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Point me in the right direction, small, new, energy efficient home

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by juanni, Dec 2, 2012.

  1. Como

    Como Minister of Fire

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    Regular Concrete is 0.08R.

    Concrete with 6% bubbles should be higher.

    That number seems to come from one source and must be a major typo.

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  2. Como

    Como Minister of Fire

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    The wall in front of me is about R30. If I was building now I would aim for R50. They are forecasting -17F as a low on Sunday, but we will have lots of sunshine during the day. So heating load would be minimal during the day. You do not have that. I know that today the House was fine until the sun started going down.

    From a heat sink point of view I think you would be better having the concrete on the inside as that is where your heat source is.

    Your initial total for the walls makes sense to me with about 50% extra in the roof.

    If you then do a heat loss calculation you should find your peak demand at 10,000 or so for the house which makes a heat source fairly minimal. 3KW in electricity terms as a max.

    I do like the ability of a stove a bit too big to put out a lot of heat and take a room from 50 to 70 very quickly.
  3. pdf27

    pdf27 Member

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    Why? Insulation is pretty cheap, and you only pay for it once. Additionally, better insulated walls mean you don't get cold surfaces with the associated convection currents and hence draughts.

    If I were doing the building in that situation, I'd be planning on the R54 as an absolute minimum and looking for more if possible. It doesn't cost you all that much, and if you get it right (which requires a fair bit of attention to detail and a proper heat load calculation) then electric convection heaters become an economical way of heating. That has a lot of advantages (cheap, low maintenence) and the total cost of insulation + heaters will probably be getting close to that of a lower level of insulation plus a hydronic heating system of some sort.
  4. Frozen Canuck

    Frozen Canuck Minister of Fire

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    Agreed. We typically gets SIP's here that yield R44+- in a 6" panel, however you have choosen to go with tilt up concrete panels in your situation. If you are still in the planning stages SIP's are pretty DIY friendly. A couple can take a 2 day course & learn enough skills to DIY the wall panels in that time. Pretty straight forward in most cases & you only need 1 special tool (beam saw) for cutting the panels on site, or you can order them precut for assembly according to your drawings. I agree with the comment about your situation being right for installing a gasser in your shop & piping the heat from there. Best of luck with the project.
  5. juanni

    juanni New Member

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    I think you missed my reasons for wanting a hard rock concrete exterior. :)

    1. Peckers would make SIPs look like swiss cheese in a couple of seasons.
    2. SIPs would require a hard rock stucco finish, something I can't DIY and there is no one locally who can either. I would have to pay transportation, lodging and living expenses for anyone that would be working here more than a day = $$$.
    3. It isn't very fire tolerant, and I live in the woods.
  6. Have you considered fiber cement siding? Not saying tip up concrete won't work but it seems like a lot of work to reduce fire risk. And 'out of the box' house construction generally leads to lower resale values if that is a concern.
  7. juanni

    juanni New Member

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    Actually I think it is going to less work and headache especially when you look at long term maintenance, material storage and repair issues.

    I can have the premixed sand/ag delivered by the truckload. It isn't a propriety product, can sit outside year after year and doesn't deteriote. Ditto rebar, mesh, galvanized studs, galvanized floor decking and plate embeds that I fab myself.

    The portland cement obviously would need weather protection and does have a shelf life with absorbed moisture.
    Admixures need protection from freezing.

    The wall panels, shell etc could sit for years uninstalled or erected without deteriotion worries.

    The proposed wall panels 9' high x 12' wide are load bearing, high thermal mass, prefinished except for paint and caulking around the perimeter, impervious to bugs, birds, wind, water damage, fire and typical sized falling trees.
    Requires zero maintenance other than paint every 10 years and that perimeter caulk every 30? or so.
    Other than the insulating foam (I may go a different route) there is nothing to burn on the entire structure = no fire insurance required or very low cost = total that up $$$ over a lifetime.

    I don't have to drive 65 miles to a town, Home Depot, Lowes, whatever, only to find out the screws, nails, Simpson connectors, ICF block, SIPs panels, siding or fill in the _____, is out of stock, ordered the wrong size, putting a stop to the project.

