800 sq/ft pasive solar house first experiment seeking advise.

I am planning to start building in spring-summer 2017. Right now I am gathering knowledge and developing my plans. I want my design to be completely holistic but also beautiful.

I have developing plans on my own humanure toilet, Rocket Mass Heater, cabin layout including passive solar elements, and permiculture garden although that is my weakest point.

I am young and have several years of scattered maintenance experience and am currently gaining a year of wood frame construction experience. I acknowledge that I probably know just enough to be dangerous but I am confident I can muddle through. I know there will be problems though so I beg this very knowledgeable community to point out some of my mistakes or things that I haven't thought of yet.

First question should I post all my different design elements in their specific threads like RMH and composting toilet? I am kind of hoping to get feed back on how everything will work as a unit.

Keep in mind that I am still in the idea phase. If I don't give specific measurements it may be I haven't gotten around to crunching all the numbers. But my vision is starting to take very clear shape as I tweak this or that element.

So the crazy ideas I think I can buy 1-2 acres in Maine, USA Start milling some lumber in fall or winter when the sap has started to leave the trees. Let the wood dry and work all winter saving money for necessities like a well and solar power for electric tools. I want to build an electric shed to house all my solar system and then run power to the house later.

I would work part time and camp on property as soon as it warmed up enough in order to make money for materials. Recently I have started thinking of making an insulated sleeping trailer instead of strait out camping. Part of the functional design I am going for is with the idea that I may want to move or leave and do something else like peace corps in a few years and leave the property as a rental or even to keep doing this and set up a series of incredibly well made, affordable rental properties that teach people about sustainable living. I am going to put up all my plans and documentation in the hopes that eventually it evolves into a good enough idea that many people want to copy and improve it.

I am planning to build off of insulated concrete forms. I know concrete has a higher price and less green footprint than materials like cob however I am trying to get the very highest quality and also pick and choose my battles with town/state code, as well as be able to use similar models in other locations around the USA. I am thinking a 20 by 30 or 40 foot house I went up from my initial thoughts because I wanted to be able to offer my mom a room if she needed it. The design centers around a large central space kitchen, living room, and RMH dead center. The RMH is central because I originally wasn't planning passive solar and thought I would need a robust heating system and because I want to make it an attractive centerpiece. Luckily as I have started researching Passive Solar I realized I could make it double as an effective thermal mass for the solar gain and cooling mass in the summer. A question I have though is I think a stove pipe going up would spit the very large open feel I want to go for and I am worried that the horizontal distance for the pipe might be too much. I plan to raise the kitchen on a false floor and run my exhaust out the side. I got the idea that I could get away with this because the ehaust runs back and forth sidways in the bench before being vented but I suspect I need to be careful any thoughts?

I want to set the Humanure toilet up on the "Second Floor" or loft space this is so that I can create an external room accessible only from the outside for the compost receptacle. This is so that If I rented I could come every however many months grab the box with a dolly and take it away from the house to the compost area without the tenants having to directly deal with it, essentially making it feel like the flush toilets they are used to. Now I have an odd idea here I was thinking of making the composting bin out of well crafted joinery possibly avoiding nails. The idea being that in addition to proper composting practices like regular addition of course material for proper aeration and per use addition of plenty of carbon I would also have a designated area where the compost could do its thing for the 2 or more years while the wood broke down. Buy the time the wood is also earth I plan to prove through lab testing that not only does it hopefully go through the thermophilic bacteria process but also the long and effective process of patient and over the top long composting. Idea being that I can prove that if the person waits till the wood is weak enough to put a shovel through it is then 100% as safe as regular soil to put on vegies time after time. Research my prove me wrong but my reading suggest that eventually I may be able to really fight the main stream fecophobia.

As a design twist I want try and keep all my plumbing except maybe my bathroom sink in the center of the house to avoid accidental freezing of pipes and so that I don't have to run as much piping. The sink on a center island connect to the RMH with some homemade stone and mortar sheathed cabinets. Not sure what counter Possibly slate as I may be able to find large pieces to put together from the local abandoned quarries. The shower I'm playing with the idea of building a small tower like room right next to the RMH and sink, a wall to hang my indoor herb garden from. This is a lot of weight in the center so I am thinking of supports underneath (entire rough cut tree with footing under concrete slab) and I was already going to shoot for going above the structural standard for the size of the floor joists. I am willing to take suggestions on building dimension changes I should probably cut back from 20' span but I don't want to make the walk ways or the space in general feel tight. I want to stick frame the roof to give the center space a vaulted ceiling and to provide more vertical space for rooms or storage on either end.

