We need some design help and feedback...
Last Post 06 Dec 2009 11:41 PM by mapnerd. 11 Replies.
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karlitoUser is Offline
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20 Oct 2009 02:28 PM
My wife and I are trying to design and GC a simple 30x50 ranch w/basement house for an Iowa location.  We want to stay under 200K.  Our current thought process is:

 * Poured foundation
 * 2" EPS outside of foundation
 * EPS under slab
 * 5 1/2" EPS steel SIP walls
 * Steel truss hip roof, vented
 * Would like a standing seam metal roof but haven't looked into cost yet
 * ceiling drywall on hat channels under trusses
 * 3" CC SPF sprayed on top of ceiling drywall
 * Speedfloor or some other steel / concrete flooring system with radiant heat.  Thus, entire basement is somewhat like a saferoom... concrete on all sides.
 * Radiant heat in basement slab as well
 * House is 30x50 with a (steel stud) bearing wall dividing basement into halves, so floor joists have 15ft span.  I assume a bearing wall is more economical than a wide flange beam?

We are doing basement exterior insulation since we want a dry inside wall with thermal mass.  I'm not impressed with ICFs in this regard.  Also, with no exposed foam we can postpone finishing the basement.  We are doing all steel structural components since the below grade foam makes a termite highway.  We also want to use steel interior framing and liquid nail (I'm very concerned about anchor bolts hitting the radiant tubing).

The biggest problem at the moment is the 2" offset in our outside walls where the steel SIPs meet the foundation foam.  The wife is concerned about that being a wear surface, and it being ugly.  She suggested 2x4s to fur out the SIP wall and put the siding on that, but that seems to me an inefficient approach.  Tthe hardiplank requires 24" OC studs so it may not blow the budget compared to other things we are doing... Would that be a problem furring out siding that much?  Strength, installing windows and doors, etc?  Are there any other technologies we should seriously consider? 

The second problem is protecting the foundation foam.  Is real stucco that terribly expensive if you do it yourself?  We have heard horror stories (on this board) of freeze/thaw damaging masonry brick facades that went down to the footer.

We will also probably request a quote, for comparison purposes, on a simple gable SIP roof, if the ridge beam can span 40 or 50 feet.  We can also consider putting SIP ceiling panels under the trusses and putting only an inch or so of SPF on top.  If you read all that, thanks for reading!



energy_efficientUser is Offline
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21 Oct 2009 08:03 AM
Hello Karlito,

Don't wanted to discourage you but all the bells and whistles you want for $200k...on a 1500Sf w/full basement + heated floors, etc...
But what grabbed my attention is : "...The biggest problem at the moment is the 2" offset in our outside walls where the steel SIPs meet the foundation foam.."< ...and should I add also at where exterior wall and your roof meet....Check out Solarcrete system...the walls begin below frost line, so there are NO energy gap. Exterior walls are 1' thick. This system around 30+ years. PM if you need more info!.

Joe
energyefficienthouse.com


slenzenUser is Offline
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21 Oct 2009 04:48 PM
What is solarcrete's market area? How strong and durable are the plastic ties that hold the two slabs of concrete together?


energy_efficientUser is Offline
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21 Oct 2009 09:08 PM
Where you located?


Eric AndersonUser is Online
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21 Oct 2009 09:14 PM
Some quick things to consider. You have a very tight budget. My recommendations are in part based on that. It may be a lot cheaper to build where you live then where I live so keep that in mind. I think you might be trying to over think this thing. First, you need to get a handle on what your excavation, septic/sewer and driveway costs are. If you know that, then the house budget is everything else Generally speaking if you have a 4” slab in the basement on top of 2-3” of XPS That is plenty of thermal mass UNLESS you are trying for a fully solar heated house. This may tilt the equation in favor of ICF for the foundation (except ICF is not cheap). You might not have to cover the ICF foam in the basement. A lot of AHJ’s won’t care. I haven’t covered mine. For the first floor, I would use a triple LVL as the center carrying beam and probably 4 laly columns on footings to hold it up. I would do the floor with I-Joists 16” oc and then 7/8 advantec over that. I don’t think your budget is going to make sips work(but I admit I could be wrong). For walls I would use 2X6 stick frame OVE. On the exterior sheathing I would use Zip Panels taped carefully for my air barrier then I would use 1” Polyisocyanate insulation over the outside of the sheathing , then I would use furring strips over that and then the siding. For Insulation I would use densepack cellulose or wet spray cellulose. For the roof I would use wood trusses, very simple trusses, just a single roofline. (I would specify a 5-7” energy heel). Install trusses 24” OC then put a layer of 1” isocyanate under the bottom cord and tape the panels to make an air barrier, then strap the ceiling perpendicular to the trusses with 1X3 and drywall over that. Use R50 of cellulose blown into the attic. (with the iso this will get you a great insulated wall/roof). If you concern is tornados, build a safe room in the basement. Basically a concrete box. What are you planning on using the basement for? Eric


