ricky_005
Basic Member
Posts:313
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| 01 Feb 2014 06:30 PM |
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I'm in the early design phase of a new residential home in Lagrange, GA for me and my wife. The home will be located on a heavily wooded lot (Termite Heaven) on West Point Lake. We are interested in building a Southern County home style slab on grade with a combination of lap siding and batten siding and a brick skirt around a 18" or so of raised slab. For protecting the exterior sheathing and studs I plan on using BORACARE in hopes it will keep the mold and wood eating critters out. Climate Data - Zone 3 We are looking at using James Hardie Board Artisan lap siding. Product weighing in at 4.55 lbs. /sq. ft.For the Batten siding would use the 4'x10' Hardie Panel. Product weighing in at 2.3 lbs./sq. ft. My main concern for a cement based product is its weight, and if you where to utilize 3/4" or greater Ridged Foam Board you are counter levering your siding on the fasteners. And the James Hardie Board Artisan lap siding is a heavy one. I do see a potential for the weight of the siding to cause the fasteners to sag or the wood at fastener penetrations to give away somewhat years down the road. If it where to occur, it would be a total failure for the siding as it would drop in elevation along the wall face in my option. I could install 1x4 batten strips over the ridged insulation with heavy duty screws maybe close to being like lag bolts, that might be the the right path. But what would be the best batten strip material for long term stability, longevity & shear strength? - 1"x4" Spruce?
- 1"x4" Yellow Pine?
- 1"x4" Pressure treated Yellow Pine?
- 5/4"x4" Pressure treated Yellow Pine?
- A composite material of some sort?
I've been thinking about a 12" double stud wall cavity with blown fiberglass or cellulose with no exterior ridged insulation would solve the problem but now I would have a expensive complex wall system with cold sheathing with high potential for condensation which will result in mold and rot. (I've seen it done up north which doesn't mean it's right here in the south) Would love to do ICF exterior walls, but for the area and surrounding home values, I would most likely take a brutal beating if I were to sell the home. Besides its going to be tough enough trying to hit our budget number. |
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Alton
Veteran Member
Posts:2164
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| 01 Feb 2014 07:46 PM |
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Dana1 is the most qualified to answer your questions. I did one house with cedar siding over 2" of external Styrofoam in Columbia, SC back in the 1970's. No problem with leverage. Cement board is much heavier than dry cedar.
I think the safest route is to use furring strips outside the foam board attached with screws into the wood studs. With the rain that we get in this area, designing and building in a rain screen might be the best way to go. If concerned about 3/4" furring not being strong enough to hold the cement board, then consider using thicker furring strips or attaching the cement board through the thin furring strips to the studs. I think it would be less work to attach the cement board only to the thicker furring.
No doubt there are much better systems than the one you described but quotes will have to be obtained to see how they compare to conventional construction.
By the way, I am nearby in Auburn, AL. Feel free to e-mail me about alternative systems available in this area. Since I retired from teaching in the School of Architecture at Auburn University, I donate some of my free time to assisting homeowners and a few builders.
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Residential Designer &
Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period .
334 826-3979 |
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ricky_005
Basic Member
Posts:313
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| 03 Feb 2014 03:41 AM |
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Thanks Alton you where of great help  By the way, I did find a JamesHardie engineering document suggesting how they think you should go about installing up to 4" of ridged foam behind their products.
Here is a extremely energy-efficient house built for Habitat for Humanity and designed by Building Science Corporation. They are utilizing 4" of exterior foam with concrete lap siding...
Would love to hear from some creative minds to help break down the Pros & Cons in JamesHardies recommended methods. |
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Alton
Veteran Member
Posts:2164
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| 03 Feb 2014 10:24 AM |
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Ricky,
Search for "Plenum Truss" for images of modified truss for HVAC enclosure. |
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Residential Designer &
Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period .
334 826-3979 |
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Lee Dodge
Advanced Member
Posts:714
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| 04 Feb 2014 11:18 PM |
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Posted By ricky_005 on 03 Feb 2014 03:41 AM
...snip...
Here is a extremely energy-efficient house built for Habitat for Humanity and designed by Building Science Corporation.
...snip...
