|
You are not authorized to post a reply.
|
 Prev Next
|
| Author |
Messages |
|
mlennox
Registered Users
New Member
Posts:54
 |
| 02/05/2009 8:26 AM |
|
Hello, I am designing a
custom home that will start construction likely in May. My designer/builder has done many energy-efficient homes in the past using "standard" techniques (poured foundation, stick framing) with beefed up insulation and/or double-walls, etc. For this home we are also considering ICF and/or SIPs.
We are still waiting to hear back about ICF and SIPs pricing, but he has priced out in detail the various stick-frame wall techniques that he has previously done. I would be interested in getting some feedback from people in this forum about the pros/cons of the various wall systems he has specified, as well as how people feel they would compare against ICF and/or SIPs.
It's probably worth mentioning this home is being built in Easter Ontario, Canada (very cold dry Winter, hot humid summer) and we are very likely going to use a DX GeoThermal system with radiant in-floor hydronic heating.
2x6 Wall (R20)
2x6 plates
2x6 studs
OSB sheathing
2x10 lintel
R20 insulation
Vapour barrier
Price per LF $15.44
Price per R per LF $0.77
Double Wall 2x5 Plus 2x3 (R44)
2x4 plates
2x4 studs
2x3 plates
2x3 studs
OSB sheathing
OSB bracing & window frame
2x10 lintel
R20 insulation
R12 insulation (2 layers)
Vapour barrier
Price per LF $24.46
Price per R per LF $0.56
2x6 Wall With 2x3 Interior Strap (R32)
2x6 plates
2x6 studs
OSB sheathing
2x10 lintel
2x3 strapping
R20 insulation
R12 insulation
Vapour barrier
Price per LF $19.96
Price per R per LF $0.62
2x6 Wall With 2 Inch XPS (R30)
2x6 plates
2x6 studs
OSB sheathing
2x10 lintel
R20 insulation
Vapour barrier
R10 XPS foam
Price per LF $28.28
Price per R per LF $0.94
|
|
|
|
|
|
|
jimmy48
New Member
Posts:0
|
| 02/05/2009 11:37 AM |
|
i JUST BUILT A NEW HOME IN WATERLOO ONT LAST SUMMER . i DID 2X6 @ 24 0C WALLS WITH METAL BRACING INSULBOARD ON EXTERIOR 2 INCHES CLOSED CELL FOAM INTERIOR AND R 14 BATT GAVE ME R32 IN MY WALLS IN BASEMENT IS R28 1.5 INCH FOAM SPRAYED AGAINST THE WALL WITH A R 20 BATT
CEILINGS R50 IN FLOOR HYDRONIC HEAT ON ALL LEVELS WITH NG MOD/CON BOILER I PRICED ICF FIRST BUT IT WAS GOING TO COST ME $ 40k MORE THEN THE WAY I WENT WITH. i SEEN NO POSSIBLE PAY BACK ON ENERGY SAVINGS FROM THE ICF EVERYTHING IVE READ SAYS THERE IS VERY MINIMAL OR NO BENIFET AT ALL FROM THE THERMAL MASS FOR OUR CLIMATE I FIRED MY HEAT UP ON OCT 28 MY TOTAL COST TO HEAT THE HOUSE FRON OCT28 TO JAN 20 WAS $ 435.00 . VERY HAPPY SO FAR I THINK ILL BE AROUND 1000- 1200 A YR IN HEATING COSTS |
|
|
|
|
tb1472000
Registered Users
New Member
Posts:61
|
| 02/05/2009 12:13 PM |
|
I'm confused. The price per LF of wall, is that for an 8' tall wall with studs, sheathing, insulation, etc? If so, what is the insulation cost number or do I have to add the two together? |
|
|
|
|
mlennox
Registered Users
New Member
Posts:54
|
| 02/05/2009 12:30 PM |
|
Posted By tb1472000 on 02/05/2009 12:13 PM I'm confused. The price per LF of wall, is that for an 8' tall wall with studs, sheathing, insulation, etc? If so, what is the insulation cost number or do I have to add the two together?