On one end long ways I will have the door come in from the west side of house narrow side into a little mud room. I hate being cold so having a airlock is kind of important to me as well as a place to stop the mud during mud season. On the north wall in this very small space will be an artistic stone mosaic thermal mass for the large window to the south. Bench to the south possible also a thermal mass. I want to put recessed rigid foam wood overlay sliding panels on all my windows to trap heat overnight.

Trying to decide what stairs will look nice meet rental property codes and not take up too much space.

I don't know what to do for the garden but I know I want a well rounded permiculture design.

I look forward to your help and criticism, this project is going to happen I look forward to seeing what type of learning experience it will be.

Since passive solar involves the entire house envelope and configuration, this is probably a good central place to collect your plans. Individual components like the RMH should be in their respective forums, with links to and from here. It could get really confusing to have discussions of several different elements interspersed with each other.

I am not familiar with the specific Maine climate, but I suspect it doesn't get much more sun than here in south central NY, and you will really need a solid heater at the center of your house, supplemented by the solar heat in sunny spells and spring and fall.

First question should I post all my different design elements in their specific threads like RMH and composting toilet? I am kind of hoping to get feed back on how everything will work as a unit.

I agree with Glenn. Your best to figure out the specific elements in their respective forums (where you can draw on the people who will respond to those threads but not necessarily on this one), and then bring your design together better later on.

Lots of interesting ideas here, Elias. Some similar to my own.

My own plan is to start building this year, using standing dead beetle killed pine. My plan is to go modular, beginning the house by building a Solarium, which will eventually be part of the South wall/South room of the house. It will have a rocket mass heater as part of the solarium's North wall (which will eventually be shared by the living room as a sort of Trombe wall), but this wall will also hopefully have a sliding glass door, and a bunch of operable windows (that will be able to be opened but will always bring light into the living room). I'm building it slowly, one room at a time; that way I keep the project small/manageable.

Glenn Herbert wrote:Since passive solar involves the entire house envelope and configuration, this is probably a good central place to collect your plans. Individual components like the RMH should be in their respective forums, with links to and from here. It could get really confusing to have discussions of several different elements interspersed with each other.

I am not familiar with the specific Maine climate, but I suspect it doesn't get much more sun than here in south central NY, and you will really need a solid heater at the center of your house, supplemented by the solar heat in sunny spells and spring and fall.

Thank you both, I will split up the elements and post in some more categories.

Do you happen to know if you can have too much thermal mass? I have been reading about passive solar and have learned that too little is very bad but I don't know if there is a point where you should avoid overdoing it.

Do you happen to know if you can have too much thermal mass? I have been reading about passive solar and have learned that too little is very bad but I don't know if there is a point where you should avoid overdoing it.

Thermal mass can be tricky. The thing about it, from what I understand, is that it is a long term storage of heat. The heat goes in and absorbs slowly into the depth of the object. It will radiate this heat back out, but it will also radiate it, or conduct it, behind and underneath it. This area behind it or under it is also thermal mass, and that can amount to a positive effect, but if the mass is extending outside, for instance, as a stone wall that has no insulation behind it, and is then open to the air, or a stone wall that is buried straight into damp earth, like in most root cellers, then a lot of the thermal potential is being leaked outwards away from your interior structure, and is not returned. In the case of the rootceller, the idea is not to have the heat build and radiate, but that the depth of earth keeps the temperature moderate. An uninsulated stone wall serves, like adobe, or other such structures, to moderate in different ways then what most modern temperate ideas of what thermal mass is for. In that case it takes in some so that the room doesn't get too hot, and releases some when the room is cold at night, but it doesn't retain all the heat, and it doesn't give all of it's heat into the building. It radiates in both directions.

