Just looking for a quick opinion here. I am just recently seeing SIPs as a viable option for my project. I am planning on building my shipping container home and insulating it with either spray from inside a frame, or maybe SIPs? Is this a practical or cost effective solution for a 45' Steel shipping container that is a HIGH CUBE? 9'6" interior? I figured that the roof and the floor would really benefit from 6" or so SIP? Wallace http://Ecodale.blogspot.com

you may get other, more educated opinions on this, but I'll give you mine. I think you need an "IP" more than a "SIP". the shipping container is structural, so you don't really need anything that can support a load. I'm sure that wrapping the container with SIP panels would work, but I'm guessing there are more cost effective options.

So does that mean that IPs are cheaper than SIPs? Where do I buy them? Can I cut them to length myself? I am going to Youtube that stuff now. I should note that I am lining the inside of the container, NOT the outside. The outside will stay as is, that blue color you can see on the blog. Mainly I want to cover the floor, roof, and walls. Preferrably the floors and roof with 6" and the walls with something thinner to help save any of the 8' width that I can salvage.

Wallace
http://ecodale.blogspot.com

Posted By jeepingetowah on 21 Dec 2010 12:51 PM
So does that mean that IPs are cheaper than SIPs? Where do I buy them? Can I cut them to length myself? I am going to Youtube that stuff now. I should note that I am lining the inside of the container, NOT the outside. The outside will stay as is, that blue color you can see on the blog. Mainly I want to cover the floor, roof, and walls. Preferrably the floors and roof with 6" and the walls with something thinner to help save any of the 8' width that I can salvage.

Wallace
http://ecodale.blogspot.com

sorry for the confustion, I was making a bit of a joke.  No such thing as IP's (as far as I know..).  My point is that SIPs aren't what I'd call cheap, and part of the cost is the structural element.  Since you already have that in place, it'd be kind of like paying to frame your house twice.

Here's my thought -

The solid metal exterior should act as a air/vapor barrier (assuming that any holes are plugged when you start).  You're going to need framing to hang drywall & stuff anyway - maybe stud out the walls a few inches in from the outer wall & then use dense pack cellulose.  The space between the studs & the outer wall will act as a thermal break.  I'm sure Dana or someone more educated than myself will have ideas, but that may be a good cost-effective starting point.

Dense Pack Cellulose... eh? Is that like the really cool plant based version of Styrofoam? I was planning on framing it out. I visited a guy in Austin, TX that I put up an article on my blog. If you were to frame it out like this Alan did... would you spray foam or use some other type of insulation? Oh, and I am here cause I am clueless... so don't be surprised if I am like, WHA?

Link here = = = > http://ecodale.blogspot.com/2010/08/topic-discussion-insulation.html

Wallace
http://ecodale.blogspot.com

Actually, IP does sort of exist. It's called nail base if I recall properly. They use it for insullating roofs on the exteriour prior to putting the actual roofing material on.

Posted By jeepingetowah on 21 Dec 2010 10:11 AM
Just looking for a quick opinion here. I am just recently seeing SIPs as a viable option for my project. I am planning on building my shipping container home and insulating it with either spray from inside a frame, or maybe SIPs? Is this a practical or cost effective solution for a 45' Steel shipping container that is a HIGH CUBE? 9'6" interior? I figured that the roof and the floor would really benefit from 6" or so SIP? Wallace http://Ecodale.blogspot.com

So if you are lining the entire container....... why do you need the container?

I would think spray foam is your best bet. I've used the polyurethane spray (DOW froth paks - http://building.dow.com/na/en/products/insulation/frothpak.htm) for doing the inside of telecom vehicles. It does the best job of sealing, insulating and adding to the rigidity of the structure when space is a premium. Of course you don't need any added rigidity with a shipping container. Nailbase panels will most likely be EPS foam with a much lower R-value per inch (around R4 versus R7). If you are doing this yourself make sure you use the full body/head/eye covering and mask. Another place selling a similar product is http://www.tigerfoam.com/products.php (but I have not used them).

