Talking about SIPS

[ljmathias]

Wow, great explanation... pictures would be nice ???

What kind of wood do you use for the strapping- big box or rough cut and/or air or kiln dried?  On a two story, do you butt joint the strapping on the walls, staggered or all aligned?

What do you use for soffit and facia?  My most recent small house is pretty rustic looking so I used PT pine on the facia (actually looks pretty good in contrast to the off-white metal roof) and hardi board with holes for the soffit plus wood trim that will blend in with the pine siding I hope to start today.

Lj

[moonhill]

Strapping is spruce or pine, raw, right out of the mill yard(my mill yard), typically 5/4" I counter sink the screw to adjust how far into the planks the screws go and to flush them with the straps.  I do not cover the horizontal seams just fill with foam, the excess is trimmed if it protrudes beyond the strapping.  On a tall building the strapping would be continues.  I do use large 3" washers and shorter screws as well in these areas to temporarily hold the final layer in place, that is between the strapping near the seams.  Usually 8' sheets don't run up all the way, you are always trying to extend below the floor level and make it to the underside of the roof thus stretching the run to 10' or so on a single floor house.   

Tim

[Thomas-in-Kentucky]

What did you use to fasten the oak batting?  Stainless screws or regular nails?  and what did you drive through the simpson brackets to your purlins with?

Nails...  #16 galvanized nails to hold the simpson brackets to the purlins.  needed 16's to get through the t&g all the way to the purlins.  Don't buy "box nails" - they bend too easily.  The hole in the brackets might be slightly smaller than the 16's, but its no harder to nail them thru the small hole than to nail them into oak.

In the same aisle as the brackets, they sell #9 nails (galvanized) or some such weirdness.  That's what I used to nail the brackets to the 2x10s.  About the dia of a #16 nail, but only 1.25" long. 

I think I used spiral galvanized #8 nails to nail the oak battens to the pine.  Maybe I used a bigger nail - can't remember.

In all cases, the nails are "hot dip galvanized," not the crappy electro-galvanized.  Half the nails in my roof are made in USA, the other half in China.  Lowes switched as I was building my roof.  The price went up, not down.  Go figure.  It was possible for some time to sort through the boxes and find made in USA at Lowes, and I bought out the supply of made-in-USA at our local HW store.  After that, it was practically impossible to get anything but Chinese.  Packaging was identical. 

One other sad thing... when I finally gave in and bought the Chinese drywall screws (the big manufacturers switched over just like the nails), I noticed the quality seemed to be a little better.  We're in trouble.

My slate nails are smooth shank stainless.  Copper was almost impossible to drive into oak.

[moonhill]

Speaking of China, did you hear about the sulfur in the dry wall they shipped to the US?  It is bad and the insurance companies are not going to help.  Some people are going to have some stinky homes. 

Tim

[Thomas-in-Kentucky]

I heard something about that, but didn't follow up... do you have a link?  From what I understand, gypsum is some kind of byproduct of coal fired power plants, and we have lots of coal plants around here, and so we have locally manufactured drywall.  I think most of my drywall was manufactured within 150 miles of here. 

BTW, there's a lot of Chinese slate being sold in the US under domestic labels - buyer beware.  Some of it good, some of it total crap.  All of it made w/o much regard for human rights.

[Hilltop366]

"In the same aisle as the brackets, they sell #9 nails (galvanized) or some such weirdness.  That's what I used to nail the brackets to the 2x10s.  About the dia of a #16 nail, but only 1.25" long.  "

I think these are the nails we call "joist hanger" nails.

Thanks for the "wrap and strap" descriptions I think I got it now, The part I did'nt get was what all of this was fastened to but after rereading it I take it that you enclose the timber frame with planking first then do the wrap & strap.

If so then I get it,

If not then I don't.

[moonhill]

Yes the frame is planked over, it is the base.

Tim

[wkheathjr]

I'm glad that Brad started this topic because I was wondering the same thing myself.  And I am sorry if I change any subject but it is technically related.

I spoke with a lady who wanted to build a TF home in the mountain and when I mentioned my plan of using SIPS, she seems to be opposed to the idea of using it on her house mainly because she was concerned about chemical materials being used to make SIPS?  She said she rather to use "cob" which is a mix of sand, water, and straw.  And to add more R value, simply add sawdust to it.

But I am really curious about the chemical materials she was concerned about.  Anyone has any idea what type of chemical is used in it that could affect the housing?  Like Brad said, maybe it is good for 20-30 years but what about 50-70 years?  Remember Lead?  It was thought to be ok 30-40 years ago and is now banned from all buildings especially with schools.

I hope I haven't thrown any wrench in the gear but I hope that this would be interesting topic to debate?

[Brad_bb]

I'm guessing you mean outgassing when you say chemicals?  I wasn't referring to that at all, just longevity of the foam.  I think the foam itself is pretty safe, that just leaves the adhesive in the OSB, and the adhesive to glue the pieces together.  I guess you'd have to request and MSDS sheet from the manufacturer.  I'd think these things are pretty stable and inert once cured.  SIPS have been around in the building industry for at least 30 years now.

[wkheathjr]

Didn't know it has been around for about 30 years now but that helped to know it.  I did a little research on it last night after posting my message but my eyes started to get sleepy so I got off and went to bed...  I plan to do more research on it just for my own curious, that's all. But up to this point, I would say I would go with polyurethane SIPS.

