Tiny house build in Hokkaido

Gerry Parent wrote:

Peter Sedgwick wrote:My question is how much is enough gravel? I’ve read that we should have 6”/15cm under an earthen floor. Is this accurate?

.....and I have read that 4”–8” of drainage gravel was the recommended amount to use. Such a wide margin as to the soil type and climate I'm sure.

I’m not sure I understand exactly how the drainage gravel Inside the room functions. If there is a perimeter beam foundation trench filled with drainage gravel how could water even get to/infiltrate the drainage gravel inside the room? It would have to travel up through wicking?

The gravel needs to be washed? I read stuff like this. “ The big thing is that none of these "washed gravel" sizes should have fines in them. No dirt, silt, clay or even fine sand. You want discreet stones that have a bit of airspace between their corners once they're in place. It is the airspaces that promote drainage. If the airspaces are filled with dirt, it doesn't drain as well. The fine dirt also wicks water up from below, defeating the purpose of the "capillary separation" that is intended with the gravel.”

Mr. Yoshida says that water won’t be an issue in this soil type and that the type of gravel is not that important. He’s suggesting a vapor barrier and not to include carpet, as the carpet will promote mold spores.

I’m a bit confused as to what the “right” thing to do is.

Any thoughts Gerry?

Peter

Hey Pete
Drainage layer is the capillary break like you mentioned coming up from below via wicking. Doesn't matter how much you protect it from the sides, the earth is deep! So this stops most of the water but then there is the water vapour that evaporates upwards as well you need to potentially stop - This is the function of the vapour barrier Mr. Yoshida recommended. He has a point in the carpet potentially getting moldy. I don't have first hand experience so I don't know for sure. I do know however that carpet is sometimes used as a layer on a living roof but then that's also outside away from the living space.
Each area is different and so what works in one place may not be the best for another.
I see Mr. Yoshida as a treasure - Like your very own personal Matt Walker to help guide and direct with local experience with the land.
Perhaps he doesn't have the imagination and creativity that Peter & Co. have, but I can see that may be your gift to him?

I have read about washing the gravel too. Again, I think it depends on how wet the soil can get and how effective you need the gravel to be to do its job.
I don't think there is such a thing as too much overkill in a foundation anyways. A redo in this department can be very heartbreaking knowing that you could have prevented it.

The "right" thing to do is always what feels correct for you. After all, its your project, your triumphs and also your mistakes...but then, as the famous painter Bob Ross said many times "They are not mistakes, they are happy accidents". So you get to see it as you wish!


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Also, don't make the mistake of not protecting from under like Burt Gummer did!

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Words of wisdom as alway. Thanks again Gerry. Really appreciate the time you take to give us advice and insight on all the details of our projects.

A redo is the last thing I’m interested in for sure.

Will leave as is for now. On to some block work stating tomorrow. Hopefully we can bang this section out quick and get into framing in the next week or so, depending on weather.

Mr. Yoshida is gold for sure. He’s 81 and no matter what the topic of conversation he always is somehow able to relate that back to a man’s penis size. Fun for all...🥴

Will keep punching away.

Cheers, Peter👻

Having a wicked time with these sting lines. The foundation is about 3.5cm out of square. All the sides are the proper length, but the rectangle is skewed so I’ve got to bring it back before we go any further. Doing this with string, suspended in space, is proving to be nothing short of a challenge.

The fight goes on...🌞

I know all about obsessing over making everything perfect while building many stick frame houses and sheds over the years when dealing with conventional materials, but for a natural house, imperfections are kind of the norm.  I know you want to do nothing but your best with this construction, and it shows with all your hard work and dedication but don't let it rob you of your creativity by remembering to keep be out of the lines every so often!  :)

Gerry Parent wrote: I know all about obsessing over making everything perfect while building many stick frame houses and sheds over the years when dealing with conventional materials, but for a natural house, imperfections are kind of the norm.  I know you want to do nothing but your best with this construction, and it shows with all your hard work and dedication but don't let it rob you of your creativity by remembering to keep be out of the lines every so often!  :)

I hear ya loud and clear and I’m with you all the way. I’m 100% on the arty farty tip with the overall look and feel of the building. It’s just the “ah it’ll be alright” is what gave me the the 3cm Discrepancy in the foundation. Now I’ve got to make up for that in mortar on one end of the wall to get it back to level. I may be a bit of a perfectionist at times, however I don’t feel good with compounding issues that rear their ugly heads further on in the build. Once the stick frame is up and straight the cob covered façade can be all lumpy bumpy and most like will be finished with lime plaster polkadots in the end.

You can have an abstract expressionist painting, but if the frame is crooked there’s more of the likelihood it’ll fall off the wall.