It is interesting that what they call an extremely energy-efficient house still uses a fair amount of source energy, 80 or 85 million BTU annually according to the article at http://www.buildingscience.com/documents/insights/bsi-018-westford-house/?searchterm=westford%20building%20america. That seems high for that size "super-insulated" house, but a lot of the estimated energy consumption is for "other," which I suppose is mostly appliance loads and hard to predict.
It looks like that house was built in 2007 or 2008, but they do not provide any actual energy use to compare with their predictions.
It is surprising to see that Joe Lstiburek is not a fan of solar PV, at least at that time. If that house was built today, it would be interesting to see if they would have done better spending some of their budget on solar PV and reducing some of the insulation expenses. |
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Lee Dodge,
<a href="http://www.ResidentialEnergyLaboratory.com">Residential Energy Laboratory,</a>
in a net-zero source energy modified production house
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ricky_005
Basic Member
Posts:313
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| 05 Feb 2014 03:50 AM |
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Concerning insulated sheathing there is obviously a limit at which the efficiency gain curve begins to flatten .... and your ROI time line begins to stretch out in terms of payoff. Knowing where you stand and choosing where on the curve to stop is a very important decision to make. It could turn out to be wiser putting that money into upgrading your HVAC system to the most efficient system available on the market. My plans are not to build a Net Zero home but a High Performance shell and invest in state of the art appliances like a Carrier Infinity 20 heat pump with GreenSpeed intelligence. We are talking about up to 20.5 SEER on cooling and up to 13 HSPF on heating. Only grip I have about Carrier's variable speed system is it will only power down to 40% of it's capacity. In my situation, I think powering down to 15% to 20% capacity would be ideal for our 3 zone home setup. The central Heating and cooling system will have 3 conditioned zones within the home. Ducts and Air handler will be in the conditioned space, and Air handler will be located in the center of the home for optimal results. The Idea behind the zoning for me, is to Only Heat and Cool those areas which are primarily being used when your home. For me and my wife our schedules match from day to day like most couples, therefor we only Need 1/3 to 1/2 of the home at a comfortable temperature at a given time. First floor- Right side of home will be the main living area, kitchen, office etc.
- Left side will be Master Bedroom 1, Bath & Closet
Second Floor- Master bedroom 2 in center area of home
Zones are the following- Zone 1 - Living Room / Kitchen / Dinning / Office-Bedroom / Laundry Room / Half bath
- Zone 2 - Master Bedroom 1 / Bath & Closet
- Zone 3 - Master Bedroom 2 / Bath & Closet (Not in Use)
Summer.............................................. CoolingWaking up, getting ready for work
- Zone 1 - setting changes to 70°
- Zone 2 - setting changes to 70°
- Zone 3 - setting changes to 70°
During the day at work- Zone 1 - setting changes to 78°
- Zone 2 - setting changes to 78°
- Zone 3 - setting changes to 78°
Getting Home from work- Zone 1 - setting changes to 70°
- Zone 2 - setting changes to 73°
- Zone 3 - setting 78°
It's bedtime- Zone 1 - setting changes to 78°
- Zone 2 - setting changes to 68°
- Zone 3 - setting 78°
Winter...............................................Heating
Waking up, getting ready for work
- Zone 1 - setting changes to 68°
- Zone 2 - setting changes to 70°
- Zone 3 - setting changes to 68°
During the day at work
- Zone 1 - setting changes to 64°
- Zone 2 - setting changes to 64°
- Zone 3 - setting changes to 64°
Getting Home from work- Zone 1 - setting changes to 70°
- Zone 2 - setting changes to 68°
- Zone 3 - setting 64°
It's bedtime- Zone 1 - setting changes to 64°
- Zone 2 - setting changes to 64°
- Zone 3 - setting 64°
I believe by zoning the home into 3 areas it should reduce overall power consumption quite nicely ..... As for the amount of savings at this point, all I can do is guess that by adding a zoning system based on my setup it will enhance the efficiency of the system even further by lets say about 15% to 20% conservatively?