Sorry, I should have been more specific. The cost-per-LF shown is the combined total for the framing and insulation. The calculations were all done using a 14 foot wall, 9 feet high with one standard sized window.
I actually have the cost-per-LF figure for framing and insulation separate, but I omitted this from my original posting.
The second figure is the cost-per-R value per linear foot (also based on total cost of framing and insulation).
Lastly, these are only material costs, no labor.
|
|
|
|
|
mlennox
Registered Users
New Member
Posts:54
|
| 02/05/2009 12:32 PM |
|
Posted By jimmy48 on 02/05/2009 11:37 AM
IN FLOOR HYDRONIC HEAT ON ALL LEVELS WITH NG MOD/CON BOILER
I'm curious about your hydronic system, can you give me an idea of how much you ended up paying per sqft living space, and what type of installation you did (gypcrete floors, in slab sensors, etc., etc.). I'm getting some pretty wild cost estimates for this portion of the home and I'm trying to figure out if it's reasonable.
|
|
|
|
|
mlennox
Registered Users
New Member
Posts:54
|
| 02/05/2009 12:41 PM |
|
Posted By jimmy48 on 02/05/2009 11:37 AM
IN FLOOR HYDRONIC HEAT ON ALL LEVELS WITH NG MOD/CON BOILER
Also, can you give me an idea how much ducting you had to put in and how you are cooling the home in the summer? Thanks again.
|
|
|
|
|
jimmy48
New Member
Posts:0
|
| 02/05/2009 6:05 PM |
|
| MLENNOX i ran ducting for my hrv which you will want to put in your home if you insulate very well you should be exchanging the air because your house should be very tight most of my duct sizes were 4 and 6 inch to the rooms my house is cooled by ac 14 seer goodman My heating system is triangle tube boiler prestige model 5 inch basement slab 4 inch garage slab tubes were wire tied to 6x6x6 wire mesh 1.5 inch gypcret floor on main and second floor My tubes were stapled to main and second floor over 3/4 t/g osb engineerd floor joists both floors every room has its own therm , and floor sensors in every room outdoor sensor teckmar controls dhw connected to the boiler as well i will look back at my costs the labour was all done by myself and a friend who is a plumber and does many hydronic systems so i saved there quite a bit. You definatley want a heat load done for your house so you can get the proper design and layout for what you really need i spent $ 500.00 to have one done and it was well woth it |
|
|
|
|
jimmy48
New Member
Posts:0
|
| 02/05/2009 6:13 PM |
|
m lennox what size/style of home are you planning
|
|
|
|
|
mlennox
Registered Users
New Member
Posts:54
|
| 02/06/2009 10:04 AM |
|
Posted By jimmy48 on 02/05/2009 6:13 PM
m lennox what size/style of home are you planning
Roughly 1850sqft living space on 2 floors, plus finished basement space and future finished attic space.
|
|
|
|
|
aardvarcus
Registered Users
Basic Member
Posts:176
|
| 02/06/2009 11:40 AM |
|
You really can't ignore labor costs unless you are going to do it yourself. The labor costs of a single stud vs double stud will be very different. That being said, double stud will still be your best R's for the buck. I like the look of your double wall, but I wouldn't put in a 2*3 stud. Just go ahead and use a 2*4 stud, it only costs a touch more and will typically be stronger and straighter, cutting down on labor of hassling with crooked material. If you want to make your wall stronger, double diaphragm the outer of the two walls. That means put osb on the inside of the wall too after you insulate it. That will turn your entire wall into one giant box beam, and keep the studs from twisting or pulling away from the plate. It sounds silly, but makes your wall immensely stronger, and it eliminates the need for a beefed up header.
What kind of insulation are you putting in the wall? If you go double stud, what will you fill in between the studs with? What is your exterior siding? |
|
|
|
|
Birdman
Registered Users
New Member
Posts:40
|
| 02/06/2009 1:32 PM |
|
You're essentially asking the same question i've been asking myself and drawing some of the same conclusions. I'm contemplating a house in a different climate, an island with very high wind loads (120 mph) fairly cold winters (record low -7F average January about 25F) and mild but very humid summers.
