Planing a new Tiny house cabin in a slope terrain [Sketch model and Foundation brainstorm]

Hi all, we are back, almost 10 years since the start of our first Roundwood tiny house and we have a new similar project in our heads.

Our first house was built on a EXTREMELY low budget (was meant has a temporary laboratory house, made on top of a SQUATTED ruin) with free local, ecological, repurposed or second hand materials and a few cheap material. This next project will be on a small piece of land we bought very cheap just near the terrain of some friends and a "forest" (tree plantations).

The plot is a sloped strip of land that ends on a small stream that flows all year around. (slopeTerrain.png - not in scale according to the terrain i must clear a bit the bushes and take some better measurements on the angle of the slope)



Material available:
- clay/clayish ground
- sand (from the stream)
- pebbles (from the stream)
- stones (rounded stones from the stream and some other from the land)
- Roundwood (Eucalyptus Globulus and Acacia Dealbata - two invasive species)

The plan for now is to build a small two floor tiny house similar to the one we did before (video below) but without the basement, there is already another building for the brewery



For now we imagine digging the slope by hand (hopefully with the help of a couple of friends) to have a flat surface to build and collect materials.

we started a small sketch to start visualizing it a bit (check attachments).

After digging the slope i imagine starting the foundation (House building focusing on Good boots and a good hat philosophy).



Thinking about making Rubble Trench Foundations, there is no freezing in this area but a lot of rainfall (>1200mm/year), so i think digging half a meter deep would be sufficient, then setting a French Drain (pipe with holes) and filling it with stones, pebbles and sand from the river, then building a bit with stone and the rest with (roundwood) timberframing.

We would like to be discreet on the landscape so we were still wondering about making a living green roof or not.

Still also open to brainstorm ideas for the floor of the ground floor, should it be in wood with a air box underneath? direct on clay? maybe rocket mass heated floor in the future?

let's see how it goes, will try to keep this updated but is still just a plan in the air, we need to be more time on the terrain clearing and making measuments to continue.

I enjoyed seeing the progress of your previous build. It will be interesting to follow what you do on this site.

On the general layout in your sketch, I would make the shed roof that heads back to the hillside warp or be sloped or have a gutter so that it sheds rain off to the sides rather than straight back into the hill. A gently sloped retaining wall of the round river rocks supporting the end of the roof would make sense. This would make a nice cool shaded patio area for summer afternoons. I would advise having the foot of that retaining wall lower than floor level so that water would positively be diverted away from the rubble trench footing.

A green roof needs to be close to flat (< 1:12) or else have structural bracing to keep soil from sliding down, so you could keep that in mind in your planning. It is possible to have a real slope on a green roof, but definitely more complicated than a nearly flat one.

Just looking at that pic, I like the design and you mention some what sounds good to me drainage to work with the design, proper gutters and downspouts can likely make about any roof suit the bill.

The only thing Id consider is make more room behind the house (taller wall) for more useable space under roof. Although the Earth mass back there has its climate control and protection qualities if left (or possibly even make a root cellar/storm shelter area of sorts).

Wow J, your spot sounds like a real slice of heaven.  I like your ideas and your sketch, I believe Glenn about the slope creating potential problems however.  One remedy I have seen was the use of peat and materials like vermiculite in large proportions in the soil.  That allowed much of the rainfall to drain quite rapidly,  and plants like strawberries seemed to do well on that roof. The light weight soil  lessened the tendency to slide , I was told.  

One last suggestion for this Basqu bungalow: would you consider borrowing an idea or two from Mike Oehler? Here on this very forum is a video illustrating his uphill patio , it allows amazing sunlight and still deals with drainage issues. If you like his method, living roof access could be via ladder/stairs maybe?

