I've been designing a new home and have been very interested in using SIPs for many elements of the structure, but I have several concerns about their lack of a track record.

One crucial factor when considering SIPs is conspicuously absent from every SIP manufacturer's web site - design lifespan.  (at least I haven't been able to find it anywhere)  How long are SIPs expected to last?  When SIPs are constantly lauded as the next huge green building technique doesn't anyone consider one of the biggest "green" considerations; how long the structure will last?  The only mention I've seen of a design lifespan was on a manufacturers site where they say that standard new residential construction has a typical design lifespan of 60 years and SIPs comply with this.  That's not so great.  I live in an 80 year old house that could probably stand for another 100 years, so why all of a sudden are we building disposable buildings and calling them "green"?

I'd appreciate a response to this from an SIP manufacturer.  Do EPS or PUR panels last longer?  What types of testing have been performed to determine the usable lifespan of an SIP?  How long could an SIP structure conceivably last?  What is first to go?  The foam?  The adhesives?  OSB?

-Spencer

Spencer,

I have asked the very same question in a prior post. The replies were pretty much as you stated. Considering the materials themselves if the envelope is absolutely protected from moisture it should stand for some time, I would think at least 100 years. The EPS and PUR panels differ in that with PUR product the PUR is itself the adhesive. The EPS requires adhesive coating which brings in another element to the equation. As you are well aware if the SIP delaminates there is nothing to support the structure. This is a difficult element that we have to get over in considering SIPS. But I believe they are the future and with proper construction practices I cannot see what they would not last as long as any other wood framed home. Again, moisture control (and termites) are key.

Leonard

Spencer;

No track record?  it's been around about 60 years sonny!, DOW  first developed sips similar to the OSB type we see today.
Insulated doors, insulated overhead doors, RV structural walls, insulated truck/van bodies, refrigerated warehouses and walk-in freezers are just a few examples of SIPs technology.

We like to use steel SIPs and accelerated aging tests show that they will last at least 300 years. A styrofoam cup in a land fill takes about 300 years before it starts to degrade
The 60 year life span you mentioned is for conventional 2x4 construction and not for SIPs.
I'll bet that 80 year old  house is real state of the art when it come to energy efficiency.
I can not respond to the PUR product except to have you visit this link from a manufacturer that says they are not suitable for construction the following is a statement directly from their website:

"One of the best insulating materials available so far is rigid polyuretahne foam (P.U.R.). PUR foam however has not been extensively used in building construction due to its poor tests properties on flammability, thermal stability and smoke developed, as compared to other heat insulating materials.PUR foam also do not meet building application safety requirements of most countries."


Ultra Panel

Spencer,

What materials were used in the construction of your house? Most houses built 80 years ago would be showing severe signs of aging if they weren't maintained well. I think that maintenance of any structure is the only real means of extending it's lifespan. With SIPs, I would think that the most serious problems would involve insect damage, and delamination. Others here could probably give a better assessment of that though.

Keeping insects away is mostly a maintenance issue - contracting with Terminex. Delamination would probably be more of a moisture issue. Over time it may become evident that delamination is more of a problem than it appears to be, but someone will probably come up with a way of dealing with that problem as well with some apparatus for for field applying some adhesive to correct the problem.

Ultimately, my experience has been that any structure is capable of extended lifespans (as long as they can withstand acts of god) as long as they are maintained well. My house was stick-built in 1924 out of redwood. It was extensively maintained over the years, and is probably in the same (or maybe even better) shape than when it was built. It lies on the bank of a creek in the middle of a redwood forest - which is one of the least hospitible environments for a house, but it will probably easily stand for another 50 years as well.

Dick Mills

I have read that PUR out performs EPS in every category including fire.

Polyurethane Vs. EPS (Expanded Polystyrene)

[i][b]Fire Resistance[/b] - The polyurethane that we use is a UL Class 1 rated foam. This means that our polyurethane is nor a source for fire. On it's own, our polyurethane will not burn. When left on it's own, it will extinguish it self. A Class 1 rating is the highest rating a building product can obtain. Also, polyurethane is a thermal-set plastic. This means, that it will not melt. Our polyurethane is not affected until temperatures reach 1000 degrees and at that time it will only char. EPS on the other hand is not a thermal-set plastic and will begin to soften at temperatures of 180 degrees, and melt at temperatures of 240 degrees. Polyurethane has a distinct advantage.[/i]

slenzen;

you forgot to mention that PUR off gasses for years after installation, is an irritant to the skin, eyes and nose while cutting. Srinks as it ages
have also seen a higher incidence of delamination with PUR panels and for whatever reason insects like it better too.
If your are in a house and its over 180 degrees you are dead anyway!

