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SIP Roof Solution

November 19, 2012

Plasti-Fab Solutions Home: SIP Roof
Written by: Dave Stevenson
Insulspan Division, PFB Corporation

In keeping with our Plasti-Fab Solutions Home blog series; after previously discussing below grade insulation, ICF foundation and above grade ICF and exterior rigid insulated sheathing wall systems; as well as SIP floor and wall applications, the next obvious topic for discussion would be that of ‘how best to insulate the roof of the house’? The answer really depends on the roof design, but in most cases a SIP roof can be the perfect solution.

First off, it is important to understand that SIP roof panels are not intended to be installed on top of standard trusses. They are intended to replace the trusses altogether in order to create design possibilities more commonly associated with a post and beam style of construction. This doesn’t mean that the panels can completely support themselves. In fact, the panels still need to be supported by beams or rafters of some sort, but the resulting open space can be left as a vaulted ceiling above a great room, a mezzanine level can be added, or even an entire upper floor. The maximum span between these beams or rafters will depend on the snow load, the thickness of panel, and the spline connection at the panel joints.

So flat roofs, gable roofs, shed roofs, winged roofs, gambrel roofs, and even roofs with dormers work very well with SIPs. But ‘why’ you ask is a SIP roof any better than a conventionally framed vaulted ceiling? So glad you asked.

Aside from the fact that you get all this extra volume and the aesthetic appeal of a cathedral ceiling in a timber framed building, roofs built with SIPs also combine the tedious labour of framing, sheathing, insulating and vapor barrier into an ultra-quick, one step installation process. Talk about a time savings! Consider this, a typical 3000sqft roof panel package can take an experienced crew as little as 2 days to install. Just try hand framing, sheathing, insulating and installing vapor barrier to a 3000 sqft vaulted ceiling.

And then there’s the sustainability and energy saving aspect of the roof panels:

SIP Roofs Save Resources
The major components of SIPs, Expanded Polystyrene (EPS) and Oriented Strand Board (OSB) take less energy and raw materials to produce than other structural building systems.
• EPS is 98% air
• EPS is recyclable; even the ‘off cut’ material from the manufacturing process can be returned to the EPS molder for use in the manufacture of other EPS products
• EPS provides long term thermal resistance; when used in SIP applications, it will save many times the energy embodied in the petroleum used to make EPS
• OSB is manufactured from fast growing, carefully managed forests
• OSB does not contain any urea-formaldehyde adhesives

Not only are the raw materials used to manufacture SIPs less taxing on the environment from manufacturing standpoint, but there are actually less raw materials required to build a SIP house. Consider this; a SIP building typically uses about 30% less dimensional lumber because studs can be placed every 48” compared to standard 16” or 24” o.c ‘stick frame’ construction.

SIPs also drastically reduce job site waste. Because the panels arrive pre-fabricated and ready to install, there are no off cuts, insulation left overs, plastic bags, or scrap pieces of vapour barrier to deal with.

So not only do SIPs save resources in production and minimize waste generation, the high R-value and airtight nature of the building envelope also reduces the amount of gas and electricity used in heating and cooling the house.

Finally, a Life Cycle Analysis (LCA) conducted by BASF comparing SIPs to conventional stick framing revealed that SIPs have a significantly lower impact on the environment. Not only do they save natural resources and energy, but they also help to decrease carbon emissions. BASF Sips Life Cycle brochure

Learn more about Insulspan SIP Roofs @

Next week we will cover the last solution for our home using PlastiSpan Insulation to insulate a cathedral ceiling. Stay tuned as we wrap up our series in the coming weeks.

One Comment leave one →
  1. April 9, 2013 10:46 pm

    I agree! I still am stunned this keeps happening again and again in modern day times. This news was well received as I am not running. We would love to have pondered for the future. Anyway I will keep track of this situation to this.

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