Erica Wisner

I do think that for your climate, the 8" heater would have given more insurance on those really cold nights. But you can probably still improve the situation with more insulation (we did R30 walls, R40 ceiling and crawl spaces ), maybe weather sealing, and by firing more often.  Try four hours morning, four to six hours evening, if it's not too inconvenient.

The 6 inch systems were originally developed as comfort heating for small huts and single rooms in milder, coastal climates. They do not typically burn enough wood to heat a larger space in more severe climates.

The choice to include Portland cement (which we don't typically recommend) may reduce your options to recycle the cob into a larger replacement system.

I also want to confirm that you insulated around the heat riser with some kind of refractory insulation. If it's just bare fire brick, I am not clear why it would be working at all, so I hope you already did this and it just doesn't show in the pictures.

If it really isn't working, one other option might be to look at removing and replacing the fire box with a rocket batch box. It is more costly to build, and takes more special tools and parts, but can burn more than double the wood, dramatically increasing your heat output. Look for discussion of these by Peter van den Berg and associates, on these forums here at Permies.com, at proboards, or at batchrocket.eu.

Before investing in big changes, you might check your heat loss situation to ensure that double the heat would do the job, or if you need o go even bigger.

You can check your heating situation on paper by using a home heat calculator like the ones at builditsolar.com, but a better reality check is to compare interior temps with desired temps, or to get ahold of an IR camera  and do a home energy audit. Or see if your county offers energy audits - some do, for free.
You want the IR camera to check for warmth escaping the building, which may reveal areas of preventable heat loss around windows, doors, rafters, ceiling and vents, etc. A better heat seal on the building could offer long term benefits, both for comfort and to reduce the total fuel burden for years to come.

Hope this helps. When you do find a good solution, please keep us posted!

Brick barrel vault ovens are lovely, but the proportions and performance are going to be different from a dome oven.

I would suggest looking into plans or books that are intended to be built with the types of bricks you found, as that will likely be far easier to build, with more predictable results, than adapting our dome oven proportions.

Building a dome oven with brick involves a lot of carefully angled cuts, and again, a plan that's been tested for those sized bricks will be far smoother to build.

If you have fewer than 200 free bricks, you could also consider just using them for the floor (alternating the wedge angles up and down so the result is flat on top) and following the original plans for the earthen dome.

For an example of differences in proportion:
Kiko Denzer worked out that the door height should be about 62% of the total interior height of a dome style earthen oven for good heat capture.  I don't know what proportion should be used for a barrel oven because the proportions of volume to surface area above the door would be different. A lot of barrel ovens I've seen don't even have a separate height door lip or end wall, it's all just the same height tunnel, and the door covers the end.
I think barrel ovens were more common historically in places that were doing high volume baking, and would have cared more about quantity than precision. One advantage of the barrels' rectangular floor footprint, without any restrictions from a smaller door frame, is it's easier to slide trays and paddles in and out quickly.

Also, our plans discuss the catenary arch shape for strong, self supporting masonry. But a lot of brick barrel ovens are a simple radial arch, which is easier to make with factory brick wedges. These circular shaped arches may need a little bit of extra weight or thicker side supports to balance outward thrust at the bottom (feet) of the arch.

Here is one forum where folks discuss a lot of different, modern backyard wood fired ovens, where you.might pick up some relevant search terms:
https://pinkbird.org/w/Types+of+wood+fired+pizza+ovens/363

Or you could just whack them together without mortar, light a fire in it, and see if you get roughly the results you want. Bricks are endlessly recyclable. Plaster some clay mud on the outside if you need it more airtight for a fair trial.  You can do this on a few square feet of non-combustible dirt, with a few more feet of safe space in front of the door to scrape out live coals.

I might suggest using your biggest pan plus at least a couple of inches as your minimum floor proportion, about 4 inches extra space at the door end to allow for different doors. Or look up standard catering/cookie sheet sizes if you hope to bake bigger in future.

Yours,
Erica W

I have to second the Daphne. Although it is not at all edible (foliage described as toxic to people and animals), I don't recall any other plant quite so romantically tantalizing me into wandering around following my nose, seeking the source of that magical fragrance.

I grew up around roses, Iris, lavendar, mints, honeysuckle, and sweet Williams (or clove pinks), so maybe Daphne got points for being new as well as smelling delicious.

The version I first met was in Portland's Chinese garden,  and one of the few things blooming in Jan/ February, so points for subtle standout there too.

