Just found this forum and pretty excited to find a community of owner-builders

I'm attempting to build a tiny house for my partner and myself to live in on our urban San Francisco Bay Area backyard. I've been doing my best to learn as I go from the internet and the library but by all means I welcome your advice and input


I've started the foundation but have doddled for months now. I originally was going to go slab on grade but I wanted an insulated slab and I don't trust foam for structural strength so I switched to a three stage pour (footer, stem wall, slab). Poured the footer and have built the form for the wall, going to do the next pour soon. Ugh, concrete

This is the framing sketch thus far



No frills really, simple. I would like it to be a "green roof" (or vegetated roof) which might be complex, we'll see.
Small kitchen with two burner stove and under counter fridge. The sinks and shower will be greywater and there will be a compost toilet. Loft for sleeping





Milestones thus far:

Laying rebar in footer trench


Pouring footer with vertical tie-in rebar exposed


Wood form built for stem wall

(mascot bbq snuck in)



I have my plan for where the anchor bolts are going, have all the materials, just have to pour

   Looking good!   Excellent floor plan . . .    Good use of space.

/.

My brother build a similar house (bit bigger) in a local city (binghamton) and it generates a lot of attention.  I love seeing the country influence the cities for a change lol.  BTW his assesment is so low he pays no school taxes and not much land.  If you choose to do a green roof I def watch and learn with ya   I am not sure your framing (2x6s 16 on center).  but just make sure it can take the added weight, if you need figures I am sure someone with good knowledge will help you size it out on here.


Looks great thanks for taking the time to share it with us    Your house will no doubt give you a great deal of freedom in life.

 

Quotepartner and myself to live in on our urban San Francisco Bay Area backyard

whats in the front (and mid?) yard?

Thanks gents

Its a 4000sq ft lot with a 1500sq ft 1919 home on it that I already own. I currently live in the house with some housemates but would like a space of my own and increase my income a bit.

Im not 100% on all the framing choices of course. I did some back of the napkin calculations and came up with 2x6@16. I estimated the load of the vegetation to be just slightly greater than asphalt shingle, around 17-20psf dead, 30 live (after rain) (3-4" lightweight growing medium, some sort of lightweight drainage plane Ive yet to come up with and an EPDM liner). No drywall or plaster on the ceiling.
I want to do roof decking instead of OSB or plywood but not sure what thickness I need. I have a free supply of 3/4" rough oak planks from pallets that Id like to use

Costs so far:

Concrete, purchase #1 (footing), 50 80lb bags   $176.31
Rebar 20ft and ties, HD   $36.77
Rebar, CL   $0.00
Welded wire mesh, CL   $0.00
Vapor barrier, PET sheet, estate sale   $2.00
Lumber run #1, concrete form->studs   $95.46
Concrete purchase #2 (stem wall), 17 60lb bags   $49.82
Concrete purchase #3 (stem wall), 25 60lb bags   $66.75
Anchor bolts and washers   $8.97
Window, kitchen, Freecycle   $0.00
Window, loft, ReStore   $30.00
Door, ReUse people   $123.47
Faucet, kitchen, eBay   $26.00
Compost toilet, CL   $300.00

$839.83

Items made from pallet wood are likely to be durable and demonstrate good weather resistance due to these treatments. However, close contact with pallet wood or inhalation of dusts from sanding or sawing can be a source of exposure to pesticide and fungicide chemicals. It is likely that the January, 2010 recall of Johnson and Johnson Tylenol[TM] and other drugs were due to their being stored on wooden pallets that had been treated with the fungicide/pesticide 2,4,6-tribomophenol. This chemical can be degraded by molds to produce 2,4,6-tribomoanisole whose strong, musty odor caused consumers to complain.[34] There is no acute or chronic health data on 2,4,6-tribomoanisole,[35] but it is believed that the contaminated drugs caused nausea and other health effects in some people.

Finally poured the stem wall. Man I hate working with concrete. Stressful having that ticking time bomb
Unfortunately since Im a total amateur I had a lot of honeycombing Ill have to patch over but hey, at least its done

Just curious, but do you have to do anything special in case on earthquakes? Like shear wall, or something like that, or is this too small a footprint to worry about that?

Earthquake damage is a serious concern and I'm trying to take every step I can to be safe

The structure will be sheathed with 1/2" CDX and that will add the shear strength necessary. Beyond that, I'm just going to make sure that everything is properly tied together (roof to wall, wall to foundation, etc)

Well, progress continues! Finished pouring the floor slab



6mil poly, 1.5" rigid foam, 6" welded wire mesh. Foam is placed around the edges with a 45 degree bevel for complete isolation from the ground. The house will be passively solar heated in the winter and this should go a long way to keep the floor warm



We chose to do an earthen floor with 1/15th cement. The clay/silt/sand and urbanite aggregate was from on site. The bottom layer is an aggregate rich mix while the top is fines mixed with red powder pigment; this will be the finished floor



End result is pretty good. Has a bit of "character" for sure. Going to take a good while to dry and have the color even out.


Next, framing!

