lzerarc
Basic Member
Posts:423
 |
| 12 Aug 2010 12:06 AM |
|
As we continue to bounce around construction methods, I have yet another comparison thread involving initial costs of materials. Here are 2 options I am weighing in on: SIPs vs stick framing but efficient. Some info about the build: roughly 1700 sqft, single story with full basement (most likely ICF). Prairie style house with 9' ceilings and also a large 14' main foyer/living/dining area. Not crazy about of windows, only about 9, plus then about 4 clear-story ones. All rectangular in shape. 10 total corners, 188 lin. feet of exterior wall (plus garage, however that would be stick framed). I do have construction experience, and would be building it all myself. No contractor involved, so savings on labor is not an issue. I am looking for raw, pure materials costs. I have been reading around a lot, and it looks like for materials cost SIPS starts out at around $5 sqft for a 6" panel. IS an 8" panel worth it for single story construction? However what I do not know yet is how cut outs, lintels, and fabrication of the panels will affect that price, on average. Do anyone have a ballpark of what their package ended up being? Is $7 sqft a safe number? Obviously I need to send my rough plans off to some SIPs makers, but in the mean time I would like to know what to expect. On the flip side, going 2x6 framing with 1/2" osb, 1.5" XPS on the exterior, spray foam on the interior, or possibly an R-19 batt instead. This system will cost around $4-6sqft , depending on the spray foam. So between the 2 systems, obviously the SIPs will save a ton of time, which is a huge interest to me since it will be my vacation time used to build  SO does anyone have any insight on SIPs and approximately where they are coming in at price-wise for materials? |
|
|
|
|
|
|
trigem1
Basic Member
Posts:123
|
| 15 Aug 2010 04:33 PM |
|
I’ve heard several contractors state that they can stick build “just as good as SIP’s”. Baloney. OK, lets do a couple of quick comparisons. A 6-1/2 inch SIP wall has an average whole wall R-value of 24. A 6 inch stick built wall has an average R-value of about 14 because of the studs, with an R-value of about 4 and R-19 batt insulation makes an average of R-14. To match the R value of a SIP wall, you would need to frame with 2 X 12’s with R-30 fiberglass insulation. The other part of the equation is having an air tight envelope to stop cold air coming in and your expensively warmed air from escaping your home. To get close, you would have to caulk all the seams of the sheathing where they come together and at the top and bottom plate. Have you ever noticed how on a cold and windy day how cold air comes out of the wall outlets? That’s because the cold air is inside your walls. A SIP wall, if installed properly, has very few thermal breaks and is sealed side to side and top and bottom, usually with a triple redundancy. In other words, it’s sealed on the outside and the inside. About now you’re thinking, hey, what about the spray-in foam? Spray-in foam is a much better insulation material than fiberglass and does a better job of sealing up leaks. That’s why it works so well around doors and windows and in SIP’s. Drawback of spray-in foam? It’ll run you around $3.00 a square foot to have it installed. It’s always difficult to accurately ballpark guess the square foot price of SIP’s because of so many variables. Like local tax rates, local wind loads, local snow loads, local codes (minimum R-values), shipping charges, how thick will the wall and roof panels be, how many trucks, would you like an on-sight trainer? I understand the frustration of trying to get a handle on prices, and that’s why many suppliers offer free estimates. Bottom line, if you want a very energy efficient, strong, fast to assemble home, go with a good brand name, reputable SIP.
Steve
GrandCountySIPs.com
|
|
| Steve Etten |
|
|
Alton
Veteran Member
Posts:2164
|
| 15 Aug 2010 05:04 PM |
|
Steve,
I think you meant to say that a SIP wall has very few thermal paths - not thermal breaks. Right? |
|
Residential Designer &
Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period .
