What are SIPs?

What are SIPs?

What are SIPs?

Structural. Insulated. Panels.

SIPs are wall, roof (and sometimes floor) panels. Fabricated from a slab of foam sandwiched between two plywood sheets. Actually, it’s not ply it’s OSB (oriented strand board).

The sandwich-panels can be up to 24’x8’ and are made in the SIPs factory, in our case Premiere-SIPs in Puyallup. The doors and windows are cut-out in the factory, a stack of pre-fabricated house panels are loaded onto a trailer and arrives on-site where the SIPs are assembled… a bit like Legos.

Because TC Legend Builds affordable Net Zero energy houses, we use our crew to assemble the wall panels, man-handling them into place, but a crane can be used for walls. We do use the crane to set to thicker, heavier roof panels.

Our goal with SIPs panels is to create a continuous foam box, surrounding the inside of the home. When you remember that there’s 4” foam under the concrete slab, the 6” foam walls and 10” foam roof trap all the heat inside the house.

The ‘S” in ‘SIP’ stands for structural and the panel-system carries the load of the house, floors and roof, and does not need the sticks of vertical lumber you see in the walls of a conventionally framed house.

How are SIP panels joined? We’ll use the walls as an example:

The SIPs panels typically have the interior foam held-back to form a 1.5” gap at the panel edges. Two panels are joined by setting a ‘spline’ into the recessed gap on one panel, then sliding the second panel over the spline, nailing the connecting spline in place through all four edges. Splines can be made of 2×6 lumber (L-spline), foam mini-SIPs (called S-splines), or an insulated TJI spline (called an I-spline).

Because a 2×6 lumber splines touches both the warm inside of the house wall, and the cold exterior of the house wall, they are said to cold-bridge. A cold-bridge creates a poorly insulated pathway for the warm inside energy to travel to the cold exterior. There a many cold-bridges in conventional framing and that’s why we don’t do it. We aim to minimize L-splines as they have an insulating value of R7.8, compared to R29 for our Neopor graphite foam 6.5” Premiere SIPs wall panels.

Last week the TC Legend Homes crew finished off the SIPs roof structure on the Lake Stevens house.

On average we take about (2) days to assemble the 1st floor SIP wall panels. We build the 2nd floor-level TJI and sheeting floor system over the succeeding (2) days. The upper level walls take a day or so, and then it’s roof-day!

On roof-day the crane arrives early, and the roof panels are rigged, swung up, and screwed in-place by Ted and Norm. The crew have pre-assembled the boundary supports, so we don’t use more crane time and belch more diesel than necessary. The boundary support is a continuous 2×10 that seats into the 1.5” perimeter recess & connects together the outside edge of the roof panels.

SIPs are very fast to assemble and incur almost no waste material onsite because everything arrives pre-cut. Most excess off-cut foam is recycled back into the process during factory fabrication and the Premiere software nests the required panel shapes for maximum efficiency, making Premiere more streamlined, more profitable and more environmentally responsible.

Air sealing is very, very important for energy efficiency.

Imagine a fast, cold wind blowing over the building and all the warm air streaming out through the construction cracks. The Lake Stevens house is modeled to need a maximum of 12,500Btu/ hour to heat in midwinter, if we air-sealed the envelope to 0.6 air-changes per hour. (Note: (1) air-change-per hour assumes the entire volume of the house has the air replaced once within (1) hour).

If we air-sealed the Lake Stevens house to 5.0 air changes per hour, code minimum, we’d need 19,000Btu/h of heating for midwinter! So you can see that air sealing to reduce the air-changes per hour can give over 35% reduction in heating load.

SIPs are a pre-sealed sandwich, and compared to typical construction there are far fewer construction-joints in a SIPs building due to the large SIPs panel size.  The standard SIPs assembly process includes installing beads of specialist mastic to air-seal and adhere the panels to each-other.  SIPs have a measurable dollar advantage with that high level of pre-sealing and easy panel-to-panel air sealing. Meaning you can buy and run a smaller heat pump. And we haven’t yet examined the standard R29 insulation in the equivalent 2×6 wall!

…more in Part 2.

SIPs Structural Insulated Panels

2018 Year in Review

2018 Year in Review

Here at TC Legend Homes, we are excited to ring in the New Year! We kept busy in 2018, but we were not as active as we would have liked in keeping our “fans” updated on our recent projects. So, while we’re committing ourselves to doing better in the future, this post is an attempt at bringing everyone up to speed on some of the happenings of 2018 in a (relatively) short summary:

Homes:

  • One home completion (started in 2017) in Seattle.

  • Four complete home builds; two in Bellingham, one in Redmond, and one in North Bend.

  • Construction initiation on two ADUs; one in Sumas, and one in Bellingham.

  • All projects were Built Green 5-Star Certified, EPA Indoor airPLUS certified, and met DOE standards as Zero-Energy Ready Homes.

Events:

  • Ted presented at the Built Green Conference 2018 in Seattle. He shared the podium with homeowners Andri Kofmehl and Veena Prasad. Their topic, Bridging Innovation and Affordability: How to Build the Greenest House Possible Without Compromising on Aesthetics or Breaking the Bank, featured our 2017 Emerald Star home. More details on this can be found at this link to our portfolio.

  • Craig and Thad did a little San Diego couch surfing to attend a Builder’s Round Table, composed entirely of 2018 Department of Energy Housing Innovation Award Winners, where we learned a little about the future of high-performance building.

  • We participated in the Whatcom County Showcase of Homes, featuring the second home shown above – a great example of an affordable net-positive home in Bellingham. You can also read more about it in our portfolio.

  • Ted and Thad spoke at the Northwest EcoBuilding Guild’s annual Green Building Slam about how building net-positive can actually make it easier to afford more home while preserving quality of life.

  • We “expanded” our business operations into a SIPs Tiny Office (above).

  • Ted wrapped up his speaking engagements in December, at the Sustainable Connections Green Building Slam, with a talk about why we need to embrace sustainable building – because Our Kids are Going to Need a Place to Live.

Accolades:

Next Century Seattle Homes

Next Century Seattle Homes

Our newest project is almost complete! These homes were designed to be sustainable without compromising the luxury one expects in high-end building. Located in central Columbia City, the homes are just two blocks from the the core shopping and restaurant area and just three blocks from the light rail station, earning a Walk Score in the 90s. The homes’ many windows offer views of Mt. Rainier and the Cascades. 

Featured Home

  • 2,250 square feet
  • 5 bedrooms
  • 3.5 bathrooms
  • Recreational spaces
  • Living room
  • Dining room
  • Kitchen
  • Mudroom
  • Laundry
  • Driveway/parking

Amenities

  • All heated floors
  • Triple Pane Windows
  • Stainless Steel Appliances
  • Induction Range
  • In-House Air Filtration System
  • Solar Panels
  • Electric Car Charging
  • 9 Foot Ceilings
  • Exposed Beams
  • Fenced Yard
  • Outside Patio

Positive Energy

These positive-energy homes use non-carbon-based sources of energy to produce 100% of energy needs for appliances, heating, and lighting. Additionally, the homes generate enough energy to power an electric car. This means no utility bills or additional charges to operate your electric car. And, most importantly, a positive-energy home does not produce carbon emissions, which are responsible for global warming. Living in a positive-energy home is one way of “doing your part” to ensure continued habitability of our planet.

Learn More

Visit the links below to follow the building process and learn more about how these custom-designed homes incorporate the latest technology to ensure the highest levels of energy efficiency and quality. 

https://nextcenturyseattlehomes.com
https://www.facebook.com/nextcenturyseattlehomes/