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21 Oct 2009 11:18 PM


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22 Oct 2009 06:19 AM
Posted By karlito on 10/20/2009 2:28 PM
My wife and I are trying to design and GC a simple 30x50 ranch w/basement house for an Iowa location.  We want to stay under 200K.  Our current thought process is:

 
 * 5 1/2" EPS steel SIP walls
 * Steel truss hip roof, vented
 * Would like a standing seam metal roof but haven't looked into cost yet
 * ceiling drywall on hat channels under trusses
 * 3" CC SPF sprayed on top of ceiling drywall
 * Speedfloor or some other steel / concrete flooring system with radiant heat.  Thus, entire basement
karlito;

you may want to consider steel sips roof in lieu of steel trusses as a more cost effective roof sytem

Dietrich's trade ready steel system can be used with plywood or steel pan/light weight conc.


Attachment: havian 004.JPG

Chris Kavala
info@southernsips dot com
1-877-321-SIPS
FL. Lic # CBC036455, GA Lic. RLCO000624, LA Lic. # CL33845
karlitoUser is Offline
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22 Oct 2009 09:06 PM
Thanks very much for the help!

Eric - We do not want to use any structural wood. Why would you use the beam instead of a bearing wall with two door headers? We want the most cost effective option.. including not having to get a crane for any part of the job. (Unless you think a beam and columns would be cheaper....do the columns not require as much extra slab support?)

Eric - thanks for the energy heel suggestion.  I read about that in the Alaska REMOTE system and it's something I need to look into more.

Eric - Upper level has master and laundry.  Bottom is 3 more bedrooms / utility / long 'multipurpose' room :)

Chris - I've been meaning to look into trade ready. Any kind of open joist that can span 15' and hold 3 inches of concrete, hopefully with no shoring, is great.

SimonD - Thanks for the post about the angle iron. A manufacturer offered that option as well as making your own z flashing. Wife doesn't like the z flash much and I don't like the angle iron.

However, we may scrap the SIPs all together. Reasons:

* Scratch estimate of CC Spray foam and exterior EPS/XPS is giving me $13K. That's doable.
* A more vanilla wall assembly (siding, strapping, XPS, Tyvek, Steel, 1" SPF flash in cavity, Drywall, Latex Paint) has proven (buildingscience.com) condensation control in my climate (cold and humid). Proven condensation control is more important to me than heating.
* Easier electrical routing
* Can probably get a light gage wall and roof truss kit from one supplier
* Flat surface (looks good) and no thermal break all the way down to footer (Excluding all the 12" OC strapping screws :()

Hopefully we can frame and do a lot of the dry in/flashing work and siding ourself. Theres a lot of info buried on the net if you dig deep enough :)


Eric AndersonUser is Online
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23 Oct 2009 09:12 AM

Ok

Given that you are adamant about  no structural wood, I would think that you are looking at several issues.  Since commercial buildings are built this way all the time, It should not be an issue. Find a supplier that’s ells premade kits for what you want if steel is the building method of choice. I guess I would look at something like the “Persist” http://www.homeenergy.org/archive/hem.dis.anl.gov/eehem/99/991108.html  or “Remote” wall systems  http://www.cchrc.org/App_Content/files/REMOTE8-2-06.pdf  for the insulation.

The advantage of these is the reduction of thermal bridges through the steel structure because most/all of the insulation is external to the wall cavity. If not alt least look into aerogel metal stud smugglers.

Given the no wood mandate, I would also consider doing the whole shell with ICF.  By my back of the envelope calculation, an ICF foundation and wall would be ~ 15 K each Plus footings and 2 poured floors  which you need anyway no matter how you do it.

 

As far as using laly columns instead of a bearing wall,   A column will likely require a footing that is  ~2’X 2’  a bearing wall will require a continuous footing.  The issue is insulation under the slab,  and with building sequence.    If you want continuous underslab insulation , you pour the basement walls to 9’  Then you back fill with gravel even with the footings, then your vapor barrier, then 2-3” of XPS leaving a small hole where the laly columns will go.   With this detail you can pour the slab in the basement when ever you want (after all framing is done).  This can make a difference in the plumbing costs because you can have the plumber do it all at once. (cost savings)

With a bearing wall, you pour a  continuous footing, then do the underslab plumbing, the put down the underslab insulation, then pour the slab, then put in the bearing wall, then start the first floor joists.  The slab will have to rest on the footing so there is continuous bearing from wall to footing so now you have a 18” wide strip under the slab with no insulation.  This is not good in living spaces especially with a radiant floor.

