Thread: Steel Structural Insulated Panels (SIPs) - anyone worked with them?

Hi,
Youngest son is building with what he calls SIPs. But I think they are Structural Insulated Panels and skinned with a randomly spaced pressed plywood.
He was planning on using wood-fired hydronic floor heating, but dropped the idea after visiting his friend's SIPs house that didn't need additional heat in winter.
They are apparently very efficient thermal insulation.
Cheers .

Mate of mine made his trailer to carry his D type replica in.
They are heavy but that will not matter with a house. My main long term problem would be rust.
What about polystyrene bricks filled with concrete as has just been built near my house. That would be a good insulator and sound deadening.
Regards PhilipA

Originally Posted by austastar

Hi,
Youngest son is building with what he calls SIPs. But I think they are Structural Insulated Panels and skinned with a randomly spaced pressed plywood.
He was planning on using wood-fired hydronic floor heating, but dropped the idea after visiting his friend's SIPs house that didn't need additional heat in winter.
They are apparently very efficient thermal insulation.
Cheers .

Yep, SIPs are catching on in this part of the world. Quick builds and energy efficient. There are two key types of SIPs. The one you have seen are comprised of Oriented Strand Board (OSB ) sandwiching expanded polystyrene (EPS). Very strong, and over here in NZ OSB SIPs are on a par or slightly higher cost-wise to the normal stick-build costs. I looked at these but you end up cladding the exterior as the OSB was not suited to long-term weather exposure.

The ones I am looking at are made with galvanised steel sheeting 0.59mm thick in colour-steel colours. Aluminium joinery for fixing each panel to the others. Weight is slightly lower than OSB and there is no need to place exterior cladding on it once built although I have seen people do so. Weight of 100mm Steel SIPS is 12.3 kg/m2 and for 150mm is 13.1 kg/m2. R-values are 100mm thick R2.62 and for 150mm are 3.62. Both these numbers are higher than our minimum levels in the NZ Build Code.

Originally Posted by PhilipA

Mate of mine made his trailer to carry his D type replica in.
They are heavy but that will not matter with a house. My main long term problem would be rust.
What about polystyrene bricks filled with concrete as has just been built near my house. That would be a good insulator and sound deadening.
Regards PhilipA

G'day Philip,

Concrete and polystyrene sounds interesting. One option I am looking at is once a floor is in, setting up a couple of layers of concrete pavers inside and then placing some form of thin sheeting over them for thermal mass for gathering winter solar heat. I haven't quite thought things through yet how to finish the floor to an acceptable level while also still having the pavers heat up in the winter sun. I could just lay a raft of concrete on the final floor and polish this up but I would eventually like the option of trucking the whole cabin off-site once I am done with it. A trombe wall with thermal mass at the base could also be an option for solar heating. No concrete inside then.

Yeah rust worries me too a bit. Moisture control is a key to it I think. Painting cut edges is something I would consider necessary. Use of good sealant in the joints but also make sure moisture can leak out if it does get in there. I am sure there are tricks to it hence my question and posting. Breaking any thermal bridging looks to be a key part of design to avoid condensation. I have found a few diagrams online that are proving very useful.

The key reason I am looking at the steel SIPs is that the build could be temporary (about a few years ) and if I make them on a steel framework of bearers and joists on a conventional wooden piles arrangement I can lift them onto a truck with a hiab and haul them out of the place once I am done with them.

I'd be concerned about galvanic corrosion, Phil. Aluminum, zinc and steel.

Don't these panels come in aluminium ?

Originally Posted by V8Ian

I'd be concerned about galvanic corrosion, Phil. Aluminum, zinc and steel.

Good point Ian. I think I need to look into this further. I see massive big cool stores made out of this stuff and have stood over 30 odd years now so I wonder how they deal with it or whether it is an issue or whether it is an issue that no one talks about.

Are there any fridgies on here that have seen any galvanic corrosion in cool stores made of this stuff?

Originally Posted by loanrangie

Don't these panels come in aluminium ?

Yep, looked at them until I saw the price.

Products — ALSIPS

The price in the table in the "Weight and cost" section of this website for Steel SIPs is pretty well bang on (I have been quoted $54 per sqm of panel + GST) so can only assume the price for Ali SIPs is correct too.