Best smelling edibles I prefer: pineapple sage, pineapple weed, tea roses, lavendar, violets, day lilies. First and last three for salads or cream treats (like frosting cakes); middle three for teas.

Judith Pi wrote:

Marco Banks wrote:Would a retort burn barrel that creates biochar fall into that second category?  It converts waste into something that is ultimately saveable.  Once wood is charred, it remains for a long, long, long time.

I wish someone would create something small, portable, and easy to use in this regard.  ...
... Biochar-o-matic.

Hi all, new(ish) here (first time posting). Time to break the silence, as chance would have it, I just saw a YT video last night on how to make charcoal in your wood burning stove with a simple retort - a Gastronorm food container with lid Biochar-o-matic. In a video linked at the end he also does it with an old metal casserole. That way he also uses the gases of the charcoal to heat his house and stack a few other uses. https://youtu.be/jxBUqk2M3Y8.

Judith, thanks for posting both very useful tips!
The video link you shared offers a decent solution to the problem with many home biochar setups, which is the nasty waste and pollution from the pyrolysis gases. I've also seen Chinese food cart stoves that produce biochar, but this is a very practical option for most cool climate folks.
Anyone trying this will want to ensure the retort (pan with lid) fits appropriately in their stove, and will safely burn without causing creosote (as you might get from smoldering fires) or overheating, for their specific wood stove.  

Cider will definitely use a lot of surplus apples, and is easy to barter or convert to other products.

In terms of preserves, applesauce is OK, but I prefer to can
-apple pie filling (big chunks, just follow any pie recipe and leave out the butter, or use a canning recipe for apple or pear slices and add more cinnamon. acid/sugar and processing times are key to food safety).

-apple butter: fruit sweetened with apple juice if available. Easier to thicken slowly overnight in an oven, then add in more wet stuff again before canning.

Apple butter has more spices than traditional applesauce, and ours also makes a great base for BBQ sauce.

-Or you can keep going in the oven or a dehydrator with applesauce or apple butter for fruit leather if you want. Spices and some other fruits, like berries grapes cranberies and/or lemon, keep it more interesting than plain apple rings for winter snacking.

- chutneys: spiced fruit and veg condiments to use on meats or with cheese and crackers.  Usually contain vinegar which you can also make as already mentioned. Chutneys can be a good use of thinned or unripe apples, which can help the rest grow to larger size.

- cider plus: apple wine /hard cider is lovely and keeps longer without refrigeration. Depending where you live, it may not be legal to freeze or distill into apple brandy, but that stuff also rocks.
Taste batches before choosing which to ferment: musty or wormy flavors generally worsen, while tart or astringent flavors will generally mellow beautifully.  
Apples generally have plenty of natural yeast, but it depends where you are whether it makes a good wine, or is more of a bread yeast, sourdough, or skunky wild yeast. If in doubt, to avoid contamination by rotten spots or local molds, start by taking the juice, filter, boil, cool, and then hit with cider or champagne yeast to start a clean ferment. Protect from fruit flies at all times, also known as vinegar flies in the wine world.

There are some great recipes for spiced ciders and mixed fruit wines and meads.

All of the above taste great with pork.


Finally, social options (people as pigs? as more than pigs?)

If your cider processing is slow, apple season is a great excuse for a party to share the wealth.

Some areas also have gleaners' associations, who will harvest surplus foods for low income families and food banks.
Some food banks also organize volunteers to harvest u-pick donations.
And in some areas, I've known very cool orchard owners who create charitable programs to get fruit into schools for free, or sell it to support such programs, so kids aren't distracted from learning by empty stomachs.

Local kids may be willing to pick and help you store for small per-bucket wages and all the fruit they can eat. May lead to better outreach to a few working families, and more personal relationships than donations, if you prefer to support work and reciprocity.
Invite your favorite picker to bring 2-3 kids to do this together, the competition and camraderie will often enhance the results.
I've also been on the receiving end of adult deals, where I process excess harvest into storable treats, and split the results with the raw producer. A few deals like this and you both have sauces, cheeses, drinks, and all the party fixings for a luxurious winter.

Mother Nature often does let food go to waste/compost; but with an overproducing tree like domestic bred apples, that's a recipe for insect damage as mentioned above.
 In some areas, wasps, ants, deer, and bear will come for the surplus if it's left on the ground.  Horses can eat only small amounts, they are subject to colic/foundering if they gorge on apples. I think apple mash can be part of the cold season feed for cattle or buffalo, esp. as silage for cattle, but they don't prefer them in quantity like pigs do.