As far as needing a crane,  if you went with a steel beam you would need a crane, but the delivery company might have it with the truck anyway.   if you went with triple LVLs  2 strong people can put them in, one lvl at a time the bolt them together.  Alternatively, if your timing is right, you might still have the excavator on site and a good operator can place the beam with that. 

 

The other thing to consider is the cost of the shell is a small fraction of the whole building cost.  Usually less then 20% of the total.   Your biggest savings is in initial design and having less stuff.   I would build the house with all the plumbing centralized so you minimize dvw  and venting.  This can save big.  I would use acid stained polished concrete floors throughout, simple and cheap, (and good looking if done right).  I might use cork in the kitchen  so it is easier on the knees and feet. 

For the trusses, I would use one common truss.  Personally I would use a scissor truss to add some angle to the roof, but this increases your  interior wall and drywalling costs. 

IF you are being cost conscious, consider the following.

1.        Ignore the SPF and use cellulose insulation (unless you are concerned about this for other reasons) 

2.        Figure out how to use simple lighting.  For instance one easy way to light a kitchen is to use FL stip lights above the cabinets hidden by the cabinets  cheap, easy, efficient. 

3.        As far as finishes go, if you do the labor yourself, tile can be  very inexpensive.

4.        You can pinch pennies on cabinets if you are careful

5.        Laminate countertops are much cheaper then stone, you can also use granite tile countertops if you don’t mind the labor. you can do granite tile countertops for less then 10$ ft^2  if you do it yourself

6.        Plan on using minimal trim in the rooms, use drywall returns on doors and window openings

7.        Pick plumbing fixtures made by a reputable American company.  Buy them all from the same company ie Delta or Moen.  Ignore the European stuff, nice but pricy.  Use a simple finish, like brushed nickel.

 

Things you should not cheap out on.

1.         Windows and exterior doors

2.        Boiler with outside air supply

3.        Roofing

4.        Heat recovery ventilator.

5.        VERY Quiet Bath fans on a timer or humidity sensor

6.        Stove vent

7.        Toilets  Use Toto Drakes

8.        Plumbing fixtures

 
Also, don't underestimate the time it takes to build.  Mentaly prepare yourself to work on the house 7 days a week nights and weekends for a couble of years to realize you dreams.  Make a list of all the friends you have that have building skills and or are strong.  Plan on using them all, but rotate through them so you don't burn them out.  for stuff that requires lots of manpower like setting trusses or raising walls, make sure you are prepared ahead of time so when you have help, you can use it most effectively.
I know, I am moving in this weekend to my new house,  15 months and 3000 hours of labour and  after I broke ground.
The other thing i think is very important for owner builders it to make sure you are doing the framing and exterior work  when you have maximum daylight to work (and it is warm).  It is a big sprint to get the builidng enclosed and water tight.  Once you are dry and inisde, you can work off lights and a generator much easier.

Have fun and take pictures

Eric



Think Energy CT, LLC Comprehensive Home Performance Energy Auditing
John ClemUser is Offline
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02 Nov 2009 10:26 PM
Eric - excellent post, right on the money. Build the bones of the house right!

Karlito - ICFs are a great product, even for your climate. Combined with a well sealed and insulated roof system and good windows + doors, you end up with a very efficient house. Also very strong and quiet!

Several customers have done ICF/DIY homes by hiring a builder knowledgeable in ICFs and framing to get the structure up. This can be very cost effective if you have the time to commit to the project.

For cabinets, checkout Ikea.com. Great cabinets for low cost (large drawers are so much better than doors). Closest to you is Chicago or Minneapolis. I drove my wife all the way to Dallas to get her approval.

If you intend to be your own contractor, make sure all your subs are insured.


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dmaceldUser is Offline
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14 Nov 2009 11:14 PM
If you're not already, be aware of financing issues. If you are going to GC the house yourself, and plan to take as long as one year or more to do it, you are probably not going to be able to get financing from a bank. Not a problem if you have a $200k kitty available.


Even a retired engineer can build a house successfully w/ GBT help!
mapnerdUser is Offline
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06 Dec 2009 11:41 PM
karlito Where in Iowa? We're in Nebraska facing some similar questions. Having difficulty finding a GC and subs who think energy efficient. We're looking at either ICF's or poured w/external EPS for bottom level walkout and SIP's or 2x6/24" oc for the main level walls. Single angle shed roof (hope to do standing seam). Glulam beams with SIP panels on top for roof structure (no attic). We should compare notes if you're on the west side of the state. -Mike in Omaha


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