As for solar Lee Dodge ..... I plan on designing the home for a solar setup. Everything will be in place for a solar system, it's just none of the hardware will be installed. At some point as the cost continues to fall, I'll pull the trigger and make the investment. If you have the cash to burn, any time would be great time to pull the trigger, but I think in my case where my budgets under $300,000 for my new home it would be better to invest in state of the art high efficiency appliances. |
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Lee Dodge
Advanced Member
Posts:714
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| 05 Feb 2014 10:15 AM |
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I need to take back my comment that the Habitat for Humanity home designed by the Building Science Corp. looks high on energy consumption; it looks about right. I just wish that they had provided some actual energy use to compare with their predictions.
Ricky, I think that your focus on an efficient A/C system is appropriate for LaGrange, Ga. Having a mostly unused second floor should allow you to let that space "float" in temperature, while you condition the first floor to your desired temperature. I don't understand why you want to cool off the second floor in the morning during the summer, or heat it during the morning in the winter. I would be tempted to let it float even more than what you have scheduled.
You and your wife obviously like it on the cool side, which has an energy cost in that location, but that is a personal choice.
Designing your roof angles for solar PV would be an excellent idea. Delaying putting in solar PV will likely cost you the opportunity to take advantage of tax and utility subsidies, but the initial costs of the system should be coming down. My PV system cost (installed in 2010) was reduced by 70% by the rebates and subsidies, although that reduction would be less today. |
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Lee Dodge,
<a href="http://www.ResidentialEnergyLaboratory.com">Residential Energy Laboratory,</a>
in a net-zero source energy modified production house
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ricky_005
Basic Member
Posts:313
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| 05 Feb 2014 10:49 AM |
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Morning time we are up and out of the house within an hour or so, HVAC system would adjust temps in all zones to the new programmed range for about 45 min in the morning if need. Might need to do the upstairs twice a day if required to control the humidity. I think the Carrier GreenSpeed thermostat controls have humidity sensors to keep humidity under control. Will look at all capabilities of GreenSpeed units at a later date unless someone out there on the forum has some experience and can briefly fill us in on them.
So the reason behind this is to circulate and dehumidify the air throughout the entire conditioned space of the home in the morning time. This may not be necessary its just a guess at the moment. Once we move in it will change somewhat I'm sure.
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Dana1
Senior Member
Posts:6991
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| 05 Feb 2014 04:54 PM |
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With even a couple inches of EPS on the outside of 2x6 cellulose-fill walls, with detailing to minimis thermal bridging and at least SOME consciousness of the solar gain aspects of the window size/performance/direction, the heating and cooling loads are probably going to be lower than the output of even the 2-ton Greenspeed (which isn't a cheap thing). With a reasonably open floor plan and minimal heating/cooling loads you can probably heat & cool this place reasonbly with two 3/4 ton mini-splits or a 2-3 head 1-1.5 ton multi-split, which will equal or exceed the efficiency of the GreenSpeed, but at something like half the installed cost.
The 99% & 1% design conditions in LaGrange are VERY temperate, at 23F& 91F respectively (https://www.acca.org/wp-content/uploads/2010/11/MJ8-Outdoor-Design-Conditions.pdf ) so with an ~R20-ish whole-wall type building envelope it's really a matter of managing the solar gains (particlularly on rooms doored off from the ductless heads) to limit the room by room cooling loads to get a small right-sized ductless solution to work well.
