STEP 3: Plumbing - sewage

Ok, plumbing was a whole new chapter for me - I will share what I learned, but remember by no means do I have the plumbing wisdom here - just this experience.  The only plumbing I created for the foundation was the drain pipes and vents for the sewage system. Since I will not be burying my dome and will have venting windows and doors in the structure, I did not provide for any extra vents in the foundation floor, something you would really want to think about when you berm or bury your structure.

Plumbing

I decided to have my water lines, electrical and propane enter the side of the dome, so they would be easily accessible for repair or changes, plus I didn't want the headache of figuring this out in the foundation - so it bought me time to focus on these aspects later.

In order to make sure I did my measurement correctly, I got my toilet (craigslist but new), bath and sink (VJ's in Rochester) and bathroom sink (a gift) ahead of time and placed them inside my future dome, making calculations for the thickness of the wall between the bathroom and the kitchen and shuffling thing around until I found their right spot. Then I decided how I wanted to connect these pipes. I decide to separate the gray water (sinks and bath) from the black water pipe (toilet) after it was informed this is the proper way to go, it also made sense to me for the future in case I wanted to separate these drains and their 'treatment'. The pipes for grey water I was told are 2" and the black water pipes generally 3", so I got those.

I was informed that the toilet also needs something called a toilet flange. Off course in order for the pipes to drain properly they need to be under a certain slope/angle. They rule of thumb that I got is at least 1/8" drop per 1 foot of pipe, or in other words approx 1" per 8 foot of pipe. Also, it is said not to make the drop too steep, since liquids will flow, but solids will drop and not flow with the liquids. If anyone had more info, please feel free to add to this knowledge!

Ok, another point that I find important to share is that the pipes need to be flush with the concrete floor once it is being poured, so use a level on a board (or if you got a laser even better) to make sure it is exactly that because if it sticks out you will have a hard time leveling the concrete floor around it and in case of the toilet and other drains like a shower or a bath that need to be connected at floor level, it is essential that they do not stick out above the concrete floor. Anyway, something else I remembered is that you can use duct tape to cover all the drains and an extra piece of carton board between the flange's moveable part and the concrete so it will not be stuck to the concrete and you will not be able to move the upper ring into the right position.

One more thing about the sewage pipes is that you need to use a coupler at the end of every pipe (flush with the floor) to make sure you can fit another pipe in there after the floor is poured to connect to say your sink. If you cut the pipe and make it flush with the concrete floor, you will have nothing to work with and build upon once the floor is done. Very important!!;) that would suck...

STEP 2: Foundation Ring

For my foundation I have chosen to work on a level spot and build the foundation up from there. Off course you can also dig into the ground and make your footer level with your ground. I opted for placing my footer on top of my leveled earth and will need to provide for some step to step into the dome later. The dimensions I worked with are as follows:

radius: 20'

radius + concrete thickness = 20' + 12" = 21'

footer ring boards are made out of 1/2" plywood boards with a 12" height

the center 19' circle is filled up with 6 yards of washed sand to create a 6" surface from the top of the footer ring boards.

Important: in order to make the boards for the footer perfectly level, you need to start with a reference stake in the center that is at exactly 12" and keep making sure that the boards are level and on 12". We actually used a laser for this and it was wonderful and fast way to work. My original idea was to use a long flat board of about 12' to lay on top of the center stake and the footer boards and use a level on top of the board to do the measurement. Luckily I never had to test that idea, but I think it should work if you can't get a hold of a laser.

Center is chosen and I have drawn a circle from the center of the dome to the outer edge of the foundation, which is 10' (radius) plus 6'' for the thickness of the concrete that I have chosen at the bottom of the dome. The dome will be sprayed later with the concrete mixture on average 4" thick, but the bottom will always be thicker than the top because it takes the most amount of weight, so I allowed in my foundation for 6" of concrete. Just outside this line is where the form boards made out of plywood will be placed, which are 1/2" thick and then the stakes are behind the boards to hold them up. The 90 degree green angle that I have drawn in the circle represents the area for the bathroom.

