Is it possible to use a C - Purlin as a structural spline? Or do the panels always sit on top of the purlins?

Are thre any companies that produce C - Purlins that are foam filled that can be used as splines for high load situations? Or even open web steel splines - or steel I beam splines? Just as an alternative to TJIs.

If the splines have enough structural strength, maybe you could even use less expensive 4' x 8' non strucural panels between them.

Just throwing it out there.

NHSIP&ICF,

You certainly got a lot of good input in this thread. I thought I'd add my two cents. I'm not familiar with too many of these guys, I do know that you can't go wrong with any advice panelwright gives you.

An 80lb snow load is kids play. I don't see any reason why you would have to use a dimensional lumber spline (I'm not an engineer, but I play one on T.V.). An Insulated I-Joist should be fine. Premier Buidling Systems provides those as well as I saw somewhere above that Enercept does also.

A general overview of roof splines:

Surface splines have become a thing of the past. The industry has pretty much moved to the "Super or Box Spline". Surface splines are a major pain in the ass to use on a roof set as they are flimsy and get caught up. You end up shutting down the roof set as guys yell at each other from on top of the roof to the guy on the ladder below the panel, with a third or fourth guy prying, dashing ot the truck to pull out the come-alongs, guys setting up using SIP Jacks, others pounding with sledge hammers and a whole bunch of sweat running all over the place. Throw those surface splines away !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

The Super Spline slips right in. No pounding, no screaming, no sweating. If you're really smart, you order your super splines as 4 x panels to any length (if your roof panels are 20 foot, order a 4 x 20 panel) and cut your own splines. Even smarter to order the Super Spline 1/8 inch undersized than the core of your roof panels. Your roof package will go together like butter !

The next choice, if your engineer won't allow Super Splines is an Insulated I-Joist. One of the coolest thing that Premier did was to size the top and bottom chords of their I-joist to be 3 inches. That was brilliant! It standarizes all edge setbacks. There usually are some areas in the same roof where there are shorter spans and you don't need the I-joist, where you can use a Super Spline. Same setback for both. Another cool thing is all your roof panels get ordered with 1 1/2 setbacks, so you don't have to order different panels where an 1 1/2 dimensional subfasica is to be installed. I have found Premier to be on the leading edge of innovation with their SIP products.

Lastly, we get into dimensional lumber. It does have it's thermal bridging issues that will show up as lines in an asphalt roof. No problem with other types of roofing. Ideally, a 1 3/4 LVL would be my first choice, then a 4 x my last. As it was stated in one of the earlier posts, there were problems with a crowned member causing installation problems. That problem was with the fabricator, not the spline member. You simply can't use crowned or twisted 4 x splines in any roof panel. When we do have to (use dimensional lumber, we do it kicking and screaming) use 4 x spline stock cause some cya engineer would not have it any other way, we special order our 4 x stock and yes, we do pay a premium price. Ends up costing the same as if we bought LVL stock.

No matter what spline stock you use, the most important aspect of roof packages IS THE SET !!!!!!!!!!!!!!!!!!!!!!!!!!!! You have a crane that's costing you anywhere from $ 95.00 to $ 175.00 per hour. You have 5 to 6 guys collectively costing $ 150.00 per hour plus and you usually have a group of interested potential customers watching. That roof needs to go together like butter.

We set an average of 2,000 sq. foot of simple gable roof in an 8 hour period. Cut up hips of roofs or roofs with several dormers, we still average around 1,600 sq. ft. a day. Splines are an important factor to hit these averages.

The Panel Guy

Panel Guy,

How do spline the hip roof joints?
Is any special treatment required where the spline between the panels meets the hip spline?

Very respectfully,
Larry

Larry;

super splines won't work on a hip or valley


TP Guy;

Explain to us what to do when our plans call for a 31 ft. roof panel?

Larry;

I have the steel hip/valley detail available which is receiver assembly rather than a "beat -in - place" spline with sweat rolling off you., I can send under seperate e mail file to any one who wants it, file is too large to post

cmkavala,

You've stirred my interest in steel SIPs. I'll be looking into them in more detail. I am an old(er) dog, but I can learn new tricks.

In hips and valleys you're required to use dimensional lumber due to a crushing issue at the edge of the panel, when installing the screws.

With OSB SIPs, you can't span a 31 foot distance. You would need a midspan support. Are you able to make that span with a steel SIP ?

Are you the only steel SIP manufacturer in the industry ?

I frequent most all of the national builder and product shows. I see a lot of good products and I've learned that one of the first questions to ask is tell me about your distribution. I live in California and it's surprising how so many of the new products and products in general have no distribution in our state. Most new products are pricing when they first come out cause they don't have the sales volume and to have to pay 3 to 4,000 in shipping to get it out here, simply doesn't pencil.

TPG

TPG;

Old!........ I have five grandchildren (two -15 years old)

My background in my younger days was always wood construction, trusses, panelized walls and commercial modulars.

Yes, I am familiar with the OSB connection details, drop me an e-mail and I'll send you the steel detail

an 8" steel SIP would span 31 ft. with a light roof load, but in most cases with 6" panels you would still need and intermedtiate support.

 But, the point I was trying to make is that you don't need to deal with the butt joint, which also makes it possible to use exposed steel panels as the permanent roof (up to 53ft.) if you don't mind a plain white roof.
In Florida roofs are required to have a secondary water barrier ( not felt!) under the new code. Therefore builders now need to install a peel-n-stick membrane under the roofing , with steel SIPs it already done!

I personally see no beauty to the roof but, in certain affordable housing or commercial applications where aesthetics are not as important. It makes economic sense. We have build many small warehouses, shops,homes, apartments & accessory structures left all raw. Some have been exposed to the elements for over 15 years with no problems.
But if you are mfg. of OSB SIPs your not about to give it up. But, I will say - I don't understand why someone on the west coast hasn't jumped on the steel sips band wagon, they have a great advantage in areas where wild fires occur.
There are at least 20 steel sip manufacturers thru out the country and at least 5 in Florida
I am not a manufacturer, I distribute thru our other company SipDepot.com for a manufacturer that does not want to deal directly with the consumer. We strictly buy raw panels and package them up with all the other parts and accessories. If someone wants an erected shell (southeast US) or a turnkey project (Tampa area) we do supply and installs thru Marquis Construction  & Development, Inc.

I will be at the 2009 IBS in Vegas next January to promote steel SIPs construction.
The Metalcon show is better place to find steel panel products and the show only takes 4 hours to get thru