Guess that my Philosophy in a nutshell for better or for worse.

Peter👨🏻‍🔧👨🏻‍🎨👨🏻‍🔬

P.S there still a 3mm discrepancy, after reading your comment Gerry, I’m gonna leave it there...🥳

First two courses of blocks are finally up. Took a while as we had to get use to the process and make up for a 4.5cm hight discrepancie between the front and the back of the beam foundation block. Now back to level and everything seems relatively straight. Final starting to feel more comfortable with string lines and understand where mistakes can be made and easily overlooked. The weather has been a bit sporadic as well, so constantly changing the mix to adapt to the heat and sunlight.

Will keep working away and keep updating as we go.

Hope all is well around the world.

Cheers, Peter👨🏻‍🚀

Looking great Peter!   Keep up the good work!
You'll be in your new home before winter!

Aloha my friends!

A much needed update on our tiny house adventure. We finished the foundation and most of the stem wall for now. I’ve decided to put the project on pause for the time being, leaving it in a state that won’t be effected very much by weather. Just came to the conclusion it was better to continue this project later, rather than trying to race against the clock to beat Mother Nature. And to be honest I’m glad I did. Giving me a chance to reflect on what we’ve done and where we need to go. Also giving me time to breath a bit. My body was getting worked from lifting and banging and digging etc.

We will be in the old house for the fall and then likely stay with the family when it gets too cold. Most likely shooting down to Tokyo for work from time to time in the winter for film work.

Many thanks to everyone who has shared their advice and insight thus far. The adventure will continue and we will keep sharing.

Peace, love and hand sanitizer...

Peter & Co. 🌈🖤🌈

When you speak of lifting etc, have you thought of using a simply crane system?
Either a long pole with a counter weight or a sliding rail system to move the blocks around and up?

Peter,  the amount of hands on experimentation, great photos,  excellent drawings and clear documentation you have share here calls for a book!

I second the motion!
After all, with the break from building and all that free time you must now have on your hands (when their not busy feeding your rmh or petting your girls) what a great way to pass on your fountain of knowledge.

...can you tell we miss your updates Peter?  

If you are worried about insects, try boiling the rice husks in a solution of borax and copper sulfate.  Borax, at least in the USA, is readily available in the laundry section of most larger markets.  Copper Sulfate is readily available from farm stores as an algae control for ponds.  Since you are in Japan, YMMV on where to find these compounds.

You won't want to breathe the vapor but it should convert to Copper Borate at about 50C to 60C depending on your elevation.  Copper Borate is used to treat most pressure treated lumber.  Since you have to wet them to make the concrete anyway, the copper and boron will be heavily antimicrobial as well as stopping rot, adding some fire proofing, and providing insect resistance.

Gerry Parent wrote:I second the motion!
After all, with the break from building and all that free time you must now have on your hands (when their not busy feeding your rmh or petting your girls) what a great way to pass on your fountain of knowledge.

...can you tell we miss your updates Peter?  

I know!

Thanks so much for reaching out. It’s been a bit of a struggle for me the past few months. House is definitely on hold for the time being. Begin to think of just abandoning the project all together to be honest. Finding it more and more difficult to justify trying to spend all my time and creative energy trying to devise a means of staying warm in a cold place.

Simplest solution, move to a warmer place.

That I’m sure will have it’s own kettle of fish for sure, but we will see.

I truest do appreciate all the support and have been meaning to update.

We will keep searching and exploring.

Hope everyone is safe and smiling.

Cheers, Peter

I hear ya Pete! Living in the Great White North of Canada has the same cold, snowy issues.  
For me, this forum makes the world seem a little smaller which helps me to see beyond the bleakness of the long winter months.
Whatever way you choose to go, stay in touch.

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You folks have really been such an amazing inspiration us.

Will keep you posted.

Forever in debt...

Peter & Co. 🙏🏽

What happening now, I am intrigued?

i love stories like this, please keep sending more information and pictures

Four years after the fact... I happened across a Youtube video that mentioned carbonized rice hull being used as underfloor insulation in a Japanese house build, so it sent me down this rabbit hole.  I'm in Texas, myself, so quite different climate conditions, but I'm wondering if you could provide any pointers or pros/cons from your own experience using it.  Looking for further information about using either rice hulls or carbonized rice hulls as insulation, as a DIYer, this thread was the only real lead I could find.

How did your loose fill rice hull insulation end up working out? Or the ricecrete? Did you use straight hulls or carbonize the hulls for either usage?  Did you add borax, or have any trouble with insects inhabiting the rice hulls? How was the performance of the insulation, overall? Mold problems?

Just hoping for some updates on this technique, if you happen to see it!
Thanks.