In Hait's PAHS model, the earth around the house is covered with a waterproof membrane (which he calls the umbrella), so that it stays dry-or dries over time-and thus retains heat in it's dry mass and re-radiates it back into the interior. Hait also recommends insulating this space from the air, under the umbrella membrane. In his design he charges the extended area around the house with warmth via heat exchanging tubes as well. He is maximizing the thermal mass potential, for Passive Annual Heat Storage.

I have heard that 7 inches of thermal mass is very effective if backed by an insulating wall, in a greenhouse north wall. The 7 inches takes in a good amount of heat, building up in it's mass, and then radiating out into the room when it is needed at night.

You want the thermal mass on the wall/floor inside the house where the sunlight is hitting. It would be best to only have the water pipe on 1 shared between the bathroom and kitchen.

If you are afraid of your pipe bursting just drain your pipe and 'composting bin' before you go on vacation.

in regards to my post above and this quote:

Do you happen to know if you can have too much thermal mass?

So like anything and everything in permaculture.... the best answer is 'it depends'. It depends on your climate and your goals for the thermal mass.

I'm already in Maine doing generally the same sort of thing (or, well, gearing up slowly to do it...going to be a while yet). I'm sitting on roughly 14 acres in the southern part of the central highlands / penobscot valley area on a beautifully damaged piece of stump-land with gentle south-facing slope and copious amounts of clay (cost was ~$17k w/owner financing).

First, a bit about what we're planning for our passive/RMH heated home:

We're looking to use cob since the clay is already here in large enough quantities - have been in the experimental phase, working with the cob to do cordwood/cobwood and RMHs. We brought in a 26ft 5th wheel camper trailer to start with while we learn the properties flows and get things set up. The "cabin" comes later as we get the materials ready and have enough knowledge/experience to finally start building, not to mention get the site ready which is going to be quite a job in and of itself. Already, we've gone through several iterations of design and the latest and greatest design is a very "holistically designed" passive solar home. See the on-paper sketches here: https://permies.com/forums/posts/list/40/32322#387386 Funny thing is with each iteration of design, it became more and more "organic" in feel, eventually resembling one of nature's marvels - the bat.

So far, we're looking at simple roundwood timber framing using primarily hemlock from the property, plus some of the fir and pine, maybe some sugar maple here and there. We thought about using strawbale for some of the walls but it's just too darn expensive up here ($6/bale or more) and quite difficult to work with compared, so we're sticking to cordwood infill. Our experiments with cordwood walls, using cob mortar, have gone fairly well, though the old "good hat and good boots" thing is even more important in such a wet climate. We'll be shooting for 24" thick double (M-I-M) walls for those exposed to the outdoors.

The structure is meant to be built modular as well, which is a very good idea from a sanity point of view. Likewise, your raised kitchen idea is something we settled on as well - a large bump of thermal mass that's charged over the summer with greenhouse air then further "recharged" as necessary with RMH exhaust seems like a great idea. We're also looking to incorporate "RMH beds" and baths sunken into RMH mass. In essence, the entire place is a series of mass benches inside an insulated envelope.

In trying to maximize the solar heat gain, the "batwing" shaped structure acts as a sort of sun-scoop to aid in the passive heating feature of the structure while also allowing for 2 separate living quaters (bedroom and bathroom) with shared "community" kitchen and lounging area. Front and center is an attached greenhouse/sunroom/solarium (with not one but two RMH exhaust ducts running through the growing bed! Take that winter ). The exterior northern side(s) are then wrapped by a shed structure with the south-west and south-east exposures wrapped with porches which can be converted to additional "sunrooms" with plastic wrap for the frozen months. These exterior structures add a sort of envelope structure around the entire unit that will help buffer the -20*F temps we generally see in Jan/Feb in these parts. The entire structure is earthen floor and timber framing posts are simply charred/treated and sunk into the ground to avoid any needs for what could qualify as "permanent foundations" (see below).

Another huge factor to consider with a more passively designed home in Maine is how to successfully and safely hold on to and utilize the massive snow pack we often get. From late January to middle March, the snowpack is generally between 2 and 5 feet - that's a lot of good, free insulation for your roof if it's designed to 1) handle and hold on to the load and 2) not turn it into a sheet of non-insulating ice through heat loss from the interior. In the RV, we find an enormous difference in indoor comfort levels with just 6" of fluffy snowpack on the roof. For this, we're going with a sod green roof 12-18" thick with 6-12" of loose hay insulation underlayment (between waterproof membranes) - the idea is to have tall grasses and the like up top to hold the snow pack in place during the harsh winds we do get. In addition, the structure will be backed up against a wooded area that will help buffer the stronger north and northwest winds.

