A point of reference

We're comfortable in our current house, although a few small changes would make it much nicer. To give us a point of reference, I drew the floor plan in SketchUp. I present it to you here:

1287 sq. ft. on the books.

The house was built as a rectangle, and then had two additions.

First the dining area was added to the kitchen. It's nice, with 3 large windows looking out at the neighborhood, although the temperature swings are wild. The East end of the large living room was originally the eating area. For us it's a kids' play area.

Later the bedroom on the North side was added. The hallway to that room was taken out of the bedroom on the West side, as was a small hall closet. The hallway takes 60 sq. ft. but offers very little in return.

I don't know when it was built, but there's a tiny water closet in the North bedroom. Toilet only, no sink. I imagine the original owner, a G.I. who had this house built as he started a family in 1950, had a hard time making the trip to the bathroom at night, 50 years later, so he had that toilet added. It belongs to our cats today.

There is forced air heat in the original bedrooms, bathroom, and living room. The North bedroom has baseboard electric heat, which stops us from putting furniture in useful places. The dining room has baseboard heat that we never turn on, because we're only in there for a short time each day, and because the floor is uninsulated, so it would be lost quickly.  The kitchen is unheated, but when we're cooking it's not bad.

A big complaint I have here is that there's nowhere in the laundry space to leave a basket of laundry. It only needs another 10 sq. ft. to be so much nicer.

While I'm at it, there is a cold air return in the floor in a high-traffic area. It hurts to walk on barefoot, and the kids' toes get caught sometime - very painful. Also, the hardwood floor finish is in very bad shape.

Our landlord offered to sell us this house, but it's more than we wanted to spend, and refinishing the floors would mean moving out entirely anyway, so what's the point?

Anyway, there's a point of reference for ya.

The "ferry" sketch

I was riding on the ferry to Keystone and came up with an idea that led to this floorplan sketch.

It has a lot of the same features as the  previous floorplan. The main difference vs. is that the wet wall is not straight; it's U-shaped. There's a bathroom on either side, and the kitchen sink would be to the south. Plumbing distances are even shorter. That leaves a much smaller utility room on the north side, instead of a huge attached garage I had before. That makes the structure a bit smaller, making construction more doable for this amateur.

The house less square, which is good for solar gain (more insolation on the South) and good for getting light in to the kitchen (previously the kitchen was much further from the windows).

It could better fit a shed roof, which might be good. A shed roof here could come down very low on the North, even to 6' high, as bedrooms and bathrooms can tolerate a low ceiling, while being quite tall (hopefully elegant) in the daytime spaces. (In the past I've lived in rooms with low sloping ceilings and hated it, but 6' should be OK.)

Square is better for central radiant heat (round is even better). Square also requires less exterior wall building for a given square footage (round is again better). So that's a compromise.

It optimizes for sunlight in the daytime spaces more than the sleeping spaces.

Note the alcove entering the rooms (possible bedrooms) on the East side, creating a transition from public to private space. The Northwest bedroom still needs that.

More to ponder...

Utility room

Many of the house floorplans I play with include an unheated utility area. The interior walls of this area are insulated. My understanding is that its square footage doesn't count for taxes or for the 1250 sq. ft. maximum ADU size.  Also, having a cool space like that right next to the kitchen is great for food storage and fermentation.

Additionally, I usually put all the plumbing in its walls, so I don't have to plumb in exterior cordwood walls.  This will make it much easier to repair and modify plumbing over time, which otherwise is a pain in the neck.

Sometimes I think this room will also be a mud room / airlock, used as the primary entrance by the people who live in the house.

I brainstormed a list of things I could put in that space that don't need to be in heated space.

• work sink
• domestic hot water heater
• boiler for radiant floor
• washer & dryer
• table to fold clothes
• recycling bins
• litter box
• server & wiring closet
• shoes & jackets

I also thought of stuff that we currently store inside the house or in the garage that would be better stored in this kind of space.

• spare rugs
• sofa cover
• off-season clothes
• art supplies
• files
• photos in boxes
• food (canned, fermented, dry)
• idle toys
• sewing machine
• spare litter
• soaps, shampoos, and other cleaning products
• broom, mop, bucket
• spare computer parts
• spare light bulbs
• vacuum cleaner
• basic toolset
• toilet paper
• sawdust for composting toilets
• laundry waiting to be washed or folded
• ironing board

The growing house

What if you don't want to build too big, but lots of small houses are too small? Another option is to build a small house that grows in time.

