Aaron Yarbrough

I think it will work. If you calculate the total weight of the building and get a rough idea of your soil class you can figure how big your piers need to be. Just make sure you get below frost depth.

We built a 16'x24' timber frame cabin on piers. Here's our pier detail(note there is about six inches of compacted gravel below the pier that's not in the detail):



I used this table for the determining soil class.

I agree with R Scott that you need to think about the foundation of your existing building. I've seen a house with a slab and grade foundation pull away from it's porch built on piers.

Here are the calculations I made for our our cabin for reference.

Jonathan of The Tiny Shiny Home YouTube channel posted a video called Composting Toilets are a WASTE of TIME this week. I watched it and it made me a little angry.  The straw man arguments he made I found really infuriating. I'll put a link to the video at the end of the post and summarize the arguments in my rebuttal.

Background: Jonathan has a family of six. They started using a Nature's Head Composting Toilet in 2017 while living in an airstream trailer. In 2020 they moved the trailer onto raw land in Arizona where they continued to use the Nature Heads while building a hyperadobe home. Jonathan built a composting toilet system on the property composed of 5 or 6 50 gallons barrels with urine diversion. I think the idea was that once a barrel became full you covered it and moved on to the next barrel. He said in the video that that experiment was a failure.

Argument #1/Hot Take: Composting Toilets are huge time sink
In the video there's a montage of Jonathan cleaning the Nature's Head Toilet and emptying the urine collection. I think the lesson here is to size your system appropriately. With just one collection vessel using a Nature's Head for a family of six is going to be a lot of work. You will be emptying and cleaning the collector at least every other day. I know a family of five who uses a Joseph Jenkins humanure system with five gallons buckets. They change out buckets every other day but they have a lot of buckets so they do a bulk empty and clean once a month.



We use a similar system at our house. With two adults it takes 4-5 days to fill a five gallon bucket. When a bucket is full I put a lid on it, put it in our bucket holding area, wipe down the toilet seat and drop in a new bucket. I have eight buckets in circulation so I empty the buckets into our compost bin and clean them about once a month. The process takes about half an hour. I haven't cleaned a flush toilet in a while I think the time commitment is comparable.



The willow feeder system is even more time efficient because it uses larger collection vessels and skips the step where you empty the bucket into a compost bin.

Argument #2: Composting Toilets are a long term commitment
I agree with him on this point. When constructing a house it is a good idea to think long and hard about how to future proof it. In our case, I installed a toilet flange and plumbing necessary to install a flush toilet if necessary. We have a septic system sized for a flushing toilet (per county requirements).

Argument #3: Composting Toilets can be problematic with a not fully on board partner/spouse
If you can't tell I'm a bit of a waterless toilet aficionado. My wife is not as enthusiastic about the in and outs of human "waste" management but we have a compost toilet that's fairly low maintenance, looks nice, is comfortable and most importantly doesn't smell. I believe that if you create an elegant system you can win over just about anyone except for probably your county health and human services official. If you're married to your county health and human services official I guess I can give you a pass on this one.

Argument #4: Composting Toilets don't handle diarrhea or vomit well
I disagree. Paraphrasing Uncle Ben here, "With great amount of liquids comes proportional amounts of cover material,"  and Saint Peter, "Wood chips cover over a multitude of sins." And with projectile vomit you get the added bonus of no toilet water splash back.

Argument #5: Composting toilets are awkward with guests and often end up in disaster
We have a short set of instruction posted on our toilet seats and have never had a disaster much less any issue. Even if someone chooses to defy the sit down to pee rule that little bit of excess moisture has never been a problem.



Argument #6: Composting toilets are ideally suited for one to two individuals and/or infrequent use
I agree that the Nature's Head Composting Toilet is ideally suited for one or two people. However, you can size a waterless toilet system to fit a wide range of users and usage patterns. The Willow Feeder at basecamp in Wheaton Labs is a good example. It sees some periods of pretty heavy use. We sometimes have long term guests expanding our effective household to 3 or 4 and our five gallon bucket system is flexible enough to handle it.

That's the end of arguments against composting toilets. I think it is a pretty weak foundation to make sweeping generalizations from. What really bothers me is that loads of people will watch that video and not think about it very critically because it confirms their bias. Thanks for the rant space. Here is that video if you're so inclined:

Welcome to Permies! 16 acres is quite the palette. Looking forward to seeing what projects you get up to.