Now, I have some notes I want to pass along regarding doing stuff like this in Maine for cheap and without running into headaches with the depts of making you sad. Number 1 is to really go over the laws and rules before even buying land. Start at the state level and hope that you can end it there. Much of the best part of this state is unincorporated with the rest being nearly so. That means the state laws and rules regarding building and code are what will inevitably apply. It also means resources being stretched much thinner to come out sticking noses into what you're doing. If you buy land in one of the "richer" communities along the coast, or where there's a lake with postage stamp lots along its shore...or, god forbid, you go looking for something down near portland/augusta...you're going to be facing all sorts of headaches regarding building codes and nosey local code enforcement officers. In essence, once you've invited them out (or they've invited themselves out), they're going to be in your life forever. They'll know you, know what your land looks like and know what you've done since their last visit. If they never have reason to come out for a looksie, quite often you don't even exist on their radar.

You can get beautiful, fertile land along state maintained, paved roads, with DSL/cable/power available and friendly but stick-to-themselves neighbors, for literally "dirt cheap" in areas with little to no local government - that can save you A LOT of hassle when looking to do things that code enforcement wont understand (RMH, passive solar, etc). More land than you need is better on every level, too - don't limit yourself to "1 or 2 acres". Get 10 or 25, or 50 - it wont cost you much more out here but will give you a heck of a lot more flexibility and freedom.

The keyword up here is "stump-land", which is code for land that's been logged with less than ideal practices and is now going dirt cheap because they've mucked it up so badly and don't expect to get another harvest for 40 years or more. These usually come with decent enough dirt roads/driveways for access, slash piles ready for huglekulture, a whole assortment of native berries growing on the land and years worth of RMH fuel in the form of birch, sugar maple, beech etc coppice. You'll find the land rutted up and muddy, and stripped of any valuable timber, but with clearly marked boundaries and (rough) access roads running throughout.

Now, the state law reads something like "hand carried water" requires no septic but with a cistern (over X gallons...can't remember the exact figure, but it's way low), a well or any other "automatic" water delivery system (pump from lake/river, etc) you will need at least a gray water system. Rainwater catchment or wells with hand powered pumps do not require this as long as there's a "hand carry" aspect to it

Last I checked, composting toilets are simply illegal in the state except for one very specifically detailed design of composting toilet, which must be manufactured by a company with approval by some body or another, and that toilet does not actually exist. It's stupid, but true - I think it's something like a specific placement of a supplementary compost material feed to the system which must exist, but no commercial model has one. The state is ok with simple pit outhouses (which must be permitted and inspected) or collection tanks (such as come with an RV) that you service or have serviced (there's a free dump station in Bangor, btw), but otherwise you're required to have a septic tank and leach field. As a side note here, one piece of land I looked at in a "richer" town demanded I provide receipts for RV tank service on a quarterly basis in order to not have approved septic tank / leach field installed.

Regarding the need for building permits and the like, structures that require one are very loosely defined in the state law. The most important rule for qualifying a permanent and taxable structure (which then must also have a septic system, building permits, code inspections, etc) is that it have a "permanent foundation". Sono-tubes and cement piers are exempted from this in the state law, as are simple stone corner pads used in log cabins. Mudsills, gravel/rubble trenches and skids don't qualify, of course, though a frost-wall will qualify and a full basement or even concrete slab qualify. There's a gray area with dry-stack stone foundations and pads used for timber frame posts - seems they do usually qualify those as "permanent foundations".

If the structure has wheels, it must be registered for the road or it will be taxable and require all the craziness and code enforcement, too. I've heard about one couple who built their home on pontoons, in a dry field, to skirt the rules since it's technically a house boat with no "permanent foundation". There's also a guy who winches his home, on skids, down onto the ice for the winter, then back up to the shore for summer, to ensure he never has to deal with the code enforcement craziness

Knowing the laws and rules, and finding a place where they're minimal (unincorporated or nearly so) can make natural and alternative building here in Maine very easy, but if you're not careful, you're stuck with basically the requirements you'd be looking at in NYC. The greenies did a number on this state's laws which is only now starting to be fixed - they may have meant well (I personally agree with a lot of their message) but they had a terrible way of putting that stuff on the books. Definitely do the research before you buy anything so you know what you're getting into. Anonymous, generalized calls to the town hall when one does exist can help in huge ways with making decisions.