@cmkavala - Why? Because I felt that this was a green idea that was totally cost effective and STRONG, really strong, and would last much longer than most conventional materials. Stone or block might be really nice, but I don't know how to build that stuff. This cuts down on the things I will have to do, IMHO, to get this thing "sea worthy".

@Torben - I am off for the rest of the holidays, and I will spend time researching your ideas and links. Do you think that R factor will be such a big role in such a small space? Or do you think that it will be pretty easy in general to heat/cool 360 sq ft of space as long as it is insulated with a bare bones setup like that foam?

Thanks for any/all help, this keeps me motivated and pushing along.

Wallace
http://ecodale.blogspot.com

If you want to go cheap, wet-sprayed cellulose (not dense-packed) would deliver more R/$ but would take up more interior space since you're at ~ R3.6-ish per inch.

Closed cell foam gives you about R6/inch but at more than a buck a square foot (installed) for that R6. (R12 would be over $/ft^2, R18 would be$3+, etc.) Rigid-board polyisocyanurate also delivers ~ R6/inch at about $0.60/sq-ft for R6 (+ installation cost), and 3-3.5" 4x8 sheets of R19-R22 are commonly used as roofing insulation. Last time I priced it 3" fiber-faced iso was running ~$55/sheet f.o.b. the distributor's lot. In cold/very-cold climates it's better to de-rate iso to ~R5.6/inch from a design point of view since it's measured R falls somewhat with colder temps (unlike EPS and XPS which rises in R with falling temps.) In mixed or cooling dominated climates, use R6 or R6.5/inch for iso. A 3" panel would deliver ~ R19 @75F, ~R17 at 25F, taking up about the same thickness as a 2x4 studwall. If you went with 2" goods you'd be comparable in R to a 2x4 studwall with wet spray cellulose, and save an inch of interior on each side.

Cargo cans are inherently pretty air and water-vapor tight and are quite rigid, so the air-barrier, moisture control, and structural advantages that might make the price-premium worthwhile for sprayed closed cell in stick-built structures just aren't there. Similarly there's little advantage to densepacking an air-tight structure if you use wet-sprayed goods, which has adhesives to keep it from settling over time. Cellulose adds a bit of thermal mass which may have SOME performance advantage in places that see large daily swings in temperature, but probably not enough to matter if you're going with less than R20.

Nail-base iso works, so long as you finished it out on the interior with gypsum. IIRC the nailbase skins on most manufacturers' panel goods doesn't qualify as an ignition barrier for the foam in an application like this. Nailbase EPS is cheaper, but only ~ R4/inch @ 75F. EPS loses R at elevated temp/gains R at lower temp (better for cold than hot climates.) HunterPanels, and Atlas are the two manufacturers that immediately come to mind, but there are others. It'll never be found in home-center type box stores, but distributors to the commercial construction trade carry it (as well as the non-nailbase iso.)

@Dana1 - Thanks for all the info. I must admit that I am a bit confused... BUT... I see there are a lot of options. For me I hoped to use either plywood for the walls, or maybe some of that whiteboard stuff that they have at the home store... so you can write all over the walls, and they are easy to clean. At least until the time comes when it is necessary to upgrade to drywall... but I hear that stuff is not so easy at first to hang.

So just to clarify... if I stick build the inside of the container with 2 x 4s so that there is a place to put insulation and then cover over it with whiteboard or with plywood, what is your best suggestion for Austin, TX climate. Not too cold in the winter, but pretty hot in the mid summer. If I can avoid spraying... that is preferred. I honestly hoped for something like styrofoam in shape, texture, and easy installation. Was that one of your options? (not styrofoam but rigid like that)

Wallace
http://ecodale.blogspot.com

@Torben - are those spray options toxic? I mean if you have to wear such a crazy suit to install it... does that mean it is safe to live around?

Wallace
http://ecodale.blogspot.com

Posted By jeepingetowah on 22 Dec 2010 11:30 AM
@Dana1 - Thanks for all the info. I must admit that I am a bit confused... BUT... I see there are a lot of options. For me I hoped to use either plywood for the walls, or maybe some of that whiteboard stuff that they have at the home store... so you can write all over the walls, and they are easy to clean. At least until the time comes when it is necessary to upgrade to drywall... but I hear that stuff is not so easy at first to hang.

