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Treated SIP foundation panels

Merty's picture

Anyone have experience with using treated foundation SIP's? How do they hold up in the long run? Are they strong enough for a full height basement surrounded by clay? Any tricks to installing them correctly?

Never built with SIP's but they seem pretty smart. (And who would have believed... the sales brochures didn't have a single bad thing to say about them!)

Pretty new at all this stuff.

(post #73753, reply #1 of 23)

Greetings Merty,

As a first time poster Welcome to Breaktime.

This post, in response to your question, will bump the thread through the 'recent discussion' listing again.

Perhaps it will catch someone's attention that can help you with advice.


 A bird does not sing because it has an answer. A bird sings because it has a song. 


(post #73753, reply #2 of 23)



A Pragmatic Classical Liberal, aka Libertarian.

I'm always right!
Except when I'm not.

(post #73753, reply #3 of 23)

I have seen wood foundation literature, but never with SIPs.  I have never seen SIPs with Ply faces, only OSB.  And I have never seen PT OSB.

I think strength is as much of an issue with clay as you'll have with the long term moisture contact.  They (PWFs) do best and last longest (which compared to masonry is not that long) in areas with well draining soils

What is the attraction of the wood foundation for you?

Edit - just re-read my post and it comes off as super-anti-PWF - -that is not the case, I am indifferent to them for the right location, but I prefer a masonry solution for my house.  If every faced with a challenge where I could not use masonry, I'd consider treated pole piers and an insulated floor before I'd go to PWF.  I figure if I can't get crete or block, I probably have other site and material access issues to contend with.
Adventures in Home Building
An online journal covering the preparation and construction of our new home.

Edited 9/15/2006 7:05 am by jhausch

(post #73753, reply #5 of 23)

Thanks for your thoughts.

The attraction is being able to errect the foundation without a specialized sub, having walls that are already well insulated and ready for d-wall, and having walls with the electrical chase built in. Cost of DYI vs. a foundation sub may fall just slightly on side of the SIP's.

Seems like it must be someone what proven since most of the SIP suppliers offer foundation panels. I haven't been able to find anyone who has used then that is either raving about them (other than the supplier) or less than enthused.

(post #73753, reply #6 of 23)

We are just finishing a Sip house with a sip panel wood basement.
Contact Extreme Panel out of Cottonwood MN
They can answer all your questions

(post #73753, reply #7 of 23)

We'll, I'll be dipped - I've never seen the basement panels before. 

Any special site prep or other conditions?  What sort of longevity is expected?
Adventures in Home Building
An online journal covering the preparation and construction of our new home.

(post #73753, reply #10 of 23)

Far as I can tell, just put down the footings and go. Depending on the existing soil/fill, you may have to use some gravel in the backfill (or at least that's what one of the handy pamphlets said). I'm guessing there may be some special designing when you have a walk out and have to step down the footings to stay below frostline.

(post #73753, reply #15 of 23)

They are just like a normal wood fondation only insulated and stronger.
Drainage is very important. We installed two layers of 6 mil plastic on the outside wall,drain tile and gravel. has more information.

(post #73753, reply #9 of 23)

I've gotten much of my initial info from those folks. So far I'm impressed them and even more so with Exercept out of SD. Did you do a cost comparison between the SIP's and ICF's? The whole idea of skipping the hastle of bringing the cement truck in to fill the ICF's and getting right to putting up walls is attractive-- but at what cost?

Good to hear from someone who has gone this route.

(post #73753, reply #16 of 23)

We thought about ICF's at first but dropped the idea after doing more research. The #1 Item on our list was low energy usage. We felt the Sips were better at this then the ICF's. Plus cement cost was very high.
$100/yd and we would need a pumper truck.
If you are interested your house can be seen at
look at the journal called candlepower.

(post #73753, reply #17 of 23)

Took a look at your project. That should be a wonderful house. I'll have to take a closer look at the website. If the D-wall is done and paint is on the way, occupancy must be awful close now. Good luck.

(post #73753, reply #8 of 23)


  Have you looked at ICF's?

  They are very do-it-yourself frendly. I started it and  had two courses in place  and my back* had me laid up.      My sister-in-law finished doing them for me and completed the whole basement in a day. Her previous experiance had been either painting or wall papering..

   * the result of a long car ride with poor seats, not anything to do with working with the ICF's

  I bought mine from my cement supplier.  He also lent me the bracing and scaffolding which he charged a slight rental fee for..

     He also arranged for a pump truck since their cement truck couldn't get access to my site.  While I was wore out after an hour of wrestling with the 4 inch hose it wasn't very difficult at all to pump the concrete in..that's about how long it took me to do..

  I had my oldest daughter (age 16) down on the forms running a sawzall without a blade as my vibrator and watching the forms to ensure there were no blow outs.  She thought it was silly untill I explained what she was doing and how important it was.. Then she got all serious and really took pride in it.  Afterwards as I installed the J bolts and leveled off the top She was just bubbling with excitement.  To this day she still fondly remembers doing it and her excitement at helping daddy. We started pumping at 8:30 and finished everything by about 10:30.

  Had a leasurly lunch and put water proofing on the forms in the afternoon.


  How to get waterproofing out of your hair..

      Use WD40..







(post #73753, reply #11 of 23)

No I haven't looked very seriously, being a timid little high school teacher by day, pretend contractor by night; I've shied away from being the one that handles the cement. You do make the whole prospect pretty intriguing.

By the bye, can you get WD40 as a gel additive?