Oh, and consider the tree-growth, open space and farm land tax programs - they're on the books for a reason and might be the only thing the greenies did right Maine grows trees and forests well, and that's one of the biggest financial benefits this state has. If those trees are high value timber, or those forests produce food, fiber and fuel, they still qualify and meet the demand we have for commercially viable forested lands and should be on the books as such, helping prove to the world that such types of programs are beneficial. Basically, rather than "paying" farmers to grow corn and soy, here we can "pay" farmers to grow acres of black locust, nut pines, grapes and black cherry

https://permies.com/t/54570/composting-toilet/Humanure-composting-toilet-bringing-progress#450510

The beginnings of my humanure composting toilet tread.

I'm moving down to 600 sq/ft. Does anyone know in stick framing rafters what is the maximum unsupported span for say a 6 by 12? In other words what will I need in Maine where there is a lot of snow to bridge 16-20 ft. Moreover I am kind of married to the vaulted ceiling and sleeping loft idea but I am worried how it will effect my heating in a passive solar/RMH heated house.

Rather than trying to clear span a 20' structure, I would suggest running a beam lengthwise with two interior posts, and having easy smaller rafters. You would need some interior posts to support a partial loft anyway.

I have a 12' long 8x12 beam supporting a total interior clear span of 23'. (All white pine, and 4x10 rafters @ 24" o.c., up to 14' spans.)

For insulation in a northern climate what should I shoot for in my walls. I am planning on a staggered wood frame design. I am thinking of rock wool insulation for the many benefits of safety and efficiency, ease of install, etc. I could do 2X4 framing with a total wall rating of 30 two R15s or I could do 2X6 framing R46 two R23s Plus I am planning on an external wall wrap like an r3 foam-board. Is R46 overkill or will it save me on power and heating in the long run? Whatever the standard good enough rating is I would like to exceed it at least slightly.

I have started my to scale drafts. This is the first floor I have the kitchen and RMH pretty well planned out but am still deciding on windows and the uses and layouts of the rest of the small rooms. Basement and loft will be coming shortly. Each square is 4 inches, three squares is a foot. Right now the outside walls are 2X6 staggered which makes a 1ft think wall not including siding and paneling. Depending on what I decide for insulation I may bring it down in size and gain a few inches on the internal plan.

I find that when starting a project layout, it is more flexible to do very small-scale sketches (often on grid paper with say two feet to a square); this lets me make sweeping alterations with a few pencil strokes, and keeps me from getting invested in details too soon.

Drawing out detailed sections by themselves to be sure how much space a certain element requires is a good idea. These detail sections can be referred to in overall sketches with an outline block that can easily be shifted as required.

"...On one end long ways I will have the door come in from the west side of house narrow side into a little mud room. I hate being cold so having a airlock is kind of important to me as well as a place to stop the mud during mud season..."

My companion's house in Canada was modified to have all entrances at a lower level than the floor level of the house, so that any cold air that enters when the doors are open pools in that lower area.  This design choice was inspired by Eskimo igloo entrances, which essentially function in that manner.  Here's a representation of the concept (Thanks to ScoutLife Magazine for the image.  https://scoutlife.org/hobbies-projects/projects/6793/how-to-build-an-igloo/)

Best wishes on your project.  We will be starting a similar project (hopefully next spring), so I'm now following this thread with great interest! [Edit:  Just noticed that this thread is 6 years old.  Would love to see reports of any progress you've made!]

Elias Twitchell wrote:I am planning to start building in spring-summer 2017. Right now I am gathering knowledge and developing my plans. I want my design to be completely holistic but also beautiful.

Since Elias started this thread in 2016, I wonder how his passive solar house turned out?

That is about the time we finished ours.  That mudroom concept sounds great for colder climates.

Did the mudroom concept work as expected?