Our guest cottage has a living roof and is partially earth sheltered and that helps some with the temperature but humidity is still an issue that I haven't found a way to mitigate apart from using mechanical ventilation. The good thing is that it doesn't require much energy to keep that space comfortable. We're able to power the cottage mini-split and our main house unit with solar and battery storage.    

I found the book Gaia's Garden really helpful and inspirational when I just getting interested in homesteading.

Growing micro greens, fermenting and soap making are all pretty accessible homesteading projects.  Even if you're not in your forever home I think starting a garden either in container or in ground is a good idea.

Both below and above ground I like to insulate the hot water line especially on long runs. PEX will shed a lot of heat.

I second Martin's suggestion not to bury any connections.  

All of the structure's load is on the fasteners which is problematic.  

Jackson Bradley wrote:
I am a fan of notching. It is not difficult and can even be done with a chainsaw if you are good with one. If the notch will remain exposed, I use a skill saw and Sawzall to make them look good. If they will be covered up, I use a small battery powered chainsaw. The chainsaw chain makes a rougher edge on the notch and is not as visually appealing as the skill saw method.

Also, if your fasteners ever fail, the beam is supported by the post. If the beam is attached to the outside of the post (no notch) and your fasteners fail, it could cause some serious issues.  

I agree, either notch your posts or double up your rim joist and use a post to beam bracket. Here is the sub-floor design for similarly sized structure (12' X 16') I built recently using the latter option:

larry kidd wrote:It got down to about 20f last night and I never insulated or heated the batteries. Lost power about 2:30am took till about noon to get the cells warmed up to about 35f or 2c and got power back online. Spent the better part of the day after that wrapping the cells with heat tape for pipes and put insulation under and over , still need to go back and insulate the sides. Used 30 feet of heat tape with a 90w draw. It has it's own thermostat on at 35 off at 50 if I remember correctly.

That's good to know. I thought lithium batteries would just not charge at low temps. I didn't know discharging would be affected as well. My batteries are in the same insulated enclosure as my inverter and it seems like the inverter puts off enough heat to keep the battery above warm.

So, to give everyone some closure on this this thread I completed this project a couple of weeks ago (just in time to claim the solar tax credit). Here are the details:

I ended up replacing my Magnum charge controller/inverter. That decision ultimately came down to the relatively low inverter power output (4400 watts). I want to have the option to use induction cooktops in our home/cabin and in the guest cottage (Currently, both have propane ranges). I didn't completely math it out but I felt the cooktops combined with the convection oven and the HVAC systems systems would be too much for the Magnum inverter. The new Sungold inverter can output 10000 watts.

I now have two strings of modules  increasing my generation from 3.8 kW (12 modules) to 6.5 kW (18 modules). I ended with 6 extra modules (3 old(320W) & 3 new(400W))

While assembling the 16 kWh Lithium Iron Phosphate battery I broke one of the terminals on one of the EVE cells. I couldn't find a welder to reattach it so I drove to Houston (~200 miles) to pick up a replacement cell.  While I was at the warehouse in Houston I bought a fully assembled 15 kWh Lithium Iron Phosphate battery. This was a day after I had found out one my FLA batteries had a bad cell (See previous post) so the latter purchase was a bit of panic buy. It also seemed like a good opportunity with the volatile tariff situation to get a low cost battery and not have to pay shipping.

Here's a vlog from the upgrade project:


Addendum:

As projects beget projects I found myself with extra solar panels, an extra brand new Lithium Iron Phosphate battery(see above), some functional 6V FLA batteries,  and a used but perfectly good inverter/charge controller so I built a solar/firewood storage shed. And because I feel like I have to justify owning a chain mortiser (and more so because I like the aesthetic) I made it (hybrid) timber frame. I also have been wanting to play around with linear actuators so I installed an adjustable pitch racking system on the roof. Here are some vlogs from that project:

Beginning construction


There are some intermediary videos but here is the wrap up:


Next steps involve learning how to safely climb trees do a little surgical canopy pruning to provide to deshade the modules in the afternoon.

Thanks to everyone who commented for all of the tips and advice.



   

Jackie Lei wrote:Yes, LiFePO₄ batteries really are a big step up. I’m also planning to upgrade, I’m looking at a 16 kWh LiFePO₄ battery for my home loads. The price is surprisingly low, just a little over $1,200. A friend recommended this battery manufacturer to me since I’m not very familiar with LiFePO₄ products myself.

This is the battery I’m considering. Could you help me take a look and let me know if the lifespan can really reach 10 years?

I usually wait for Will Prowse to test and break down a battery before I buy it.