizes and pre-drilled for electric wiring and plumbing, and have to consider the doors, the windows and other architectural features.
- Know-how: many builders – and their workforce - are not familiar with SIP construction; it requires some know-how...
- Ventilation system: SIPs provide high-levels of air-tightness, but that requires a proper mechanical ventilation system.
- Modifications to the initial project: Though possible, modifications to the initial project can be pricey. An example: You can easily increase the size of a window, but the reverse it's difficult...