So just to clarify... if I stick build the inside of the container with 2 x 4s so that there is a place to put insulation and then cover over it with whiteboard or with plywood, what is your best suggestion for Austin, TX climate. Not too cold in the winter, but pretty hot in the mid summer. If I can avoid spraying... that is preferred. I honestly hoped for something like styrofoam in shape, texture, and easy installation. Was that one of your options? (not styrofoam but rigid like that)

Wallace
http://ecodale.blogspot.com

The most common rigid foams are EPS (bead-board, sometimes with foil or poly facers), XPS (smooth, usually colored), and polyisocyanurate (aka "iso", sometimes "pir", usually with a fiber or foil facer) all panelized goods, easy to cut with hand tools.

What most people call "styrofoam" is EPS (expanded polystyrene)- it has a beaded macro-structure, looks like a cheap-cooler or coffee cup, and is usually white.  Styrofoam is a trademark of Dow for XPS (extruded expanded polystyrene) which is smooth in macro-texture, and the most commonly available in Dow-blue or Corning-pink, but there are also other manufacturers & colors.  Iso is a pale yellow color- almost white when new, and softer than the others, somewhat brittle, and usually sold with protective facers, which can also be vapor retarders. Foil faced iso is commonly available at box-stores, as is foil or poly faced EPS, and un-faced XPS. Fiber faced an higher-R foil face iso or thick EPS is usually only found at commercial construction distributors.  Low density "Type-I" EPS is the cheapest per unit R, but not the best choice for cooling dominated climates unless you're going to R40 or more (which would be 11" thick for Type-I).

If you use plywood or OSB on the interior, most 3/8" goods or thicker would qualify as an ignition barrier for foam. If it's sheet-rock type gypsum wallboard (chalky interior, paper facers) you'll need a minimum of 1/2" thick goods to be legal.

Putting up rigid foam in a cargo can it's better to glue it to the steel first (with foam-board construction adhesive- available at box stores), then trap it with any framing or furring to hold it in place permanently.  That way you don't end up with the thermal short-circuiting of the studs, which are only ~R1 per inch. The difference in performance by going with a full thermal break (no studs penetrating) is DRAMATIC, and by not having to cut & cobble your way into stud bays it's a lot less labor, with fewer seams & gaps. (Foam seal those with 1-part foam as you go, trim the excess.)

If you use finger-jointed 2x3s instead of 2x4s they'll be straighter/better than regular milled 2x3s, which are often pretty twisted or warped.  Better yet, using steel studs or furring you'll get a perfectly flat interior, and since it's not spanning the insulation, won't present a thermal-short.  Either way, if you went with say 2" of iso (R12), and a 2x3 studwall with R8 fiberglass or rock-wool batts, or spray cellulose in the stud-bays, it would perform to about R17 (steel 2x3 studs) or R19 (wood 2x3 studs) when you're done.

In Austin, go with iso for the rigid foam. The styrene based XPS or EPS crap-out pretty fast in R once you're well above 100F for surface temps on your exterior steel.  Foil faced, fiber faced, it doesn't matter if the wood is all on the interior of the thermal envelope. If you use batts rather than cellulose in the stud bays use only unfaced batts. If unfaced R8 is unavailable, you can put the facer on the exterior side, against the foam.  Price it out against unfaced R11 or R13 batts designed for 2x4 construction though (sold as un-rated soundproofing batts sometimes). Compressed into a 2x3 studwall it won't yield it's fluffed-out R but it'll be pretty close to R8.  If it's cheaper/easier than R8 econobatts with facers, so much the better.