For example, a kitchen with an open space. At first you sleep in the open space and eat standing up. Then you add an addition with a couple sleeping rooms, and the open space becomes the dining area and social space. Maybe you add a den.

It has many of the advantages of the small houses approach, without requiring nearly as many walls. You have to get a lot of the planning right up front, though, or you end up with a very awkward layout. You also end up with huge exterior walls taking up interior square footage.

I think that an addition has to big enough to justify good construction. A tiny add-on space won't be worth the time, materials, and money of good insulation and foundation.

I suspect that we'll build the house in one go, but there are a few add-ons that might make sense.

An attached greenhouse is interesting. It can extend the growing season and sprout seeds. It can capture solar energy to heat the house more. It can act as an airlock to the main entrance of the house. It sounds nice to enter the house through greenery, year-round.

I'm toying with the idea of making the the greenhouse be a sitting room / enclosed porch, too. Somewhere that adults go to socialize or read. TV-watching and kids toys are in a different room, which could eventually become the 3rd bedroom. Not sure where this goes, just pondering it right now.

Build a collection of houses

One option I thought about for a while was to build a bunch of tiny buildings. For example:

• A kitchen, eating space.
• A shower, sink, toilet, drying chair, washer, dryer.
• Bed for parents.
• Beds for kids.
• Play space for kids.
• TV and sofa.
• Study.
• Workshop.
• Sauna.

Each could have a composting toilet and foot-pump handwashing station in the corner with a wall or curtain.

It would be easy to build the most important ones, move in, and then add more over time to match our ongoing needs. Some could be arranged in a circle, close together, making an "outdoor room" in between. Some could be nestled off in the woods on their own, for solitude. Framing and foundations get simple for small buildings. If we don't build the right thing, it's not a big deal. It's easier to be resourceful and thrifty on the small scale. If you don't have savings, you can get started without taking a loan, and grow as money allows. Many of the small buildings won't count as dwelling space for taxing. You can live in a finished space while working on the next one, instead of living in a house under construction.

I could experiment with different styles: One could be in the best sun spot, with solar panels on the roof. One could be round. One could have a living roof. 

We can even tear down one if it's really wrong without losing much.

However, there are some reasons not to do this:

Each one needs its own heating infrastructure. If there's a lot of thermal mass, then heating one up for just 1/2 an hour doesn't make sense. To get all the space of a full-sized house I'd need to build a whole lot of exterior walls, which means lots of materials, time, and money. Walking outside every time you go between rooms in the middle of winter is unpleasant. In the end, they'll take up much more space on the land. We're already a family of 5, not a couple getting ready to start a family. 

For now, we've tabled this idea. (In the U.S., to "table" means to set aside, to reject for a time; in the U.K. it means to open a discussion. I mean the first one.)

However, I'm still considering a full house with some outbuildings to be added over time.

House size

I've read the advice that an amateur owner-builder should build small.

I am trying to design a house that stays under the 1250 sq. ft. threshold, because the law would allow me (or someone who buys this land later) to add a new, larger house to the property, and count the small house as an "ADU" (Additional Dwelling Unit, to be rented out).

1250 sq. ft. is not unreasonable for us, even as a family of 5. 2400 sq. ft. is the average for new homes in the U.S, wow!

The house we're renting is 1287 sq. ft., and we're comfortable. I wish there was another 10 sq. ft. around the laundry, and an actual second bathroom with sink. But there's also a long hallway that wastes about 60 sq. ft. and the back bedroom is way larger than we need. This house is not well-insulated, but the one I build will be, with thick cordwood wall, probably 16" thick. The county measures external square footage, which discourages insulation (I could get R-35 with 24" walls, like they use in Manitoba) but I won't make the 1250 threshold, and I will be taxed more. (That way of measuring makes sense when you consider the effect of a house footprint on a neighborhood.)

So, 1250 is doable without giving up much.  Could we go smaller? Many, many people live in much less space.

We make good use of all the rooms in this house. One bedroom doubles as my study. Another as Julie's. Another is where Reid goes to play by himself. I don't like how we split up in to singles like that, and the fact that we spend most of each day indoors in front of screens. I hope that when we are living in a house in the beautiful woods, growing much of our own food, we will want to spend much more time outside. For now though, I need to use this computer just to figure out how we're going to get there.