    I don't have to look for anyone qualified or skilled to help with any part of the project except perhaps the alt heat and drilling the well.
    And I don't need a "crew" to pour and finish a 2yd panel, or to install it. Me and someone that can work a concrete rake and a garden hose to clean the mixer and tools every 5 days or so. Even that is hard to find!.

    All at an estimated $3 or less per sq ft of wall panel.
    What other system comes close?

    Finally, I guess unless you have lived in a remote, sparely populated, rural area, you have no idea how difficult it is to get materials, help, contractors, etc.

    Anything that I can do that eliminates someone, some product, or weather dependent DRAMATICALLY saves time, money and frustration.

    Incidentally, I stopped by one of the plumbing supply places in town and they have a guy that designs hydronic floor systems.
    So I went back to his office to talk to him.
    I told him of my building plans and was thinking of a hydronic floor system and what would be some good heat source options.
    Gas or electric he said.
    I said what about wood?
    His reply "you don't want wood".
    Asked further he said it is a lot of work, and that he doesn't know anything about wood boilers. lol

    That is why I am here.
  8. Dextron

    Dextron New Member

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    I would like to give you a vote of confidence, respect and encouragement. I took on a similar project in building a house in a remote area and doing all the work myself. One person who keeps at it can complete a purely amazing amount of work over time. If you take the time to research things you can do just about any phase of construction and do it just as well as the professionals. I am sure most folks on this forum are the do it yourself types and I mean no disrespect towards any of them but taking on a large project in a remote area by yourself is a whole new level of challenge. It is very satisfying to see the end result and know everything about how it went together and know you did it all yourself.
    Best of luck and I am sure your project will turn out fine.
  9. benjamin

    benjamin Minister of Fire

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    Lots of us have built houses "outside the box". By that hydronic design guy's estimation we're all crazy for using wood boilers. So don't let any of us stand in your way.

    Some people have recommended the whole nine yards boiler, storage and backup in the shed to feed a small efficient house. This is nuts. Such a system will work great with that setup, but it makes no sense when a much simpler and cheaper system will work just as well.

    I have no experience with tilt up concrete and we have no idea how much experience you have with this system or construction in general. So we're kind of guessing, but the points about resale value, difficulty etc. are valid. Frame construction is easy to do for people with minimal education and motivation, alternative methods only get harder.

    edit: or if you're building over time, concrete blocks instead of tilt up?

    The thermal mass that's outside of the insulation is useless (unless you have desert sun or big daily temp swings). If it was me, I'd be putting the concrete inside, a larsen truss with 8-12" of cellulose, and stucco on the outside. Stucco is not that hard to do, especially if you don't need it to look a certain way.
    Taylor Sutherland likes this.
  10. Como

    Como Minister of Fire

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    MgO SIP's would be wood pecker proof.
  11. pdf27

    pdf27 Member

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    One other possibility if you're looking at blockwork construction - cavity wall insulation, which is very common in the UK. It's basically a masonry-insulation-masonry sandwich.

    If you're building it by yourself I'd certainly have a think about blockwork rather than casting panels in situ and tilting up, if only because the lower weights you'd be handling are easier and safer than whole panels. Each of your suggested panels (5" x 9' x 12') looks like it will weigh almost exactly 3 tons, so you're going to need some sort of crane to lift them into position unless cast in place. If something goes wrong with weights like that and you're trying to manhandle them it can be very dangerous indeed - and from the sound of it you're a long way from help if you need it.
  12. Como

    Como Minister of Fire

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    Celcon type stuff AAC would be easier and has thermal benefits, but it is not widely available, certainly not available in Colorado
  13. juanni

    juanni New Member

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    Steel tilting form with overhead crane, all in one. Will have its own axle, wheels and four 20K? landing gear style jacks.

    Place and level form directly in front of footing.
    Cast the panel, let it cure 5 days or so.
    Whole form tilts up so there is little stripping stresses on the panel.
    Strip panel from form at almost vertical position.
    Roll panel into position using overhead crane.
    Weld base connections and brace.
    Lower form until wheels contact ground.
    Roll form/crane 12' over to next position.
    Raise form with jacks and level.
    Repeat.

    The beauty of precast is modular panels, of the same size, same reinforcement, same embeds cast over and over. With window and door openings of course.
  14. juanni

    juanni New Member

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    I would be curious what the cost of equivalent of 18, 9'x12' of those SIP panels delivered to 59801 would be.
    I bet it would not be a economical alternative.
  15. juanni

    juanni New Member

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    Thank you Dextron!!