Tsk, tsk, Kavala.  Could it be that you are vested in EPS as the insulating material?  Melting at 180 degrees is less a matter of fire survival than fire damage - - you know that.  Each product has its merit and demerits.  Lets help to illuminate and educate rather than slammingcompeting products.

eastsound

eastsound;

These forums are for everyones education and are read by newcomers & builder-owners. In my opinion, I read a lot of mis-information and half-truths on the posts
No I am not vested in EPS, but base my comments on past experiences with both products, it is great that slenzen posts the benifits of PUR directly from the supplier rather than from third party source. I have only pointed out the disadvantages of those products based on my hands-on experience.
It is not slamming, it is illuminating ............... and depending on the source the EPS melts at 240 not 180 degrees
While I am passionate about what we do, I would always give a frank honest opinion about all the SIPs product that are on the market. I keep my mind open and am always searching for the next best thing. I have no ties to any one product. Just don't get me started on ICFs!

I'm here trying to collect some facts for an upcoming build. Not to push one system over another. Let the pros and cons fly!

Chris,

What adhesive do you guys use to attach your the skins to your EPS cores?

Dick Mills

Dick;

Spec as follows;

" Manufactured According to ASTME-72 Standards
   lamination w/ Voracor Adhesives (dow chemical)
   Part A - CE130 ISO
   Part B - Cs 1075 Polyol"

Chris,

If I am not mistaken, all of the Voracor adhesives are Polyurethanes. One would think that if a PU panel is more likely to delaminate, that you wouldn't want to use a PU adhesive for EPS cores.

Dick Mills

Dick;

I am not a chemist, but if you have more insight into the chemical properties of the adhesive, please share with us what you base your information on.

Chris,

Dow can probably provide you with more information than I can:

http://www.dow.com/pusystems/apps/index.htm

Dick Mills

Dick;
Thats great info, and I have been to the website, but can you tell which one it is?

Chris,

I haven't been able to locate any specific information for a CE130 Cs1075 Polyol, just more generic information from Dow that seems to indicate that all Voracor adhesives are PU systems. You can probably put your hands on an MSDS or data sheet that would confirm or refute the point.

Dick Mills

Dick ............................

PRODUCT INFORMATION

1881 West Oak Parkway

Marietta, GA 30062

1.800.735.3129

System :

Voracor

®

CS

1075

Polyol

Voracor

®

CE

130

Isocyanate

I. Description :

A two component  rigid foam expanded with water.

Suggested Application :

Foaming adhesive

II. Typical Chemical Properties

Component

Mix Ratio, by Weight

Specific Gravity

Iso

100

1.26

Polyol

54

1.02

Reactivity

Gelation

00:09

-

00:22

Tack Free

00:18

-

00:33

III. Typical Physical Properties

Property

Values

ASTM Method

Density, Free Rise (pcf)

1.90

+/-

0.2

D-1622

In Place Density, Core (pcf)

2.20

+/-

0.4

D-1622

In Place Density, Overall (pcf)

2.40

+/-

0.4

D-1622

Closed Cells, %

D-2856

K - Factor, Core, Initial

[BTU - in/(hr*sq.ft*deg F)]

C-518

Demensional Stability (% Volume Change)

28 Days

D-2126

Humid Age

Dry Heat

Cold Age

Compressive Strength, Parallel (psi)

D-1621

Compressive Strength, Perpendicular (psi)

D-1621

This information is provided for use by skilled persons who assume the risk of selection of materials, processes, and equipment. The final decision

to use or implement the product remains with you and is subject to your decisions as to any testing that may be needed. Because Dow has no

control over any aspect of your operations no warranty of any kind is given regarding these recommendations or the quality of the end product.

Please observe any instructions or warning on container labels - they are important and are not modified by this communication. No freedom from

any patent is granted or to be inferred. The Dow Sales Contract terms and conditions continue to apply.

® Trademark of The Dow Chemical

2/5/2002

Thanks Chris,

So, it is a polyurethane - and not just an adhesive, it is a foaming adhesive with similar density to the PU foam used in most PU panels. Polyols mixed with Isocyanates produce polyurethanes. There are urethanes which are not polyurethanes, and some of them are exceptional adhesives. Polyurethanes are also exceptional adhesives, which makes me a bit leary of claims that PU panels delaminate more than EPS panels.

Dick Mills

Dick;

It has been my experience when removing steel skins for window openings there is little adhesion with the PU panels. Now why that occurs, I do not know. There could be other factory conditions during manufacturing that are causing the problem: oil film on steel, condensation on steel, too hot, too cold, high humidity, low injection pressure. Who knows?
Delamination is just one of the factors that have kept me away from PU panels and leaned me towards EPS

Chris,

With all composite materials the manufacturing process needs to be closely monitored and maintained to achieve the desired results. You need the right quantity of material; it has to be held under the right pressure to ensure the proper density; and the proper mix ratio of raw materials. That is true for EPS as well as PU. But that is entirely a manufacturing QA issue, and not an issue related to the use of PU - which is very well illustrated by the fact that even your EPS panels use PU as the adhesive layer. It would be nice if there was only one perfect material for every application, but generally there are several with their own set of pros and cons.

And I realize that you are in the business of selling a product to your customers where you need to convince them (and yourself) that they are getting the best possible solution. But the fact of the matter is that there are several equally "perfect" solutions.

Dick Mills