I have been disappointed by women's carhartts. The elastic seems to cut the life in half, plus they don't reinforce the top of the thigh and knee the way the men's carhartt's are reinforced. If you happen to find a very heavy women's cut carhartts, they might be worth a try.

I wear a lot of men's carhartt's, both light and heavy canvas. Ernie shreds them faster than I do. One surprising long wearing pair of pants for Ernie has been a pair of lighter weight, American-made, hemp fiber trousers.

My mother's go-to work and winter casual pants are flannel lined jeans from LL Bean. They are a good durable option. I don't love the heaviness; or how they feel when damp. I think I work in damp brush more than she does, she is more into smaller scale gardening and on-trail hiking.

I am also a big fan of thrift store and army surplus shopping for 100% wool, linen, cotton, hemp, or silk clothing, second hand. If you can tolerate odd colors or Grandpa fashions, you can sometimes find very durable stuff that way.  One long time favorite was olive wool Army pants with button pegged legs, the best for cycling in rain and misty weather.

That's an interesting comment about flowing water not freezing.
We certainly get ice on flowing streams and rivers here, though they don't freeze over until much later than ice hits elsewhere. So it can freeze.

And we certainly have good effects from running a pipe at a trickle of we're in super deep cold. But there's an extra element in that trick that I think most people don't think about; the trickle of water is coming from the source, usually at 55F, or 50F, or 10C, or whatever your average ground temp is. So it's warmer than any ice in the pipes! Liquid water is almost always warmer than any water in the vicinity that is trying to freeze (brinecicles excepted). So almost by definition, if you have flowing water, it isn't frozen.  

I believe there may be some physics that makes flowing water slightly slower to freeze- but when it does, it tends to freeze fast, as if supercooled.  Dozing ducks get caught with feet in the ice (though that may say more about sleeping duck reflexes than ice freezing rates).

I wonder if your floor system is recirculating the same water, it may not be as well protected as you think. It doesn't have that extra heat from the source. Though the pump probably generates some heat, and much of the floor is not that cold.  But if one side of the perimeter did get close to freezing, or below, it could effectively circulate that cold until it gets cold enough to freeze. I would imagine pipes freezing rapidly in an underfloor hydronic system would create an awful mess.

The source warmth of deep water sources, when contrasted with -20 or -10 air, was explained to me because it is used by orchards trying to alleviate ill-timed frost. They sometimes flood or spray with irrigation water, and run big fans to move the warmer (55 degree) air around to reach all the blossoms.  Spray and fans, not just for cooling anymore!  

Sorry, just caught that the Walker stove has already been chosen.

Disregard the bit about pipes under the floor, in that case.  There's not enough spare heat and "push" from the Walker style fireboxes to run much in the way of additional heating channels, unless you have an unusually tunable chimney.

The classic Franklin stove has a water tank in the body, which makes the stove terribly inefficient due to cooling the firebox.
I would prefer to see the water heating elements well outside the firebox area - the logical place on a Walker stove or most other rocket stoves is the cooktop-type area.
This raises the problem of just how much heat output do you want for cooking, vs. heating the floor.

As Satamax points out, you will probably want to cook for specific times, and this may or may not match the amount of heat you want to deliver to the floor.  
I like Kathleen's and Burra's screened summer kitchen idea.  As long as you have the option to cook outdoors, you can use the indoor stove more strictly according to your indoor comfort goals.

I might sic your engineer on calculating the total BTUs needed to heat up your various targets - get an IR thermometer, check the surface temperatures that work best for you to cook, and the temps you want to raise the floor mass to for comfort, and do some heat loss calcs for your coldest days using the BuildItSolar.com or similar home heat calculators.  You can convert that total heat (BTU or joules) to figure out what weight of wood you'd need to burn to achieve this, and what proportion of your heat needs to be available to cook, vs. heat, vs. keep the chimney working properly.  

It's all well and good to pick a compact stove for a small space.  But if it can't burn wood fast enough to deliver your total output, or if you want space for 3 pots but you also want to send 60% of the heat output elsewhere, you might need to pick your stove to suit the job rather than pile more jobs onto a cute stove.  
A dedicated boiler for a hydronic system is usually a reasonably large tank, with a lot of insulation, which makes it a somewhat ugly beastie that most people don't want in their living rooms.  Even if it doesn't explode, it creaks and groans and collects cobwebs.
If you want a cute and wood-sipping stove, get used to the idea that the heat will be uneven; there's only so much you can do with circulating a fraction of the heat from hotter to colder parts of the room, if the stove is originally designed to collect heat in a specific place for its own thermal performance.  