I liked ICF's as being wind, water and storm resistant and labor efficient (island labor is VERY expensive). I also liked being able to frame the 1st and 2nd floors with steel joists and concrete (like you I plan on hydronic radiant heat without A/C) On the downside is the very high cost (again island concrete is $200/CY)
I looked at SIP's but I cannot get past the fact that once moisture (which is HUGE in my climate) gets to them there's very little substance there to resist it's effects. I know folks believe they can design a "perfect" system to keep the water out but everything fails eventually and when it does it seems the structure would be in peril very soon after the weather barrier fails (and maybe before anyone knows the barrier has failed). Human nature what it is, does anyone know a case where someone replaced a roof because it was old but not yet leaking? Put on a "25 year" roof and mark your calendar, then 25 years later rip it off even though it's still tight - I don't think so.
So that brings me to some of the variations you propose. I like the approach of Joe Lstiburek of Building Science - very pragmatic and science based. ( buildingscience.com ) He focuses not only on thermal performance but also moisture management and prevention of infiltration. He focuses on several flaws in stick construction - Overuse of framing members displacing insulation, thermal bridging of studs, bringing dew point inside the sheathing and infiltration. His approach is to stick build but only sheath with OSB or Ply at corners or where structurally needed and sheath the entire exterior with board insulation (polyiso or xps). This kills the thermal bridges and keeps the dew point outside the sheathing. He solves the infiltration issue by sealing the interior side of the sheathing with an inch of spray foam then provides additional R with cheaper blown cellulose. He advocates for "advanced framing" 2x6 at 24" oc with reduced headers, single plates, two stud corners etc.
Except for carrying a concrete slab second floor this seems to do what I need it to do. energy and material efficient, durable, reasonable cost, flexible to repair/retrofit, relatively easy for trades to understand w/o a big learning curve.
I will be trying to work out a SF or LF cost for this as you have done (are you dollars CDN?)
Meanwhile, I'd love to hear the discussion, pros, cons and otherwise on the above.....
|
|
|
|
|
The Sipper
Registered Users
Basic Member
Posts:133
|
| 02/06/2009 7:08 PM |
|
So, I just finished a post, on this forum "Green Building, Residential....." the thread being "Strawbale vs ICF Walls" I was just expressing my opinions in regard to the "double stud wall" approach so maybe if anyone is interested in seeing where I'm coming from on this construction method, they will take the time to check out my comments. Frankly, I'm certain that these elaborate framing methods will not equal SIPs or ICFs, in regard to most "Green Building" Standards. I also think that in order to equal the energy efficiency of either of these systems, the quantities of materials, along with the excessive labor factors, would result in even higher costs, particularly when compared to SIPs, and would not have the inherent strength of ICFs. (I think that most of the "pros" on this site will agree that ICFs are more expensive than SIPs, right?)
Maybe some of you other SIP and ICF advocates will chime in with some different perspectives on this subject.
In the meantime, Birdman, you're certainly taking a thorough approach to the selection of a building system, or method, for your project, however, I have a few questions, and comments, in regard to some of these concepts.
1. ICFs are likely the ideal wall system under the conditions that you've described, however, the $ 200 c/y for concrete does make this option a bit pricey,
though, it is what you might call a "forever solution", probably won't have to be concerned with many repairs.
2. SIPs, if installed properly, will likely meet your requirements, will cost less than ICFs, and probably not much more, if anymore, than good quality framed
construction.
3. Joe L.'s "Building Science" approach is probably based on some pretty sound principles, however:
a. Will this "advance framing" technique, with studs at 24" OC, single top plates, and OSB or plywood sheathing only at corners, etc., be engineered for
120MPH winds?
b. If "everything fails eventually" (Depends on what the definition of "eventually" is) then why won't you have to consider the possibility that the OSB
or plywood corner bracing used in this "advanced framing method" would be subject to failure when the weather barrier that is protecting it fails?