I bought 3 half inch plywood shop grade and had Home Depot cut them into 4 pieces of 12" by 8 ft. As it turn out you loose some of the board by cutting it so only 3 out of 4 boards where the exact measurement that I needed for the footer ring. And 8.5 of those boards was enough to make the circumference of the footer ring. In order to 'pre-bend' them - so they would not break when we were bending them into the work area of the footer ring, I placed them on my saw horses with some weights on them and watered them regularly.

saw horses, a skill saw and a screw driver are needed for this phase, as well as a hammer to hammer in the stakes. The screws needed for both attaching the boards to the stakes and the boards to each other need to be longer than just the thickness of the two materials, to give the connection extra strenght.

stakes are set at 2' distance. Nail them in deep enough so they are solid, however they need to be sticking out enough to support the boards. I worked with 18" stakes, and it was just about right, however if your soil is less hard than mine, you might need to go deeper. These stakes come in all sizes up from this, so pick the one best for you by buying one and testing it out on your surface. I was also advised to make my own stakes with 2 x 4 beams and that would have been a lot cheaper, however with my hard and rocky soil there was no way to get them in there deep enough to grab onto the boards and hold them properly.

boards are connected and then drilled into the stakes that have special holes for this purpose. Be aware while placing the stakes that the holes face forward towards the boards for easy connection ;)

the boards need to be connected with lots of screws, I think we used about 12 per connection, that are a bit longer than the 2 boards that are being connected for optimum strenght- you have to realize that a lot of pressure will be pushing against these boards once the concrete is being poured into the ring.

the ring is complete and level - we had the grace of working with a laser to make sure all was level - I am not sure of other methods - but this was awesome and fast.

STEP 1: Preparing the spot

STEP 1 in this building process was preparing my building spot. Talking to several excavator guys, I discovered that if you want to berm a home/dome/house it is much more cost and labor efficient to move the dirt once instead of twice. In other words, place your dome(s) where you want them and then bring the dirt to the domes.......instead of choosing a hillside and moving the dirt twice - seems simple enough, but that somehow did not occur to me.

My decision of where to place the dome and how many I wanted was easily made on my property since the top of my property is flat and the rest of the 5.5 acres is mostly hillside and forested. However, I discovered that in order to place my domes in a most optimal way, I would need to clear out more trees on my plateau and get some excavation done to remove and level my ground. During this process, I was also busy drawing my domes, their position relative to each other, the connection hallway, the mudroom into the first dome, the other door and windows etc etc, soon enough I was drawing in detail the layout of the domes and their surrounding landscape that had to provide for some parking, dog area, garden, driveway to the shed, porch area - covered and open. An easy way to draw the dimensions in accuracy is an good old notebook with a grid, however there is a lot of floor plan software out there on the internet you might enjoy, some of them free.

Here is my land after the removal of some trees and leveling my spot.

I figured since I knew the dimensions I could work with and I had decided I wanted to create two domes that were connected with a hallway, I should detail my plans as much as possible, because the step right after leveling is preparing the foundation ring and in order to do that properly, you will at least need to know where all plumbing needs to be and where you will be placing the doors. I figured that since concrete is very 'unforgiving' with the location of anything - you better know for sure where you want your toilet, bath/shower, sinks etc - and to make sure that I gave everything the correct dimensions I decided to purchase my doors, bath, toilet and sinks, so I would know exactly how they fitted into my dome and where. Anyway, I am getting ahead of myself, I will get into the plumbing part later.

INTRO: 'I am green...'

I am green. I mean that next to my aspirations to build sustainable and self sufficient, when I started this project my greenness mostly revers to my lack of building experience.

My habitat before the Hobbit Dome was my 30 ft Yurt, and putting that up was certainly an experience, however I was mostly the one that handed the building stuff and got supplies. A Yurt is also a real easy construction without many nails, screws or moving parts, except for the deck and finishing the inside. Anyway, I loved the Yurt, mostly because of its round shape and skylight and when I was thinking of a more sustainable, better insulated and perhaps safer structure I was mostly attracted to a dome shaped building. I ended up buying into an Eco Shell Air Form (www.monolithic.com) with 4 friends, which can be reused several times (even up to 100 times they say, if you care for it very well), so everyone could build one or multiple domes with this single investment in an air form. We bought a used one at $2000 with a 20ft diameter. The Ecoshell was originally created to make low cost and safe building possible in developing countries. See a picture of a 20 footer under construction below.

Ok, what is an air form you might ask and how does it work? Well, short and simple, you can blow up the air form and than apply concrete and reinforcement to the outside and Voila - you got yourself a dome. When all is dry you can take the air form out and reuse it. Off course at closer examination there is much more to it and I would like to share my journey as I am making it, so anyone with the same or similar dream, might be inspired and can learn from my experiences and discoveries. I will make pictures at every step and will endeavor to post regularly, so my story is in the moment and fresh from my mind to paper.