Walker stoves are designed to put heat out the top fast, and slowly out the sides, so they are great when installed roughly in the center of a space (as a kitchen island for example).
I've seen Lasse Holmes put a small bench on to capture waste heat from the exhaust on its way to the chimney - but you have to be careful how much heat you capture in this location, as the chimney needs heat to function (and these stoves definitely need a decent chimney to burn clean and draft well).

Yours,
Erica W

This content came up in a different discussion, so I'm giving it its own thread.

In climates where it gets substantially below freezing, sometimes it seems like if you want indoor plumbing, you have to choose between supporting the big mean utility grid, or never going away for a few days in winter.

A lot of folks dream of heating with wood, and growing their own food, but still want to shower and run a washing machine instead of hauling bath water around.

Neighbors and house sitters, or good drain and winterize options, or automated heat /heat tape ("energy slaves") are critical for protecting untended modern homes in very cold climates. If you like to travel midwinter, your home needs a different level of protection.

Some people think if you have wood heat, you can't leave in winter. If you also have livestock, it may be simplest to have a reliable person stay on the farm at all times anyhow.
But we don't keep stock, and we have heated with rocket mass heaters for the past 13 years or so.

We lived in the Okanogan Highlands, travelled some part of almost every winter for 7 years, and had 3 pipe freeze failures. (Four, if you count the trailer that one of our assistants lived in, which he left untended in deep winter to house sit for someone else.)
The thing is, only one of 3 pipe failures occured while we were gone.
Most times, we had family living nearby who ran the stove every couple of days for us. One time, something came up- I think it was medical? and we were all gone at once. That led to dripping when we returned, and then shutting off the house water for long enough to replace some shattered PVC pipes near the shower.

The other two pipe freeze events were due to:
1) the way the exterior run was put in the first place (far too shallow for the climate, because it had originally been under a manufactured home crawl space).
And
2) a well house pressure switch freezing up during a winter repair job; the pressure found a weak point of a prior repair, resulting in 6 hours of midnight.plumbing work as we had to.dig out the mud to get to the pipe before it froze.

I should give full credit here to Ernie's dad, who did most of the original work, maintenance, and emerency fixes, sometimes with our help.
And to local well repair savior Fred, who has not had a day off since his boss died, because he doesn't say no to emergencies like ours.  
His boss died in a car wreck the summer that drought followed a super deep, dry winter freeze. Our wells were #18 and 19 on their list of emergency repairs at that time. I wouldn't be surprised if overwork and fatigue were a factor in the accident, though nobody has said so.
Fred came out and re drilled our main well in the evening; he was doing his assigned customers in the day and his bosses' workload at night.

Plumbing is a good and vital trade to learn; if you can bear the workload, and bear to charge what your time is worth, it could even be a good living.
Given that a good plumber who follows local codes, frost depths, etc. can save you re-doing the work 3+ times, as well as prevent future emergencies that might cost more than your time, they are probably worth at least 3x your typical hourly wage.

Hard-freeze climates and shallow granite bedrock raise the difficulty of DIY plumbing to a whole new level. A few of our neighbors just more or less gave up on fully automated indoor plumbing all winter.

Instead, off-grid-ish folks may use indoor cisterns which can be filled with temporary hoses and pumps on warmer days, then drain and store those things indoors until next time. Most have a backup option to haul water from a frost free or well house spigot to the house.  

Underground cisterns are somewhat protected from freezing, esp with good perimeter insulation. The well water itself usually comes up at 50 degrees or so, so in large amounts it holds enough heat to stay liquid for a while. One family whose well never produced enough water hauls potable water from a neighbor to their own cistern; they drink boiled tea more than raw water.


Same freeze problems apply to outflow; two other neighbors had house-to-septic lines freeze last winter. They still has indoor running water, but no indoor drains.
Septic is harder to retro-fix, because the drain needs a specific angle to carry solids to the tank,. So if the system is too shallow, you more or less would have to raise the ground level, or rip out and reinstall the tank.  In both these cases, the too-shallow line goes under a driveway or carport, which adds inconvenience and expense to altering the ground level.  If it was just a backyard line, a couple feet of wood chip might be the cheapest fix.
The warmth of the water itself, toilet flushing, and the periodic warm water from showers, dishes, etc. seems like an important part of septic/drainage maintenance in cold climates. I'm told it's also critical to keep solids flushing well and/or cleaned out, as a partial clog can be a starting point for water to stagnate and freeze.