And, if that happened, wouldn't the whole structure become unstable". With SIPs you have continuous sheathing on both sides, and there are
structural members that support the roof structure, some buried within the SIP walls. My point here is that if you can "perfectly protect" 4' of s
sheathing at each corner, you can likely protect the entire exterior. Also, it is a fallacy that OSB will disintegrate immediately when introduced to
moisture, and there is much anecdotal evidence to backup this statement. There have been literally thousands of OSB SIP homes built along our
coastal areas, in the mountains, deserts, and in virtually every other area of our country, and around the world, and I've not seen one written article
or internet post, regarding structural wall failures with properly installed SIPs (I only did a quick Yahoo search, and only came up with the old "Alaska
Fiasco" SIP roof failure story,.........a result of improper installation. However, I'm sure that someone will be able to dig up some, with a more in
depth search, though, any such instances will still likely be the result of improper installation of the SIPs and/or the moisture barriers, or a result of a
catastrophic occurance that exceeded the design limitations for a particular structure in a particular area).........(Its about time for CK to check in
with his steel skin SIPs, certainly moisture resistant, but maybe not as readily available in all parts of the country, along with some other issues that
may make OSB SIPs a better choice in many cases)......That should do it for now.
Good luck with your search for the "best" building system for your project! (That's what this is all about isn't it?)
|
|
|
|
|
The Sipper
Registered Users
Basic Member
Posts:133
|
| 02/06/2009 7:18 PM |
|
| I apologize for the way my last post was published, "spread out" that is. This at least the second time that's happened, makes the post appear longer than it is. However, I'm not sure how to correct this problem as it doesn't happen every time. |
|
|
|
|
Alton
Registered Users
Advanced Member
Posts:662
|
| 02/06/2009 7:32 PM |
|
The Sipper,
You might want to ask Jamie, the Administrator, what causes the lines to spread out. She has been very good about answering my questions dealing with posting. Did you use the forum editor or did you use another editor and cut and pasted it to this forum? It appears that the line lenght is so long that it doubled back. |
|
Alton C. Keown
Residential Designer and Construction Technology Consultant
Auburn, Alabama
E-mail: alton at auburn dot edu |
|
|
Birdman
Registered Users
New Member
Posts:40
|
| 02/07/2009 11:03 AM |
|
Sipper,
Thanks for the thoughtful reply - i particularly like this site because of the high level of discourse here. Your points are well taken and please understand I'm not "sold" yet on any one method - all have pluses and minuses.
That said, I was pretty much originally planning on ICF's for my house but am finding them cost prohibitive (especially after looking at my shrinking portfolio!) I was annoyed that some ICF manufacturers continue to tout the "R50 equivalent" due to thermal mass effect - but I'm over it. ICF's are just a way of building a nice tight R22 wall - which is fine. As you say it is the ultimate construction to resist 120 mph wind loads - and concrete and xps are about as moisture resistant as materials get.
Your points about properly protecting SIP's are certainly true - with proper detailing, flashing, vapor/air barriers and drainage planes I'm sure SIP's could provide a durable building. (by the way Joe L. has a book out on SIP's so he's not opposed, but I haven't seen it) The only thing you said that I might quibble with is the notion of water getting to OSB sheathing is comparable to it getting to SIP's. Worst case, it's one thing to tear off some siding and replace some sheathing - quite another to have to replace a SIP panel (I'm not looking at fastening these to a frame). The foam core of the panel might prevent water from being evident, particularly in a roof, for quite a while, meanwhile the skin of the panel could be lost. With conventional construction, when replacing a roof it's certainly common to find some damaged sheathing and a simple matter to replace it - replacing a SIP roof or wall panel sounds like a nightmare to me.
The "advanced framing technique" (which I guess is sort of an official name for a whole method) is fairly sophisticated and requires a higher understanding of the engineering of framing, but in a nut shell it's about removing sticks that aren't doing anything anyway. For example, having a king cripple and jack stud at a window opening in a nonbearing wall really is wasted lumber and given that insulation insulates better than lumber it creates a thermal bridge. The thought is that about 15% of the area of framing in the wall can be replaced with insulation - a fairly significant improvement in energy load over the life of a building. It's worth a look.