Georgia Power is a statewide vertically integrated electric utility monopoly that intends to stay that way, owning or controlling all power generation on their grid. They have thus far succeeded in making privately owne rooftop PV somewhat less than attractive financially, but mostly through dodging tactics and getting cozy with their regulators, disallowing third party owneship models, and offering less than favorable net-metering structures. But they've managed to tick off everybody from the Green Party Left to the Tea Party Right with their pre-financing their nuke project construction with ratepayer surcharges in advance of actually putting them in service. Given that the lifecycle cost of PV at 2014 prices is below the 10.5 cent/kwh retail rate (and even less than the per-kwh FUEL cost of nuke), as the cost of PV continues to fall I suspect their current business model won't cut it by 2025, and if the state regulators get their act together, privately owned grid-attached PV will become a fairly compelling investment well before then (like it currently is in Texas or California.) Designing the roof pitches and orientation for PV is the right thing to do on any new construction, but in the GA case it's probably worth waiting until either the PV prices crash further, or the regulatory environment changes (both of which look pretty likely.) |
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ricky_005
Basic Member
Posts:313
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| 05 Feb 2014 09:26 PM |
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I'm not a fan of mini-splits for two reasons - Bad Aesthetics
- Uneven room temperatures
Yes the GreenSpeeds are very expensive ... I believe Carrier distribution network is like most HVAC manufactures, they only sell to Carrier dealers. This is something I need to dig into about how to side step the retail Dealer/Installer. I will be installing the duct work and a sheet metal shop will make the plenums for me. I will also need to hire a helper which may or may not have HVAC experience but what I need most is just helping hands at a low cost. I have enough knowledge and skill to perform the install of the plenums and flex duct myself. The hookup, testing and tuning of the HVAC system I will let a experienced Carrier HVAC tech take care of it when hes off the clock on the weekend. I expect by doing it in this way will lower total cost significantly. I will know just how much it will lower my cost once I find out about how to side step the dealer. The smallest GreenSpeed unit is 2 tons and with it only capable of powering down 40% a 2 ton unit may be a bit to much for the home, will find out once I get into the HVAC design phase.
As for solar gain, the house orientation will be Front facing north east. That would be between 30° to 40° rotaction off the east or west axis. East and west side combined may have 2 or 3 small windows nothing to be overly concerned about. The south side should be fine. The rear of the home facing southwest about 50% of the windows will be under the rear porch area. I will be clearing all trees from around the house by about 60 ft. in all directions because they are to darn tall and some of the huge pines have what I think loggers call cat faces which weaken the tree close to the base of the tree. Another reason for clearing the trees is its a narrow ridge I will be building on so I have to clip the top of the ridge to have enough area for the building slab. I really hate having to take all the trees out but I do have the intent of replacing them with hardwood sapling. With that being said a decade or two there will be shade trees around the entire home again, they just wont be Pine trees but Oak trees. As for Solar, you are right about Georgia and this is one of the reasons why I'm not that motivated about solar and when I bought the lot it was at such a great price I pulled the trigger and also knowing that solar power generation would not be very favorable because of the lot orientation. I hope one day to have PV panels but pricing needs to improve along with there efficiency. I do see a day where power companies will be charging home owners a monthly service fee for net metering/line maintenance ect. Will have to wait and see whats happens in GA over the next decade. For the time being I will build the home as efficient as I can for what money I have to invest. Lot Plat with test mock up showing orientation  Google Sat .... Termite Heaven  Looking down center of ridge (southwest direction) from front of lot ....  My buddy the squirrel again  or is that a Prairie Dog in Georgia  |
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ricky_005
Basic Member
Posts:313
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| 07 Feb 2014 09:21 AM |
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@dana My corrected response to your suggestion about mini splits ... I might end up having to go with one if my cooling load turns out to be estimated below 2 ton's. The 3 zones I intend on having the unit setup on, I think will need to power down quite a bit more than 40% like the Carrier unit if its only conditioning mainly just one zone. Mitsubishi and a few others manufacture make a standard typical air handlers that are compatible with there mini split compressor units. Here's a home with a Mitsubishi HVAC system with typical air handler. http://www.youtube.com/watch?v=vie4kHN_iYUIts a home Matt Risinger built and I think its a 2,000 Sf. home, if so why the heck a 4 ton compressor in TX? |
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sailawayrb
Veteran Member
Posts:2283
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| 07 Feb 2014 06:37 PM |
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Your buddy is very cute! If you think JH siding is heavy, try installing Old Kentucky Log concrete siding sometime… I don’t think you can go wrong by following the JH installation guidance. They have great products and they provide great technical support too. |
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| Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do! |
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ricky_005
Basic Member
Posts:313
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| 07 Feb 2014 07:30 PM |
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Posted By sailawayrb on 07 Feb 2014 06:37 PM
Your buddy is very cute! If you think JH siding is heavy, try installing Old Kentucky Log concrete siding sometime… I don’t think you can go wrong by following the JH installation guidance. They have great products and they provide great technical support too.
Wow great idea... watched some videos of Old Kentucky Log siding, Amazing stuff. |
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