Some mountain folks do still use outhouses, or composter toilets, or trailers with tanks or chamber pots to empty, whether or not they have a septic system. County requires septic for permitted occupancy, so most go that route sooner or later.

Those whose plumbing works reliably in our climate mostly have wells drilled by local, experienced drillers, with insulated and heatable well houses for pressure tanks, switches, etc.

The pipes from well (or city water) to buildings are at least 5 feet underground. Irrigation systems and frost free hydrants mostly have their valves and drains about 5 feet down too. (The farm irrigation district winterizes its system every year, and doesn't provide water from October thru March most years. Our fire district winterizes all trucks that won't fit in the heated hall.)

Once the pipes emerge under the house, many folks either heat the pipes in the crawl space under the floor (heat tape is common). Some design the house to reduce the exposed pipe, maybe bring the pipes up directly into a heated home or shop utility space thru insulated slab floor, well inside the building perimeter.

If I was designing again for this climate, I'd like to make the primary wet wall relatively central in the house, back to back with the masonry heater.  I might also provide a shop space with a floor drain and frost free spigot on the downhill side of the house, and a way to drain the rest of the house in case of prolonged absences. Perimeter plumbing may be easier to work on, or to drain away leaks, but it sucks for winter freeze protection.

Trying to design solar hot water collectors and rain harvesting systems in this climate is very challenging. State of the art involves several years apprenticeship, usually engineering to set workable system goals and capacity, and then high tech, thermostatically controlled drainback systems, expansion pressure relief, as well as insulated and glazed collector box housings.  

Water harvesting from precipitation is more or less seasonal; any year round gutters, tanks, and filters need to be indoors, deep in the ground, and/or able to tolerate freezing at all exposed surfaces.  Temporary rain barrels, or greywater-like systems that harvest water primarily for gardening without a lot of filters and compications, can be easier to deal with and repair.

Speculation about other extreme, frost-prone climates:

Desert people get really good at recognizing and cultivating melons, cactus, and moist fruits and tubers... I wonder how much of our absolute daily needs could be met with biologically filtered water?  Soups, teas, fruits and salsas are hydrating.

I wonder if once you get up to permafrost territory, where ground temps average below freezing, if indoor plumbing is even worth the struggle. It's going to be an expensive and technical undertaking.  I imagine most people hire experts if they want it to work.

For off grid living, you might just get used to water in winter being something you store in solid form and bring to the kitchen to melt, like chocolate sauce or butter for popcorn.

What I notice in a lot of traditional cultures is, once a need or convenience gets expensive enough due to local conditions, you often see a "village" version.
A village Baker in areas with scarce firewood, where you bring your dough and pay a little to have it baked; the oven is way more efficient that way.
Most farmers here use a butcher/meat packer rather than set up their own slaughter and cool rooms for a few uses a year. It simplifies the hygeine issues. But electrical is cheap enough that most families have a big freezer.
Due to all the water challenges mentioned, most mountain folks in our area use the laundromat for at least a few months or years, while sorting out their own plumbing.  Some just go that route for long term. And many live with extended family or friends, a few little households per property, where they can share a well, garden or livestock care, a jaccuzi, or other conveniences.  Neighbors' helping each other is also common.  These arrangements don't always work perfectly, or forever, but they are valuable enough to be worth attempting and preserving.

City water and sewer are a larger scale version of this. It takes technical expertise to run them, but that expertise also helps avoid the terrible costs of disease and poisoning of the aquifer under everyone's wells. For larger settlements, water is definitely worth doing right.
In most urban areas of the US, it's legally required to go on city water and sewer within city limits, and the costs are charged to the citizens one way or another. Drainage of storm water, snow removal, and ditch and gutter maintenance usually also get organized at the city level.

Does anyone have experience with off grid homesteaders that decided to go village style, instead of rugged individualist, to pool their skillset and labor power?

Or with traditional villages, for that matter, creating particularly clever local infrastructure?