Obviously in my case I need to engineer my project for massive wind loads and I tend to be conservative so I would add redundant bracing as a matter of course.
Thanks again,
|
|
|
|
|
PanelCrafters
Registered Users
Veteran Member
Posts:1408
|
| 02/07/2009 7:32 PM |
|
Posted By Birdman on 02/07/2009 11:03 AM
...That said, I was pretty much originally planning on ICF's for my house but am finding them cost prohibitive (especially after looking at my shrinking portfolio!) I was annoyed that some ICF manufacturers continue to tout the "R50 equivalent" due to thermal mass effect - but I'm over it. ICF's are just a way of building a nice tight R22 wall - which is fine.
Yup, if money was no object, I would use ICF's on my next cabin/cottage/house(whatever it ends up being) for the walls. But, I would add extra insulation(to the inside) to get the wall up to Super Insulating(R-38 or greater). It tends to get cold in Colorado ;). But, as you noted, most people have lost a lot of their loot, and cost is an issue. In Colorado, you are probably looking at a 33-50% premium for ICF walls.
The way things are going, I think that it's going to be tough for either SIP's or ICF's to gain market share in this economy. However, either(or both!) technology is the only way to build!
|
|
....jc
If you're not building with OSB SIPS(or ICF's), why are you building? |
|
|
SLC
Registered Users
New Member
Posts:8
|
| 02/16/2009 7:52 AM |
|
Hi mlennox,
Keep us informed this is very interesting especially for me since we will also be building in Eastern Ontario in either late fall 09 or early spring 10. Just a stupid question does the second wall have to be on top of the foundation i.e. does your fondation have to be wider to accomodate? or does the interior wall just go on top of the floor.
Any information greatly appreciated.
sly |
|
|
|
|
mlennox
Registered Users
New Member
Posts:54
|
| 02/16/2009 9:46 AM |
|
Posted By SLC on 02/16/2009 7:52 AM Hi mlennox,
Keep us informed this is very interesting especially for me since we will also be building in Eastern Ontario in either late fall 09 or early spring 10. Just a stupid question does the second wall have to be on top of the foundation i.e. does your fondation have to be wider to accomodate? or does the interior wall just go on top of the floor.
Any information greatly appreciated.
sly
To be honest I'm not quite sure, though it's quite likely that we will be doing at least an ICF basement which means a 12 inch wall. I don't think any of the wall configurations we are considering would be more than 12 inches total and so would fit nicely on top of the foundation wall.
However after receiving a few ICF quotes, we are now leaning quite heavily towards a whole-house ICF configuration, though I'm still trying to wade through all the mis-information about whether or not ICF makes sense in northern climates with extreme cold Winter and extreme hot summer.
|
|
|
|
|
Jamie
Forum Moderators
Veteran Member
Posts:2448
|
| 02/16/2009 10:10 AM |
|
Posted By The Sipper on 02/06/2009 7:18 PM
I apologize for the way my last post was published, "spread out" that is. This at least the second time that's happened, makes the post appear longer than it is. However, I'm not sure how to correct this problem as it doesn't happen every time.
Those are line breaks. You probably wrote it in note pad with “wordwrap on” and forgot there was line breaks. You can just go back and edit it by pressing backspace where the lines abruptly end.
Thanks,
Jamie |
|
|
|
|
glenfotre
Registered Users
New Member
Posts:39
|
| 02/16/2009 10:13 AM |
|
| It's my understanding, that if you are doing upper walls in ICF, that they must be directly over the lower ICF walls. A friend here had his daylight basement in ICF, but since the main floor wall was about 12' in to allow for a porch, he had to stick build that wall. YMMV! |
|
|
|
|
|
| You are not authorized to post a reply. |
|
|
|
ActiveForums 3.6
|
Professionals Serving
Your Location:
|