    It wasn't relevant to the topic when I started this thread about alt heating, but I am a licensed PE with a few years of exclusive precast design experience (commercial structures), plus several years of wood frame design, a few ICF projects, was a contractor before/during engineering college, and before that a carpenter.

    Currently my hobby is metal fab/machining/welding.

    It is going to be OK. :)
  16. Como

    Como Minister of Fire

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    Winter is coming, 10 as a high tomorrow and -18 as a low.

    We are currently renting a house while I work on the Hotel 4" SIP, slightly bigger than your proposed building. All electric plus a wood stove.

    I brought 2 cord over from the Hotel, and so far I think that is going to be enough for the winter. Our electric averages less than $3 a day.

    I built the Boiler building using SIP's, the only issue I had was with the supplier, a long story. I also used 4" but instead of OSB I had them in MgO, cement board for want of a better description. If it had been a house I would have gone to 6". I modularised the design so I used 4'x8' panels. Still needed 3 of us, 4 for the roof panels. I am sure OSB would have been a lot lighter. They can go up very quickly.

    AAC is autoclaved aerated cement, light weight concrete blocks but with better thermal protection and can be worked with hand tools, I would have used them if they were available. They now use thinset for mortar to minimise joint thickness which would be a thermal bridge.

    I looked at the Passivhaus etc standards, and I can see that in Germany they might make sense. But going the extra costs a lot and when you compare it with the cost of putting one more log on the fire when you are surrounded by the stuff, makes not a lot of sense.

    Now if you want a Boiler system etc, well go for it it. But I just can not see the economics. A stove has much less to go wrong and is not power dependent.
  17. juanni

    juanni New Member

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    But see Como, you are pointing out the issues with alternate construction materials that I am trying to avoid.

    Problems with the supplier, 3-4 people required to install, products that aren't even available in a far more populated area than where I live and (I assume) unfinished exterior surfaces with lots of joints.
    And we haven't even considered the total delivered costs.

    And I will have a wood stove or fireplace in the house, only I don't want to have to use it for primary heat source. I will use it for the pleasure of a fire or in an emergency, but I simply do not want the mess of beetle killed wood having to be constantly carted into the house and having to feed a small stove.

    Out in the shop mess isn't a issue, IF I decide shop boiler route.
    And it sounds like I may have to feed it once a day, feed it for one day or maybe every other/few days.
    Plus it can supply my DHW and I have to have a stove/fire in the shop anyways.
  18. pdf27

    pdf27 Member

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    That makes a big difference - I didn't realise you've done this before quite a few times! Given that and if you've got cheap/free wood available, the proposed design makes a lot more sense.
  19. Floydian

    Floydian Feeling the Heat

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    Hello juanni,
    It looks like you live in a 7700+ HDD (heating degree day) area, is this correct?

    I agree with this, first and foremost, and before you build.Run the calc based on whole building assemblies that account for ALL thermal bridges, the bane of any super insulated building.

    There are a lot of ways to achieve tight, super insulated construction. This site discusses most: http://www.greenbuildingadvisor.com/

    In your climate zone these would be my absolute minimums:

    r-5+ windows-this means triple pane, warm edge spacers. Think about the minimum operable windows you'll need for summer time ventilation and fixed units for the natural lighting you will want.
    This can save a bundle and and perform a lot better than lots of operable units. South facing units should have a higher solar heat gain coefficient(SHGC) if possible, even though it sounds like you will have minimal solar gain.

    r-20+ sub slab insulation, higher for any slab edge detail. Dow Thermo-Mass could work well with your proposed wall assembly.

    r-40+ whole wall assembly. I wouldn't count on much r-value from your exterior concrete so you see this can be tricky. Your right about SIPS-definitely one of the more expensive super insulated wall assemblies for a DIYer. GBA has good info on virtually all high performance wall assemblies, as well as BSC-building science corp. Check them out if you haven't.

    r-60+ Are you going cathedral or attic? Vented or unvented? So many ways to construct these assemblies it'll make your head spin. See the above sites.

    Air tightness of less than 1 ACH/50 is doable with good detailing, and definitely heat recovery ventilation-HRV.