334 826-3979 |
|
|
trigem1
Basic Member
Posts:123
|
| 15 Aug 2010 06:33 PM |
|
Right
|
|
| Steve Etten |
|
|
jonr
Senior Member
Posts:5341
|
| 15 Aug 2010 09:54 PM |
|
You could compare to 2x6 with cellulose and 2" of taped XPS foam. You can skip the OSB by using a couple of techniques.
|
|
|
|
|
cmkavala
Veteran Member
Posts:4327
|
| 16 Aug 2010 08:37 AM |
|
SIPs are far superior in structural and thermal performance to any conventional method |
|
| Chris Kavala<br>[email protected]<br>1-877-321-SIPS<br /> |
|
|
Jere
Basic Member
Posts:106
|
| 16 Aug 2010 09:56 AM |
|
Posted By lzerarc on 12 Aug 2010 12:06 AM
On the flip side, going 2x6 framing with 1/2" osb, 1.5" XPS on the exterior, spray foam on the interior, or possibly an R-19 batt instead. This system will cost around $4-6sqft , depending on the spray foam.
If you use 2x6, you can go 24" o.c., reducing the number of studs required, saving money on material and time... this also gives a higher overall R-value since there is more insulation, less studs. Using 1-1/2" xps on the exterior of framing from foundation to roof taping/sealing all seams, 1" of closed cell spray foam to air seal, then fill balance of cavity with spray in cellulose, you will get a very well insulated and air tight home... resulting in the best bang for the buck. The spray in cellulose also adds some thermal mass. Also spray foam rim joists, and spray foam 1" in attic w/ blown in cellulose on top... or spray foam roof deck. Check with your building department about ICF basements if you need to drywall over the foam before you can get your certificate of occupancy. This was the case for me in Michigan when I built my home. I didn't want my property taxes to based on the additional square footage for the finished basement, plus I didn't have the additional money in my construction loan to cover the ICF cost increase plus drywall material & labor... I used Superior Walls precast insulated concrete for my foundation and have been very happy. |
|
I built my home with the help of Pierson-Gibbs Homes, "The Hands on House". They build the shell, you finish it.
www.p-ghomes.com |
|
|
lzerarc
Basic Member
Posts:423
|
| 16 Aug 2010 11:54 AM |
|
I have been talking with some SIPs suppliers in the area. One maker uses solid core polyurethane and also offers treated basement panels with a 75 year warranty. The 4" panel (they claim to get an r-26.9 due to the foam type) runs $4.89 sqft total package. The 6" (r-42.3) runs $5.22 sqft. Price of the construction method I mentioned would be around $4 with exterior foam and batt, but higher with spray foam, about $5.50-6. However the time savings (DIY) would be huge with SIPs, and time is a big factor here.
It looks like SIPs are the way to go so far. Any thoughts on the different foam types? |
|
|
|
|
Dana1
Senior Member
Posts:6991
|
| 16 Aug 2010 06:01 PM |
|
Posted By lzerarc on 16 Aug 2010 11:54 AM
I have been talking with some SIPs suppliers in the area. One maker uses solid core polyurethane and also offers treated basement panels with a 75 year warranty. The 4" panel (they claim to get an r-26.9 due to the foam type) runs $4.89 sqft total package. The 6" (r-42.3) runs $5.22 sqft. Price of the construction method I mentioned would be around $4 with exterior foam and batt, but higher with spray foam, about $5.50-6. However the time savings (DIY) would be huge with SIPs, and time is a big factor here.
It looks like SIPs are the way to go so far. Any thoughts on the different foam types?
High density polyurethane offers a considerable structural upgrade over medium density EPS. If you can boost your SIP's R value to R42 up from R27 for only an additional 33 cents per square foot you'd be crazy to pass that deal up! You can't buy an extra R15 in sprayed polyurethane for anything like that price! In many temperate climates (and even some cooler ones) R42 clear-wall values can be enough to pretty much skip the heating system if you size & place/rate the windows correctly, whereas R27 would require "real" mechanical systems for heating & cooling. IIRC the PassiveHouse they built in chilly Belfast Maine was done with 6" polyurethane SIPs and a heluva lot of design tweaks. See: http://www.gologichomes.com/blog/tag/passive-house/ |
|
|
|
|
GuyB
New Member
Posts:52
|
| 17 Aug 2010 06:51 AM |
|
Posted By lzerarc on 16 Aug 2010 11:54 AM
I have been talking with some SIPs suppliers in the area. One maker uses solid core polyurethane and also offers treated basement panels with a 75 year warranty. The 4" panel (they claim to get an r-26.9 due to the foam type) runs $4.89 sqft total package. The 6" (r-42.3) runs $5.22 sqft. Price of the construction method I mentioned would be around $4 with exterior foam and batt, but higher with spray foam, about $5.50-6. However the time savings (DIY) would be huge with SIPs, and time is a big factor here.