Tim Skufca wrote:we have a ground-source heat-pump which heats our hydronic floors from a well in our in-town Missoula well. In-floor heat is very comfortable. In the summer heat we circulate well temperature water through the floors to keep the space comfortable, which is very important if the Missoula air quality gets bad from forest fires. Closing the windows and running 55 degree water through the floors is an effective way to hold off those awful smokey periods.

ALSO: what is not talked about with Rocket Mass Heaters/Stoves is the necessity to be there at all times. There is no way to take off for a few days, or else everything freezes. I have the mind-set of embracing technology and install solar panels that power the electrically sourced hot water.

Again, in a 9a climate, you don't have the same freezing issues as in a 4 or 5 climate. Indoor plumbing for a 4b climate is a whole nother topic; but in my experience, a masonry heater beats any other wood heat for days you can leave the house untended before freeze-crunch. In those settings, you learn to invest in good neighbors, vacation-style drain systems, and/or heat tape.

In this case,
Climate sounds like it needs more cooling than heating. Shaded collonades, courtyard with fountain, or grape arbors are good. Run air through these spaces, draw it up into the main house by solar chimneys or wind scoops aiding natural convection.
If you have the option to run well temp water thru floor, why not? But it is more complicated than traditional methods. Air flow aids evaporation, which is a huge asset for cooling, unlike heating.

For underfloor: if you like digging, and you haven't hit bedrock yet, you can run the RMH pipes under part of the floor. Insulate wall perimeter, keep heater pipes at least 12 inches (30 cm) away from any combustible insulation.

Give yourself a margin of safety from the maximum lengths of pipe runs in our book, because you are in a warmish climate, and old and work-worn enough that you may want to run the heater when it is actually still warmer outside than in. I would take about 25% to 30,% off those maximum lengths, or add a bypass for chimney priming.
Use a vertical chimney, to about a meter above roof height, and insulated where it is exposed outdoors.

Since there is boiler experience in the house, I don't think running a pump and pipe system is beyond your capacity. You need to decide whether the heat exhange pipes will be kept potable, or non potable.
If potable, you can run well water thru them to a sink or other uses for cooling. But the heat exchanger run must not have dead ends, and must be careful with all heated water sources to avoid warm stagnation.
If non potable, you can run any old water thru, recirculate, or collect excess for gardens, until algae gunks up the works.
I like Tim's systems with an open pot or tank for the heater, which is non potable and easily cleaned out, and a coil in the tank thru which you run pressurized clean water.  This offers pressurized warm water with built in protection from boilover; reduces the stagnation problems substantially; and gives the option of running a shower or washing-up station off the same system, if wanted.
You could do the same for a solar collector tank, run separate heating coils to a tank and a potable coil for heat transfer. Many systems run water thru solar first to warm it, then use fueled heat to reach final target temps.

Again, pressurized usually goes with potable, because both require clean, alga and scuzz-free pipes. Which means precautions against warm stagnation in the lines. More options means longer pipes and longer stay times. If any loop is being shut off for weeks or months depending on weather, or for repairs and tinkering, it needs to be flushed and possibly decontaminated when re-activated.

However, I don't know if you'll produce enough extra heat off a tank on top of the rocket to heat the rest of the floor anything like the area just over the RMH ducts.  Might want the hydronic heated areas to be shallower, with copper conductors under tile, and better insulation.

 If you can live with hot, warm, tepid, and cool zones, like an old fashioned wood cookstove, then this sounds DIY doable for an old steam engineer. Cooling this way may produce floor temps that are not entirely comfortable while the air is still too warm, so a zone for chilling might be better than the whole floor anyway.

It will turn the entire space into a project, and one which may invite tweaking and improvements over time. If you tend to let projects take their own time, you may want a spare barn for overflow while tinkering,  since this is the primary utility room.

I would also not be inclined to pour solid concrete over everything, at least not without careful attention to cleanout access points. Discrete tiles or pavers may serve better, since you can bet that anything with functioning parts will eventually need inspection, cleaning, repair, or replacement. Just removing a bit of sidewalk that was mistakenly laid over a septic tank is a major hassle, which I would hate to deal with indoors.

This will probably be a sort of personal system, due to unusual features. I would not expect the next owner to want to operate and maintain it. So invest what effort and value in it you feel is worthwhile to please yourselves.

If you want zone control, where you can direct and dial the heating and cooling, or do that programmable timing stuff, I'd look for commercial products and an experienced local installer.

Please let me know if you'd like to hire us for a customized plan set or tech support.  Burra gets special rates. 😘

Yours,
Erica W