...that is the question. Well, maybe if Shakespeare were building a SIPS house. In my talks with folks who have a product to sell, I have heard vociferous advocates for both site cutting and factory cutting of OSB SIPS. The former stress how necessary field adjustments are easier and the puzzle piecing of components can slow things down. They also state that you pay extra for the factory to do the cutting so the saving may be minimal.

The latter claim that the close tolerences of factory cuts make for a better structure and ultimately a faster build.

Is there a sense here that one technique is better than the other? By better I mean the final cost of the dried in envelope.

As always, thanks in advance for your thoughts.

Scott

Scott,

As another old saying goes, time is money. In my opinion, the faster you can get dried in, the better. Here are some of the advantages for having the factory rough in the windows and doors.

1. Faster dry in time
2. Headers supplied for bigger windows
3. Less waste material to throw away
4. Eliminate window layout mistakes
5. Tighter fits around windows and doors
6. Better chance of level, square rough openings
7. Don’t need special saw to cut out windows and doors

The only advantage of doing it yourself that I can see is you may save a little money. But by the time you take laying out the rough openings, purchasing or renting a special cutting saw, saw out the openings, cutting back the foam for the framing lumber, hauling all the scrap to the dump and repairing any errors, the savings would be very little. If the factory makes a layout mistake, they send you a new panel, free. If you make a mistake, you buy a new panel and you pay for the shipping. Also, say for instance it takes 1-1/2 hours to complete the window preparation, and you have 25 windows. That comes out to 37.5 hours (basically a week), and your time is worth $30 an hour, it would cost you $1125 to do it yourself. Then you would have to spend a few more days installing the windows. This doesn’t include special saw costs and time to clean up the site and time to run to the dump. If you decide not to get a special saw and use a circular saw to make the cutout, it will take about twice as long to make the cutout because you would have to drill holes at the four corners of the window, layout both sides, cut one side at a time, then using a saws-all, cut out the foam. If you have an extra two weeks, don’t have a construction loan that you have to make interest payments on, aren’t afraid of making an expensive error, a truck or trailer to haul 25 30”X48”X6-1/2” chunks of scrap to the dump (they won’t burn) then it might be cheaper to do it yourself. A lot more work, but cheaper. It may not be cheaper if you have to make one more interest payment on your construction loan than you have to.

Steve Etten
[email protected]
www.GrandCountySIPs.com

Steve;

Many of your points are valid if being done by a DIY, but not necessarily true if cut on site by an experienced crew.
One factory delay or oops gets extremely expensive with a whole crew standing around

Chris,

Is it that much cheaper to cut the panels onsite with a crew than having the factory cut them? I won’t say it’ll never happen, but I’ve never had a window the wrong size or in the wrong place working with a couple of different manufacturers. I have worked with CNC machines for about 15 years, and I don’t recall one making a mistake. Anytime there is a mistake, 99.999% of the time, it’s a human error. The process at the factory is to program the CNC machine to cut the panel from the blueprint, and then a quality audit person will check the panel against the blueprint. Like you said, it’s just too expensive to make mistakes. It does happen, but it’s rare. I have to admit there are some factories that are just plain sloppy in their programming, but I think overall, that’s improving. And, cutting on site does result in a fair amount of scrap and it’s resulting expense to remove.

I saw a SIP house nearby that had the windows cut on site, and it took almost 3 weeks to complete. To be fair, the crew consisted of one guy, so he had his hands full. I guess the best thing to do would be compare the costs of an onsite crew plus the removal of scrap vs. the cost of having the windows roughed out at the factory. How many hours does a crew of how many take to cut out 25 windows onsite? I’ve never done the cutting onsite, and I’m interested to see if there is a substantial savings. Thanks for your time, Steve

Steve Etten
[email protected]
www.GrandCountySIPs.com

Scott,

Out of curiosity, I called my factory rep and asked him what they charge to cut out a window. He told me they charge $1.50 a linear foot to cut it out and scoop the foam back for the framing lumber. So, for a 3’X4’ window, the charge would be $21. So, roughly speaking, for 25 windows it would cost you $525. Also, the shipping charges may be less because most shippers charge by the pound. And, no scrap to haul to the dump.

Steve Etten
[email protected]
www.GrandCountySIPs.com

Chris,

I've seen pictures of the tooling to cut OSB SIPs; I don't have it in my shop, but none of it is significantly different from what I've used before.  I've done littel metal work, but I've used hand shears and nibblers -- neither of which would seem to translate to cutting a 3D SIP. 

What tools do you need on site to cut openings in steel SIPs and, if necessary, dress the edges?  Is it something beyond the realistic ability of a carpenter -- is it necessary to hire an experienced and equiped team to erect the shell?

Very respectfully,
Larry

The 'Puzzle Piecing' argument seems a bit weak.

Hmmm, there are still some manufacturers and fabricators that are manually cutting the panels.

I think it boils down to:

• Your local cost of labor...
• The complexity of the structure...
• How much lumber needs to be added...
• and, your need for a quickly 'Dried-In' structure...

To be sure, prefabbed(with lumber already installed) SIPS will save you onsite labor, and the structure can be completed quicker. OTOH, if you are DIY, not in a big hurry and obtain some training, you'll be able to save a few bucks.

Personally, unless it's a very simple structure, we will use prefabbed SIPS.

Most SIP shippers ship by the loaded mile

the following link is the panel saw we use for cutting steel SIP skins:

link
or ..... they do loan out (with deposit) saws to people buying panels
blades are about $5.25

you do not need to dress edges they are picture framed out with steel  channel

Both jobs below are Do-it yourselfers: the first one's day job is a building inspector for the city of Sanford who is helping to build his daughters house

link

the next is New Tribes Missionaries, Sanford, Florida...doing onsite cutting and erecting this duplex shell in less than 2-1/2 days. They had absolutely no SIPs experience.

link
They have been so impressed they are now planning a 9,000 sq. ft. worship center with steel SIPs. They will also build the worship center with all volunteers

Thanks Chris -- that's a whole lot more straight forward than I'd envisioned!

Larry