    If you insulate to these levels your radiant slab will hardly feel warm in all but the coldest weather. Panel rads, as Bob Rohr suggests, with a floating cork floor over your slab would achieve every bit the thermal comfort of a heated slab the with the added benefit of getting you off of the brutal hardness of concrete. A unheated cork floor can actually feel more comfy than a heated slab in a super insulated house because it conducts less heat from your feet. And I see no benefit to the thermal mass of the concrete if you don't have good passive solar potential. A btu is a btu, after all.

    Just some thoughts. Good luck,

    Noah
  20. juanni

    juanni New Member

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    Yes that is the HDD for Missoula the closest recorded data that I find.
    I am about 50-60 miles away, 200' lower in elevation and have none of the howling winds that Missoula gets because they are located out in a treeless plain.
    But I don't get the winter sunshine either.

    And yes I will run a heat calc, but I haven't even finalized the floor plan yet,,,, or designed the walls (I suspect 4" concrete will be adequate) or anything else.

    I came here for ideas about the alt heating. :)
  21. Floydian

    Floydian Feeling the Heat

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    I consider proper passive solar design couple with super insulation+tight construction the ultimate alternative heating system.;)Or the ultimate alternative to complex, expensive heating systems that, IMO, are hard to justify in homes built with low long term energy usage as a priority. Obviously this is your house, so your priorities are all that really matter.

    About wildfires: It is my understanding that when a house is subjected to a wildfire, the windows tend to go pretty quick and at this point it really doesn't matter what type of cladding the building has.
    Just wondering if you can shed any light on this scenario for me?

    Not sure 4" of concrete will keep the woodpeckers at bay!;lol

    Noah
  22. Frozen Canuck

    Frozen Canuck Minister of Fire

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    Honestly I think Bob Rohr gave you some great ideas. Given what you have said about not wanting the unit in the house, I will assume that your shop will be the new boiler room. Given that, your choices are really unlimited (sorry to say). Any of the boilers that members are using will work in your shop. Once you have a practical load number to use as a base you can if you wish decide/discuss how often you want to feed said boiler. Daily like some members without storage, or add storage & go further between firings. Enough options at this point to make it confusing to say the least. Once you have load info I am sure members will provide plenty of boiler options. There are a few geothermal threads in the green room if you are considering that option as well.
  23. juanni

    juanni New Member

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    Well as noted way above in this thread, solar isn't a viable option.

    As far as wildfires, I am building away from trees of any size that might fall burning onto or near the proposed home. No brush around the house either.
    The big risk would be falling sparks and hot ash landing on/near combustible materials. That is why I want no exposed combustibles or even unexposed.

    I have burnt massive piles of slash and brush from clearing the property, cutting down dead beetle kill etc,,,, the heat really goes up, 25ft away or so there is no real heat, so I can't imagine anything hot enough to fracture out a window, and if it did what would burn on an all concrete and steel home?
    The foam, behind the sheetrock, behind the metal studs, behind the Roxul,,,,not likely.

    Oh, and I expect those peckers to try to knock a hole in the concrete or even just enjoy banging their heads against it.
    But it isn't going to look like this 4 year old existing well house.

    [​IMG]


    That jammed in tin and paint can lid are covering the large holes.

    You fellas, the carpenter ants, the termites, the black mold and the peckers can have my share of the Beaver Board, warping, cracking, 3rd growth, wood products, I have seen the light of concrete and steel. :)
  24. Fred61

    Fred61 Minister of Fire

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    The woodpecker pecked on the school house door
    He pecked and he pecked "til his pecker was sore
  25. Como

    Como Minister of Fire

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    AAC is not a new product, I used them 30 odd years ago, just not made in Colorado. Stocked by the Home Depot equivalent. If I was going it alone I think I would go ICF. Your system is Concrete and insulation. The size of those panels would scare me.

    So a Stove for the shop where you do not mind the mess. A friend who has a large house well insulated uses wood stoves in the house and propane in the shop as he is in randomly and a stove would be not practical.

    I think when you do the calc you will come up with a small heat load that will make any wood based boiler system overkill.

    One of the problem with in floor radiant is that it is slow to respond, but your case seems a situation where that is not an issue.

    Or you could look at baseboard radiators, not the fin stuff but the ones that replace a wood baseboard with an emitter.

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