[Brad_bb]

Without knowing prices or some of the other details we discussed, that's the way I'd lean.  Although Tyson up in Alaska just insulated his barn roof with a soy based expanding foam and he had some interesting points.  He stated that poly will lose some R value over time.  I'd like to find some info about this, does it lose, how much, over how long, does it only lose a percentage?
He ended up filling his home made roof cavities with expanding soy based foam.  He was going to use poly, but time and temperature precluded the poly and he went with the soy based because it could be sprayed in at lower temps and he said that it doesn't lose R value over time.  Another question is, will the soy based expanding foam have the same or lower R value per inch than poly, and if so how much difference?  If it does turn out to be better and greener, you'd think a panel company would want to take advantage of it.

[Jim_Rogers]

Several years ago, we had a tour of a panel plant. They were gluing foam panels to osb. And pressing them to a standard pressure to insure the panel was made right.

The off-gasing from this gluing operation was only during the first 24 hours while the glue was curing. The drying process takes place at the plant and no panel is released until it is cured. Then there is no off-gasing from the panels.

They have learned from different methods and types of glues over the years and the industry has adjusted their formulas to prevent off-gasing at the final location of installation. Including the glue used in osb

As a result of their methods and their quality control they increased their guarantee of their panels from 15 years to 20 years.

They did show us, during a classroom setting, some pictures of panel failures. These failures were when customers called them back to review installed panels.

100% of the failures were due to improper installation which resulted in water getting into the outer layer of osb and allowing it to rot. So much so that now they provide flashing instructions for windows openings. If a window opening is flashed correctly then the water doesn't get into the panel and cause the rot problem.

It was a very educational event the tour and the classroom. This was by Foard Panel from NH.

Jim Rogers

[Raphael]

I went with Both!  :D

I've got Foard's XPS panels on all the walls and the office/shed roof, and the soy foam in my attic floor and upper roof where the entry bumps up.

[sperry]

Thomas in Kentucky couldn't have said it better, "don't use Thermocore". What a bunch of incompitent jerks. I had nothing but problems with their design staff and their Owner. They have absolutely no warranty. I just recently had to put on a "cold roof" after just 5 years. The seams in the SIP's stuck up so much I couldn't stand to look at it anymore. I have several other stories about them too but don't have time to get to it.

[Brad_bb]

Not to go off topic too much, but I'm still stuck mentally on how to detect if you have a roof leak when you have sips, as in a cold roof situation.  If it's leaking how would you know?  Won't it leak and rot your Sip osb and not know until its really bad?

[wkheathjr]

Just thought I would add this what I found and dunno if you guys already know about this?  I am consider taking the course just for educated purpose and possible make my own SIPs if the labor seems equal to TF labor.

SIP School

[trailman]

a friend of mine spent several weeks working on a house that had water damaged sips and termites infesting. i helped glue on new plywood and reside lower walls all around. not a fun job. he boxed in the bottom of panels with pt lumber. those little bugs go right through the panels like my nephews in a chocolate cake. never cared much for those panels with no real wood to nail plywood and siding to. if i were building new i would rather use the spray foam for instead of panels.b :

[ballen]

Regarding SIP chemicals, isn't the insulation a petrolium based product?  Maybe that was the objection in one of the posts above? 
I'd like to build my own timber frame shell with 2 layers of reclaimed barn wood with a vapor barrier and celulose (recycled paper) in between.  Will obviously have to frame some cavities to support the cellulose but maybe the door and window framing will be enough.  Has anyone ever done this?  If I can figure it out, my whole house will be from recycled material. Talk about green!

[Thomas-in-Kentucky]

Not to go off topic too much, but I'm still stuck mentally on how to detect if you have a roof leak when you have sips, as in a cold roof situation.  If it's leaking how would you know?  Won't it leak and rot your Sip osb and not know until its really bad?

Did anyone ever answer this?  Seems like a valid concern.  Personally, I think houses with attics are preferable to houses without attics for this very reason.  (my house, not having an attic!)

[Brad_bb]

Not to go off topic too much, but I'm still stuck mentally on how to detect if you have a roof leak when you have sips, as in a cold roof situation.  If it's leaking how would you know?  Won't it leak and rot your Sip osb and not know until its really bad?

This same question was the subject of an article in Scantlings this month, the Timber Frame Guild newsletter, by Rick Collins of Trillium Dell Timberworks.  Though he has been installing SIPS for years, he has come to the same realization about the difficulty in detecting a leak until you have have a massive failure of the material.  He also questions the long term sustainability of SIPS, noting that although they have their advantages, failures at say 50 years, are not as sustainable as a system that would last longer like older methods that use solid wood (higher quality materials), versus OSB, or cold roofs where leaks would be more detectable and more easily repaired.  Do the benefits of Sips out weigh the drawbacks of the system?

[scgargoyle]

If I were going to use SIP's in a build, I would go with steel SIP's. They're foam sandwiched with steel instead of OSB. There are no seams like conventional SIP's, where you would have a thermal bridge. Bugs and rot won't get them, and the ones I looked at have a finish that can be used for the siding without any other covering. They are used that way on commercial buildings. It would be an odd juxtaposition to use steel SIP's on a timber frame, I suppose.  :D

[addicted]

scgargoyle
Can you name some manufacturers of steel faced sips? That sounds very interesting.
Rusty

[Raphael]

I've seen aluminum clad refrigerator panels used on a residence once.
on "extreme living" or some show like it.

[witterbound]

Seems to me that steel SIPs wouldn't have the same structural value as OSB sips.  Is there any structural component to them?  If not, they would lose alot of their appeal, I'd suspect.