It looks like SIPs are the way to go so far. Any thoughts on the different foam types?
What state are you building in? Some things to chew on: Many jurisdictions will require engineering on a sip home regardless of a prescriptive method. So you need to factor in the cost and difficulty of finding an engineer well versed in sip construction. Depending on your design you may need to resolve your point loads to the foundation directly. With 2x6 construction, additional members are added sometimes 4 or 5 wide for sufficient capacity. In an exterior wall this will reduce your total r-value significantly. A point usually missed is that the effect is exactly the same in a SIP wall with 2x posts buried in the wall. An understanding of how many posts are required in relation to total wall area is an important consideration in determining which panel to use. Again an engineer with solid SIP experience may be able to spread the load using the properties of the panels themselves, but most will not. Generally speaking if you have high uplift, seismic or other loads that require heavy strapping. The cost of sips will rise much faster than the cost of 2x6 with an outside wrap of xps. Most of the increased cost will be labor. Spray foam doesn't work real well in these applications either. An experienced engineer may be able to model the panels as shear walls eliminating a great deal of strapping, but most will not. Finally consider your siding. Veneer brick or stone, shingles and clapboards install the same way regardless of 2x6 or sip construction. If you decide on a thin brick or lick and stick type of stone application. Then the attachment details need to be engineered and approved. Its not that the sip cannot support the weight. But when the lath needs to be screwed to an osb skin at zz centers as opposed to nailed to a 2x on yy centers suddenly we exit most peoples' comfort zone. |
|
|
|
|
lzerarc
Basic Member
Posts:423
|
| 17 Aug 2010 08:48 AM |
|
Good points. We are in Iowa, so our biggest contendor is the climate and some wind loading. Typically 90 mph is used, however I have designed safe room applications requiring 200 FEMA loads. Walls are 9' high around the exterior, single story, 6:12 pitch probably. Most likely doing trusses instead of SIPs for the roof for cost savings.
The 2 SIPs people I am currently talking to have in house engineers that will provide the stamp if required. They said usually it is at no extra cost, depending on the house design. He said our design was simple enough it shouldnt be an issue.
Being as SIPs are not that common around here yet, and our city/state basically requires a licenses to do anything anymore and not the homeowner, I assume they will want a seal having worked with them many times in the past. |
|
|
|
|
JeffD
Basic Member
Posts:282
|
| 17 Aug 2010 12:07 PM |
|
lzerarc,
Have you considered this product for your basement walls with SIPs on top?
http://www.superiorwalls.com/
|
|
| Metal SIP Building Designer<br>jeff@panelfusion(dot com) See us on Facebook |
|
|
wes
Advanced Member
Posts:810
|
| 17 Aug 2010 04:54 PM |
|
Izerarc,
Stick with the ICF basment, far superior to Superior Walls. (sorry Jeff) |
|
| Wes Shelby<br>Design Systems Group<br>Murray KY<br>[email protected] |
|
|
GuyB
New Member
Posts:52
|
| 18 Aug 2010 11:23 AM |
|
Superior makes a good product. How happy you are with the product will be heavily influenced by the installation crew. Unfortunately the crews I have dealt with have put Superior on the do not call list. I have heard of some outstanding installation crews in other regions. If your interested you really need to investigate your specific region.
Price wise its in the same ball park as ICF. From a timing perspective an entire Superior foundation can typically be erected in less than a day. But, you need to factor extra time for your excavator to put in crane pads to facilitate the installation. If you have a sloped lot or obstructions crane pads and access can add substantially to installation cost.
