SIP walls assembly

Day 1

I had been concerned about the offloading of the panels for some time, trying to think of the best way to handle it.
Insulspan recommends a forklift with 8′ fork extensions. Having that you can easily lift of the bundles, but no one around here offers that so we needed to think of an alternative solution. I had three options in my mind: offload by hand, use a truck with smaller forks and slide the panels off one by one into it or bring in another truck with a crane on it.

After discussing it with the contractor we decided it would be best to bring in another truck. This way we could lift the bundles off the delivery truck and place them straight on the floor deck.
We called a local concrete form supplier who also rents out his truck and crane and scheduled him to arrive at the same time as the delivery truck.

The panels arrived early in the morning at 8 o’clock. The panels came shipped on a flatbed truck and trailer from Delta, outside Vancouver on the mainland. Our offloading crane arrived shortly after and we could get started.

Delivery truck arriving

We backed in the crane truck first and backed up the delivery truck next to it. Offloading the panels this way was a breeze and little less than two hours later both trucks were gone and the panels were sitting in the house ready for breakdown and assembly.

Unloading the SIPs using a second truck, with a crane


The process started by identifying a corner to start with and which panels goes where. The bundles come from the factory in a random order, so it takes a bit of organizing and sorting before you can really get started.

The assembly process itself starts with confirmation of the foundations square- and plumb-ness. Matt Meier, our concrete contractor did a fantastic job on the concrete and everything fit perfectly.

There are various ways you can connect the foundation, floor system and panels together. We chose to hang the joists off the foundation walls, extend the floor sheathing over the mudsills and then build the panels on top of the sheathing.

You start by laying out your bottom plates. These get set back from the outer face of the wall by about 1/2″. The SIPs panels have the foam recessed at the bottom and “slip on” top of the bottom plate before getting nailed in.

Every wood-to-wood connection gets a continuous bead of polyurethane glue. This is a crucial step as it acts both as a glue and sealant. The glue WILL get all over you.

At this time you also need to check the wood splines between the panels to make sure the wire-chases have been drilled. In our case all the chases were properly drilled in the splines. The only drilling we needed to do was in the corners to enable pulling of wires.

With the bottom plate installed and the connections glued the panel can get put in place. It is as simple as slotting the panel in, making sure it is plumb and square before you nail it in.
We lightly tacked the panels in at the start and not until we had a full wall did we fully nail the panels according to the prescribed nailing pattern.

The final step is to screw in large, specially made SIP screws. These are 10″ long case-hardened screws with a 800-lbs pullout resistance. Screwing these in at 12″ intervals almost nothing can rip the walls apart. Trying to screw them in with a cordless impact-driver can be a losing battle as it powered out all the 18V ones we had available. It is best to use a powerful corded drill to screw them in.

Repeat with the next panel. Glue, place, check, nail.

Around windows and doors the panels are split into top and bottom pieces. In some places these pieces can get very heavy, such as the piece above our double doors in the living room. It took some planning, and a ton of effort of 4 people to get the piece up and nailed in. We contemplated getting the crane out again for this piece but the contractor managed to get it in using various braces and lots of muscle.
There were two pieces like this, and they were the most challenging pieces to place in the whole house.

End of first day

Day 2

The next day called for rain and there was lots of it. One thing that Insulspan could not stress enough was “Don’t let the panels get wet”. We tried our best to keep the panels covered as we worked but inevitably some of them did get wet. If the edges of the panels get wet, the OSB skins can swell up and the tight manufacturing tolerances can make the process of slotting the pieces together a lot more challenging.

When we got to a part that had problems slipping together easily they shaved of a tiny slice of the wood splines and lightly chamfered the corners.
After those steps the panels went together much easier. In some cases we used ratchet straps and a sledgehammer to fit everything together.

On this day we also put in the prefabricated stairs. The only challenging part was lowering the stair landing from up top. To do this we used the lifting plates that Insulspan had provided. Screwed them on to the landing and the four people dropped the landing down from up top using ropes. It was a tight fit, but just right.

Assembling prefabricated stairs


Day 3

On the third day the crew continued placing panel after panel, moving moving very quickly. Before putting the last wall panel in place we moved the rest of the prefabricated walls inside.

Caulking all the joints

Last panel being placed

The contractor we chose had never worked with SIPs panels previously but seemed quite interested in learning. Having built R-2000 houses previously he also understood what we were trying to accomplish with our choice of prefabrication and superinsulation.

So that wraps up the assembly of the walls. The next post will involve the roof trusses and roof panels.


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