In Austin, an ~R20 clear-wall with heat-rejecting "cool roof" type paint on the exterior would perform pretty well, winter & summer.  But don't forget to insulate the floor too (to at least 1/2-2/3 of your wall's R value), and putting R25 or more of iso + fiber on the roof would not be overkill.  On the floor you can get away with EPS, since it'll never get direct sun, and will be moderated by the earth temperatures ('ceptin' maybe after the hurricane knocks it over in which case you probably won't care )  A 2.5" layer of Type-II (mid-density) EPS would deliver an unbroken R10, and with 5/8" or thicker t & g OSB or ply as subflooring on top can easily handle residiential floor loading without compression. If you can, float it- no through-fasteners to the floor steel for the fewest thermal bridges and it'll perform well.  Anchor the subflooring to the studwalls at the edges, and only bolt the top/bottom plates of the studwalls to the exterior skin.  The bottom plate of the studwall should be resting atop the subfloor & insulation, but through-bolted to the steel of the cargo can every 3-4' or so.  You can also use XPS as floor insulation, but iso may have issues with compression over time in a floor application- you'd have to assess it more carefully than a web-forum response would allow to know for sure.  EPS is cheaper anyway, and the difference in headroom loss between two is only about an inch at R10.  XPS has similar compression ratings to Type-II EPS, and you'd hit R10 at only 2", but it would be more expensive.

Posted By jeepingetowah on 22 Dec 2010 10:01 AM
@cmkavala - Why? Because I felt that this was a green idea that was totally cost effective and STRONG, really strong, and would last much longer than most conventional materials. Stone or block might be really nice, but I don't know how to build that stuff. This cuts down on the things I will have to do, IMHO, to get this thing "sea worthy".

 a 8ft x 9 - 6 x 40 ft. built entirely of SIPS would be 3 times stronger than frame, would probably be cabable of wind loads in excess of 200 mph. without the container, so  why would you need to go to the expense of buying a container?
If you want to be green........ recycle the container

The suit for the spray foam is little more than a paper suit. It is not a matter of toxicity, especially once the foam has expanded and cured. As far as air-quality goes I would far prefer foam insulation over fiberglass particles that can get into the air you breathe. Spray foam also does a wonderful job of sealing all your leaks. Air leaks are usually a bigger hit on energy efficiency than amount of insulation. Please note if you do a good enough job sealing leaks you need to make sure you are getting enough fresh air. I would much rather bring fresh air in, in a controlled manner, than depend on leaks through fiberglass insulation, mold, etcetera. Polyurethane spray foam is essentially a glue that expands as part of the chemical reaction as the two parts are mixed. Before the foam dries there are fumes you shouldn't breathe. The foam will stick to virtually anything it touches before it dries. You don't want it sticking to your skin, clothes, or especially your eyes. We only wore the suits, mask, and eye wear while spraying, not when shaving the excess cured foam.

If you're looking at foam boards the following is a place for recycled foam board (but it may be difficult to get quantities for less than 100 containers).
http://www.insulationdepot.com

I would think more important than R-value is the extent you minimize thermal bridges. The container is very efficient at transmitting outside heat to the interior. Shading the container would certainly help. Use the least conductive materials for the framing of the container walls/roof/floor and minimize the more conductive materials you have to use (steel is more than 30 times more conductive than steel). Also try to minimize thermal bridges around windows as well as the amount of windows.

The raw interior width of your container is 7'-8". That's not very much width for living space. You should try to preserve as much of that width as possible by using the highest R- value insulation and shallowest wall framing. A PU spray foam is probably the way to go at R-6/7ish per inch. So, 2 inches of it will get you to the minimum for code for the walls. Use 2x3 studs for your wall framing and you will have 2.5" of insulation thickness. You will actually have more depth to the insulation because of the corrugations in the container walls. Add a layer of drywall and you've only used up 3" of width each side giving a finished interior width of 7'-2". By the way, for code, a 'habitable' room cannot have a dimension less than 7'-0". I'm just citing code to give you a perspective on what your local jurisdiction may look for.

Actually, to gain another inch of width, turn your studs flat to the walls and space them 1/2" off the walls giving you a 2" depth of framing and the foam will fill in behind the stud and reinforce it and also give you a better thermal break. Every inch counts...

Wallace, sorry if I've missed some of the story because I think I remember you from another thread, but why are you insulating the inside instead of the outside? Put several inches of your favorite foam on the outside, then cover it with a polymer modified stucco.