(post #73753, reply #13 of 23)


 It's like working with leggos. and just about as hard.. The only thing at all difficult was wrestling with the 4 inch cement hose. When I did that I was 53  (grossly overweight {265, 5'9"}   having a sedentary job for the past 850 years,  (er, it only seems like it) 

  If I were to do it today I'd ask some young kids to help.  It's not difficult, about as complex as pouring pancake batter,, once you have the forms filled to the top you stop..

 Well to ensure that you don't have a blow out have the pump operator pump slowly and don't pour more than a course or two before moving. That allows it to settle and gives the vibrator a chance to ease out any air pockets..  You are walking along the scaffolding which is part of the brace system and about as complex to set up as a basic Tinker Toy..

 I used a bit of extra boards to ensure that I wouldn't have a blowout but they were later used elsewhere so I didn't waste them..

  Once the ICF's are up it's easy to sheetrock  Every few inches they have a strip of nylon which your sheetrock screws bite into and poof! The sheetrock is up.. No hitting a stud every 16 inches, just mark out where those strips are (I used chualk on the floor)  and you can sheetrock it faster than running from a stripped skunk..

  To make things easy Plan on how your phone, water, and electricty is going to enter the house.. If it's thru the basement walls use a bit of PVC pipe to provide the path before you pour the concrete.. it's real easy to drill thru foam and much harder to dill thru concrete..  (although it can be done if you use the equipment available at rental centers)..

 Once out of the ground please use the SIP's!

     I did and love them!  Ask and I'll give you lots of hints and details..

  Oh,  by the way!

       The first and thus far only house I've ever built is this one, and the only time I took wood shop I flunked it..




(post #73753, reply #19 of 23)

You bring up an interesting point...why isn't there PT OSB?

Justin Fink - FHB Editorial

Your Friendly Neighborhood Moderator

Justin Fink - FHB Editorial

(post #73753, reply #20 of 23)

My guess (an un-educated one at that) is if you make a sheet of OSB with waterproof glue/epoxy (something like advantech, for example), that it would not "take up" much treatment in the autoclave (or whatever it is they use).

You'd probably have to start with treated chips, then put them through an advantech like process.  Then, with all the wet treatment on the chips, no telling how well it would all bond.  It would be a question to ask an OSB mfg, though.

Might be interesting to soak a sheet of advantech in some treatment material and bury it anyways - to see how it would do.  I've read here that some folks have done long term testing of advantech sitting in a bucket of water - while "green and funky" the advantech has still not swollen or delaminated.
Adventures in Home Building
An online journal covering the preparation and construction of our new home.

(post #73753, reply #4 of 23)


 Interesting concept.. (I seem to be the loacl SIP advocate)  However I choose to use ICF's which are well proven technology,   quick to erect,  and not an issue with inspectors..

  While not quite as energy efficent as a SIP the strength and durability of the product is what made my selection of ICF's for me..  Once out of the foundation I went with the SIP's

 Both SIP's and ICF's  offered  solid insulation values compared to say poured walls with additional foam insulation or black walls with the same..


(post #73753, reply #12 of 23)

Hey Merty,

I am a SIP and PWF proponent. As a rule I am in favor of both. My last home was on a PWF and my current one is built out of SIP's.

I am however reluctant to put any treated wood foundation in soils that are anything but free draining. The proper site conditions are very important.

As a side note, what size of SIP do you intend to work with? I prefer jumbos, the design options they offer, and the fewer thermal breaks in the insulation you are buying.

Good luck,


(post #73753, reply #14 of 23)


 I used those big panels on my house too! but I have easy access to telehandlers (those big construction forklifts)  if I had to wrestle with SIP's by myself without a forklift I'd be much more inclined to use smaller panels

(post #73753, reply #18 of 23)

Hey Frenchy,

We requested that the pannels be "reasonable" sized. Most were in the 8x12 or 8x14 size.
One was 8x20 and it was too big to handle comfortably by hand. But we had to do it any way. The rest were easy with four guys and could be done by three.

I like having fewer splines.


(post #73753, reply #21 of 23)


 An 8x20 panel? Yeh, I guess three really strong and well corordinated guys could handle it.. I'm pretty old (the girls are well,... girly)  and have had sedentary jobs all of my life.. I'd rather screw a strap on it and handle it with a forklift. 

 The appeal of fewer splines is nice, however since I have 10 foot ceilings there were going to be splines someplace.


(post #73753, reply #22 of 23)

Wow, this is pretty intriguing. I've known about SIP panels since the early 1980's, and learned of their application beyond wall/roof (e.g. flooring), but I had never imagined a SIP panel being used for a foundation. Something about putting wood into the ground seems illogical. :)

I'll have to keep this idea and PWP in mind. As someone else mentioned, concrete can be an expensive option to consider.

SIP Wood Foundations (post #73753, reply #23 of 23)

I built my home, Garage and shop on a SIP foundation, the House was built in 1993.

I have excavated to the treated footers to inspect the foundation recently. The wood looked exactly like it had just been placed yesterday. The SIPs bear on a 2x10 plate which rests on 12" of gravel. We are in a flood plain. the lower level which is mostly 4' to 7' below grade stayys very warm and comfortable, in fact i have turned off all but one of the heat runs to the lower level years ago and it stays very comfortable and the humidity is very low (~40%) assisted by a HRV. The SIP walls are 8" thick nominal with 2x8 splines 4'OC. I have had no problems what so ever with the system and would not hesitate to use it again.

Frank Baker