The earthen floor looks really nice.  I like the color a lot. 

Since it's allready done , there might be no point in mentioning it besides others whom might read.  It looks like the insulation you put down is polyISO.  I don not know of any styrofoam that has a reflective surface.  Poly Iso does not work below grade because it absorbs moisture more the sytrofoam (usually pink or blue in color).  I would think even the poly you used should help a bit anyway b/c I doubt the cells will fill completely with moisture?  If for some reason you feel you are losing heat through the floor you could always add 2 foot of "wing" insulation (Blue board or pink board ran out almost horizontally, with a bit of pitch going away from your frost wall)  This could be done any time after.

jeff

Thanks! We winged it with the pigment, just randomly chose a ratio


I was concerned with whether this foam board was suitable for below grade applications so I consulted with the company and they claim that its suitable. Their FAQ: http://www.rmaxinc.com/faq.asp
We'll see though!

sounds like you did your homework then.  Sometimes you hear things over and over and unless someone actually tests who knows.  I know that I have left poly iso out in the elements and although it gained a bit of weight from mositure, it was not saturated.  It will be tough to ever know .  I doubt you will digging up your floor to find out lol.

I heard some cities were going to allow this.  Were there any restrictions or are you just doing it?  Seems I missed that.  Thanks.

The earthen floor will be quite soft and easily damaged we have found out.  Though it would darken it a lot, several coats of boiled linseed oil would increase durability.  Possibly water base polyurethane would work and leave the lighter color.

120sq ft buildings don't require a permit but are not intended to be habitable or have plumbing or electrical. For all intents and purposes, we're building a "shed" 

I have a liter of mineral oil lying around that I'm going to test as floor coat. Should work just as well as linseed oil Id presume. Will do a couple coats

In the UK we have lots of lime and sand cement and earthen based plaster

we use PVA adhesive as a sealer as it mix's with water and penetrates into the plaster

Its not tough enough for a finish but does hold loose grainy materials together so that you can apply other coatings on top

http://www.amazon.co.uk/Unibond-Super-Adhesive-Sealer-Primer/dp/B000Y8L9RG

Is the major brand name - many others are available

I use it in the garage to keep the dust down liberally splash everywhere and brush arround....no dust till next year

One thing I've found when there is cement in the earth mixture - it takes a lot longer to soak in & if applied too think will be sticky for quite awhile.  If you end up using boiled linseed oil, thin it w/turpentine - it will soak in & dry faster.  

It does darken the earth floor quite a bit.  I've put several layers on the stairs leading to the top of the uphill patio - I coat it at least once a year.  I've also put it on the dirt ground at the top.  It has hardened the floor & really increased the durability.  The stairs used to chip off on the edges so I had to repair them several times.  

You may have read about the floor in the front porch - that hardened like a linoleum/rock floor - no cement, just several coats of linseed oil that Glenn applied once the floor had dried.  If it wasn't for the bull pine roots growing under it having cracked it in an area, it would still be in perfect shape, nothing else seems to bother it.  

That reminds me,    I think it's due for another coat  

I'm just curious - why build a small home if you already have a home next to it?

Nice work on the foundation by the way.

Thanks

We have a small community of people living here as a co-op in the main house and will be 8 people total once the tiny house is done. We're trying to generate more income for us and our projects, provide sorely needed affordable housing and foster a like minded community of people working together

tinybackyardhouse
You are making great progress.
A lean-to style like yours is very forgiving, and a nice, simple, strong structure.
Hope you are enjoying the adventure.
Oh, the excruciating fun.
Please savor it all.

I build models before I get out the hammer...and wallet.
One of our considerations was this style (196sf) and room for a loft.
There's a name for it, but it escapes me.

Wahoo! Framing is well on its way



Feels good to finally see what has only been a digital representation now turn into a tangible visible accomplishment.
Mental note for the future: buy kiln dried wood!

Looking good     Did you use Google Sketch up to make the early drawings?

Yep, used SketchUp the whole way. Been a great tool although it is helpful to step back and realize that the real world is NOT a perfect computer model where everything is square and every board is straight


EDIT:
Cost update thus far: $1070.70

Some more progress



Walls are all plumb now and most of the sheathing is on. 2x6 rafters are up with Simpson seismic ties.

Ordered an EPDM pond liner for the green roof. Clock is ticking, winter rains will start eventually, just hope I can finish in time (I'm seriously slow at this)

Well didn't make it before the rain but better late than never, finally got a waterproof roof
7/16 OSB with 2" rigid foam. Made a last minute decision to add a 14x56 skylight. Used heap 1x8 redwood fence boards to hold in the soil on the roof.




Decied on a soil mix of 1/3 compost, 1/3 perlite an 1/3 coconut coir. I calculated I needed about 60 cu ft total. The compost I can get for free from the city but the coconut coir and perlite set me back $125. I weighed the mix to make sure it was within spec and a wet 4 inch layer weighs in at 6.3 lb/sq ft; well within range



Next up is getting tar paper on the walls. She is going to fare a lot better in the rain now though


Cost total so far: $1,727.42