Cannot wait to see this abode come together, you have an exemplary start!
Rico

Thanks for the feedback already

Glenn, I was thinking of a green roof just off my head, not really investigating further, nice that you mention that 1:12 roof slope for green roof (i assume is losing a meter height for every 12 meters long) i changed my sketch and noticed 1:12 is almost flat and would not be able to join to the ground of the slope.

really appreciated the comment on a good footing for the retaining wall of the hill

"A gently sloped retaining wall of the round river rocks supporting the end of the roof would make sense. This would make a nice cool shaded patio area for summer afternoons. I would advise having the foot of that retaining wall lower than floor level so that water would positively be diverted away from the rubble trench footing. "

Cole, I'm really enjoying the size and design of our current house that was depending on the size of the original ruin, next one there is no original foundations so there is space to change a bit, but we would keep the separation from main room/kitchen floor and a sleeping room smaller and upstairs. after starting drawing it with the long back roof i also though of using it as a small workshop, for tools and bicycle, but what did you mean about the taller wall behind the house? not sure if i got it.

Rico, yeah,  i see now that a green roof is probably not the best option if we follow that design like glenn said, i would not try to go ahead with a different angle and then fail...better to jut use other kind of roofing or changing the  design, i've seen  Mike Oehler underground house before, i like the idea but i guess not the best for my climate, a lot of humidty i would be afraid of molds and dampness, one of the reasons to build a bit up and have the room upstairs, but i will definitely investigate this option further

playing with the sketck a bit more we also thought on bringing down th second floor for a room and just make two rooms on the ground level...which would maybe iplicate more digging, but if we already already were thinking of a space behind the house the digging is similar

J. Tabordiy wrote:playing with the sketck a bit more we also thought on bringing down th second floor for a room and just make two rooms on the ground level...which would maybe iplicate more digging, but if we already already were thinking of a space behind the house the digging is similar

I happened to re-watch Mike's video on the Kirsten Dirksen channel today and he said something that I think pertains to this design; which is that in his opinion, a design like this where it directs the water all at the back wall of the house is not ideal. Ideally you'd rotate the house around 180 degrees so the slope of the roof matches the slope of the hill (rather than making a v shape in the middle).

BTW, is this sketchup you're using? Just curious because I was thinking about making some sketches today and wondering if that's still the best free program to use.

Conrad Gozen wrote:

I happened to re-watch Mike's video on the Kirsten Dirksen channel today and he said something that I think pertains to this design; which is that in his opinion, a design like this where it directs the water all at the back wall of the house is not ideal. Ideally you'd rotate the house around 180 degrees so the slope of the roof matches the slope of the hill (rather than making a v shape in the middle).

interesting, can yo point out the video?
but it makes sense, i guess i was more thinking on sun direction but i might be a problem to have the roof pointing "in" the slope...

the project is on hiatus, so next time we start thinking about it i will take that info on thanks

Conrad Gozen wrote:
BTW, is this sketchup you're using? Just curious because I was thinking about making some sketches today and wondering if that's still the best free program to use.

yes, i dont use that often but find it very easy for sketching 3d... in linux i used to run an old version otherwise would crash, but lately the online app works great: https://app.sketchup.com/app

Can the roof be designed purely for the benefit of the sun into the house.
Drainage and soil walls can be dealt with separately.
Have you considered an underground house facing the stream?
Will you capture rainfall for use in the house?

I'm with Conrad here.
Chapter 30 of the Building a Better World Book also deals with a house in a slope, especially pages 244-250.

Some things you could read up on here are "Wofati" and Mike Oehler.

Jeremy pointed me to the richsoil article about Wofati. That would be a good read

I was also thinking "why is the slope of the house opposite of the hill". Entry of Sun sounds like a good reason, but for the water it is not handy. Gutters sounds nice, but what happens in the case of a 10 or 100 year event? At this moment we have been in a 2 month long storm with a lot of water. The stone walls and roof have been saturated with water for at least a month and water is appearing in many unwanted places. You never know when such an event strikes, because this is our second winter here. I would thing very hard about this for your house. Your water system should be design for the 10 or 100 year event, else your entire house might be destroyed. In this case, with the questions about foundation, maybe making the house off the floor with wooden beams sitting on (very) big stones. Maybe with enough height of the house, you could even plant something like vetiver underneath the house to hold everything together when there is water racing of the slope.

What would be the reason to connect the roof to the slope? Collecting all the water of the roof would make it more accesible for storage and use.