I also know we can add outbuildings. Anything under 120 sq. ft. can go up without a permit, so I could add a couple of those as needed. Like a study where I can really get away from everyone to do work for money. Or a sauna!

An attempt at a footing

I was reading about footings and foundation walls, and tried to imagine how those might look in this house.

The purpose of a footing is to distribute the weight of the house so that it doesn't sink in to the ground ("settling"). Settling causes cracks in foundations, in drywall especially around openings, and doors that stick.

I would like this house to last for a long, long time, so getting the footing right is important.

A rule of thumb I've often read is to make the thickness of the footing equal to the width of the wall, and twice as   wide at is it thick.  A common insulated cordwood wall thickness is 16" (4" mortar, 8" insulation, 4" mortar). In Manitoba they build cordwood walls at 24" thick (4" mortar on either side, and 16" insulation, wow!). I want an energy-efficient house, but I need to balance that against how much wood I have, how heavy the cordwood logs will be, how much concrete goes in to the foundation, how much excavation the footing requires, and the fact that wall thickness is included in the official square footage for tax purposes. (Stupid, why charge people for good insulation? It incentivizes the wrong behavior.)  A 16" cordwood wall is about R-20, which is a common code requirement (although a well-built 16" cordwood wall will far outperform an R-20 conventional studded wall, because the studs transmit heat but are typically ignored in the calculations.)

Anyway...

A 16" x 32" footing, over the perimeter of a 40' x 40' structure requires about 21 (cubic) yards of concrete. At $75/yd, it's $1600.  That's just for the concrete, not for excavating or installing forms or anything else.  I plan to have a concrete slab subfloor, as well.  If you assume 4" thick, that's another 20 yards, or $1500 more. It's adding up, and we're not off the ground.

I like the slab for its high thermal mass for solar gain and comfort. It's also good for radiant floor heat, which is supposed to be very comfortable. I also don't have to build a crawlspace, so it keeps things simpler.  (Unfortunately, the systems you might put in a crawlspace, like waste plumbing, have to be built in to the slab, so that's a bit of work.)

If I'm going to all the trouble of pouring 21 yards of concrete in a footing, I'd like to take advantage of it for thermal mass. That means insulating the outside of the footing. I'll actually put Dow Styrofoam Blueboard panels down before pouring the footings.

In many places, the footings need to be deep, to protect against frost heaves. (As the ground freezes, it can move houses; it's very powerful.) I don't know what the frost depth is here, but it can't be much. It just doesn't get that cold, and not for very long. Still, a 16" thick footing will start off 16" below the frost long, so we're off to a good start. If the frost line is lower, I'll have to adjust.

Conventional thinking is that cordwood should start a foot or so above the ground. Codes often require 8" between grade and wood. The idea is that rain can splash up and invite rot. I could just pour a concrete wall there, but it's not that simple. I need a layer of insulation splitting that wall, and separating one side of it from the foundation.

One option is to use concrete blocks, which are 8" x 8" x 16" after 3/8" of mortar. (You can skip the mortar, and use surface-bonding compound, which is stronger and simpler for the novice, but the math is harder so I went with mortar.) I drew 3 courses of blocks, getting us 2' above the footing. I could go with 2' if I make the outside of the footing flush with the exterior wall, but in this drawing I filled in over the footing. Hmm...

To make the lower exterior wall more pretty, I drew stone masonry. When I first started thinking about house building, I read a lot about slipform stone masonry. It's absolutely gorgeous, and you can use found stones instead of paying for siding or whatever. But there are some issues: how to the the thermal mass on the inside of the insulation without building two walls? How to attach things to the walls on the inside? Could we find a sufficient supply of beautiful rocks in this area, where it's mostly glacial till?  But those issues are all resolved in this design, so I went ahead and included an 18" course of stone masonry on the exterior.

I could replace the interior concrete block with stone masonry as well.  Or I could use concrete block inside and out, for simplicity, if I make the wall 18" instead of 16" (8" blocks + 2" blueboard insulation).

In this drawing I know I ignored are drains to remove water from under the slab and around the footing. I don't know if they're required around here, but they seem like a good idea.

I also ignored the vapor barrier. It's so thin that modeling it seemed like more trouble than it was worth. Still, getting it right is non-trivial, so I'll have to think about it more later.

Doing this drawing was a good exercise. It forced me to answer some questions that I hadn't hit before, because some ideas are impossible to draw.