As an owner/builder you need to consider some of the finer points of Superior foundation installation. For instance you can't back fill at all until both the basement slab and the first floor deck are installed. This is true to some extent with conventional or ICF poured foundation as well. Typically with bracing or select fill or a ratio of unbalanced fill to wall length a poured wall can be back filled. Without back filling constructing the 1st floor deck is more difficult and time consuming. Which translates to more expensive.
|
|
|
|
|
lzerarc
Basic Member
Posts:423
|
| 19 Aug 2010 10:30 PM |
|
I have researched Superior walls and I really do not have an interest in using them. I got quote for ICF basement, installed, approximately 188 lin. feet, 8' tall (truss for floor would be bottom bearing, sit on top of walls), 8 corners for $23,700. This does not include the basement flatwork however.
My first SIPs quote came in at $22,000 for the package, $27,000 installed. This works out to be around $10.50/sqft. Seems fairly high. |
|
|
|
|
greentree
Advanced Member
Posts:587
|
| 22 Aug 2010 09:29 PM |
|
So if ICF is $126 LF why would you not go with poured wall and xps foam; cheaper and more R value? |
|
|
|
|
lzerarc
Basic Member
Posts:423
|
| 23 Aug 2010 10:22 AM |
|
Ultimately probably would. However to the price of the poured, I would also need to add the 2x to fur it out as well, and the time it takes to do that. ICF I am ready to sheetrock. However one option we have with poured is, we do not have to finish it completely to live in there like we would with ICF. Our code states you need to have the ICF foam covered in sheetrock before you can live there. If money becomes an issue, then the poured exposed walls would work until we finished it. |
|
|
|
|
Jere
Basic Member
Posts:106
|
| 25 Aug 2010 09:33 AM |
|
Posted By GuyB on 18 Aug 2010 11:23 AM
Superior makes a good product. How happy you are with the product will be heavily influenced by the installation crew. Unfortunately the crews I have dealt with have put Superior on the do not call list. I have heard of some outstanding installation crews in other regions. If your interested you really need to investigate your specific region.
Price wise its in the same ball park as ICF. From a timing perspective an entire Superior foundation can typically be erected in less than a day. But, you need to factor extra time for your excavator to put in crane pads to facilitate the installation. If you have a sloped lot or obstructions crane pads and access can add substantially to installation cost.
As an owner/builder you need to consider some of the finer points of Superior foundation installation. For instance you can't back fill at all until both the basement slab and the first floor deck are installed. This is true to some extent with conventional or ICF poured foundation as well. Typically with bracing or select fill or a ratio of unbalanced fill to wall length a poured wall can be back filled. Without back filling constructing the 1st floor deck is more difficult and time consuming. Which translates to more expensive.
Price wise for Superior Walls isn't even close to ICF. My entire Superior Walls foundation cost $12,764 installed, this was 8 years ago... this included 134' lineal for basement wall 9' deep, 96' lineal garage 4'-8" tall panels, 36' lineal porch 4' tall panels, brick ledge around the entire basement, garage, and front porch, (3) daylight window openings, and precast concrete lolly pads for the steel beam/columns. It was something like $65/lineal ft. for the 9' tall basement walls, and around $30/lineal ft. for the garage & porch panels.... even if the cost increased 20% over the past 8 years, it would still be a lot less than ICF... in a previous post, someone mentioned $126/lineal ft. Having the excavator put in a crane pad was no big deal... I needed crushed concrete base for my driveway anyway. the crane was positioned in my driveway right in front of the garage. |
|
I built my home with the help of Pierson-Gibbs Homes, "The Hands on House". They build the shell, you finish it.
www.p-ghomes.com |
|
|
Jmich
New Member
Posts:1
|
| 26 Aug 2010 12:41 AM |
|
Questions about the whole wall Rvalue difference ot SIPs and 2x6. What about a "Mooney" wall (2x4 studs with horizontal 2x2s) with spray foam or Batts and foam board the maerial costs should still be pretty low. This would take out most of the thermal bridging but would it help the whole wall R-value? |
|
|
|
|
jonr
Senior Member
Posts:5341
|
| 26 Aug 2010 10:03 AM |
|
Have you looked through all the information available at:
http://www.buildingscience.com/resources/high-r-value
All three of the top rated walls used studs and some foam. |
|
|
|
|