Help me solve a layout puzzle

For years I've been designing (in my head, on paper, in Sketchup, etc.) and redesigning the house I'd like to build in about 15 years. Probably an architect or someone with similar training/experience will help me put the professional touches on it, but I am trying to hash out the big ideas first on my own. Designing a house entails solving a lot of little (and some big) puzzles. The puzzle I'm chewing on right now is this:

I want my mechanicals clustered together as much as possible in a central "core". Some of these will require venting: drains, for example, as well as a water heater if it's gas-powered, and I'd like a properly vented hood over my kitchen stove too. And I am handwaving away an indoor fireplace/heat stove right now, though that is a possibility too.

Rather than hiding these off in some back corner, I'd like them centrally located, maybe even "featured" and out in the open, for several reasons: 1) I think they have a utilitarian beauty, 2) central location means less material needed to e.g. run plumbing to various sinks, and 3) it makes them easier to service.

But at the same time, I don't want any roof penetrations.

Assuming a generally squarish footprint and a shed (i.e. 1-facet) roof, to me this looks like a conundrum. Is it one? If so, how would you solve it?

I know vents can go diagonal some, but how much? Is there a rule of thumb (like for every foot of rise a vent can go diagonally X feet of run)?

Beauty is in the eye of the beholder, but I'd think you'd have to work on "beautifying" some of them! As a rule, I agree with the concept of particularly, keeping plumbing grouped and in the core to decrease the cost, length, and risk of freezing. My husband also wants to avoid roof penetrations, but he hasn't gotten as far as researching issues such as slope. Be aware, that sewer vents smell like "sewer" - so if venting through a wall, you will need to consider wind directions and nearby outside uses, and window placement.

1. What is your anticipated foot print of the building?
2. Are you prepared to spend extra money on materials to make this work? For example, personally I consider black plastic sewer pipe undesirable as living room décor. However, a sink we installed in a small kitchen, needed the plumbing to be as out of the way as possible, so he used copper and extra fittings to curve it to the back of the cabinet and put a clear finish on the pipes to keep them looking shiny and coppery - something like that could totally do the "steam punk" look. However, the kitchen had an unfinished basement below it, so we did an long drain pipe, and put the trap between the joists accessible in the basement. Once he thought about it and started working on it, he decided this is great from the functional point of view, because you don't need to crouch in a cabinet to clean out the trap!
3. I totally like the concept of simple roofs due to both the costs and the lower fire risk. However, I've read places that a shed roof isn't as strong as an A frame roof (yeah - probably another professional name...) Point is, a triangle is stronger, so if high winds are a risk, something I would consider. The bonus would be the triangular wall might give you a spot for several of the necessary pipes to exit.
4. Also, depending on the size of the building, it is possible to cluster the pipes, but not in the geographical "center" of the foot print.
5. I would also want to consider if small pipes could be grouped inside of a large pipe from the dust-bunny control point of view. Many "utilities" are also a paint to clean around - even true of fridges and stoves. Mine are desperate, but I really need help to get them out of their cubbies.

Jay, thanks for your thoughtful reply.

To answer your numbered questions...

1. Obviously it's very far in the future still but I anticipate somewhere in the neighborhood of 30x30 feet.

2. Regarding suitability as decor, my options would seem to be:
a) use different (probably more expensive) materials that are easier on the eyes
b) hide stuff or put stuff in unconventional locations
c) (I had this idea as I was typing this) build a nice-looking glass-doored cabinet around the utilities, and then all of a sudden the eyesore becomes a curiosity & a positive conversation piece.

3. Yes, I will have to keep the snow load/wind resistance thing in mind. Right now we are eyeing the Four Corners area, but that could change.

4. I'm hoping that angling them out the nearest wall will be possible.

5. Good point!

Ned,

When I was designing my house I decided to put a mechanical room on the south-east corner then the next one is the bathroom and then the kitchen, so all the sewer and water pipes are not longer than 470 cm (15.5'). Sewer pipes are under the slab, so I welded them from 316 stainless steel to last quite for ever. Water pipes are in the slab, also from 316. Water and sewer pipes reaching to the bathroom sink, toilet (toilet sewer is through the slab) and bidet are going through the wall between the mechanical room and the bathroom. Easy to access/clean. In the mechanical room I have 4" vent pipe going through the roof. And another 3" vent in the corner of the kitchen. So everything is contained in the south-east corner of the house.

If I had to change something, I would put the chimney on the bathroom/kitchen wall (instead kitchen/dining room) so I could build the cooking stove close to the bathroom wall, but nonetheless I would still need another chimney for the main heater and in this case I would place it in the ridge of the roof, so the masonry heater would heat two bedrooms and the dining room. At the same time, I don't live in a place with cold winters, so I'm happy with the current chimney layout.

Just learned about AAVs. Basically a valve you can install under sinks/etc. that acts as a plumbing vent. That solves this problem for the most part!

You can’t use aav’s on every fixture, you have to have at least a main stack vent. But you can tee together all the plumbing vents and go out a wall. It may or may not be code to put an outside stack to get it above the roofline, but it is a really good idea.

To vent a gas furnace or water heater out the wall, it needs to be a power vent, forced draft unit. Not uncommon, but need a little more power.

Think hard about a wood burning chimney. They do not work near as well when run out the wall. That is probably going to be my only roof penetration. Doing that right is easier and cheaper than trying to go out the wall, plus it saves so many hassles of getting it to draft or cleaned.

R Scott, I take your word for it that one cannot use AAVs for all plumbing fixtures, but I'm curious to know why not.

And if that's the case, I'm still looking for info on whether/how the common vent can be run out a side wall even when all plumbing fixtures are 6 or more feet to the interior.

As for the furnace chimney, seems like one solution is to not use a furnace that needs a chimney (i.e. electric), or another is to use a high efficiency class iv furnace whose exhaust is cool enough to go out the side wall.

My house was designed with passive solar innovations.

All plumbing is on the south side of the house. First kitchen, then bath, then laundry room.

The electric panel is in the laundry room.

I don't have central heat or AC though in all the houses I have lived in that unit was in the center of the house or in the laundry room.

Ned Harr wrote:R Scott, I take your word for it that one cannot use AAVs for all plumbing fixtures, but I'm curious to know why not.

And if that's the case, I'm still looking for info on whether/how the common vent can be run out a side wall even when all plumbing fixtures are 6 or more feet to the interior.

As for the furnace chimney, seems like one solution is to not use a furnace that needs a chimney (i.e. electric), or another is to use a high efficiency class iv furnace whose exhaust is cool enough to go out the side wall.

Decomposition in a sewer or septic creates gases and a positive pressure. If you don’t have an open stack somewhere it will bubble back the P trap and you will smell it in the house.

You can run the plumbing vents sideways as far as you want as long as you maintain a drain slope do any condensation runs down to the drain. Usually that is done in the attic, but it can be in the living space. My old neighbor built an earth sheltered house with three feet of dirt on the roof, he ran all the vents out the wall. Some were hid behind cabinets, some were steampunk industrial on display.

I agree on furnace and water heater, it is wood stoves that I make an exception.  There are ways to make a through wall chimney work but they usually compromise draft performance and location in the house. And cost WAY more than a straight chimney would in a simple house.

Ned Harr wrote:Rather than hiding these off in some back corner, I'd like them centrally located, maybe even "featured" and out in the open, for several reasons: 1) I think they have a utilitarian beauty, 2) central location means less material needed to e.g. run plumbing to various sinks, and 3) it makes them easier to service.

Just a oddball concept, but would a central courtyard feature fit the bill?

source

These are gardens designed more to look out at than be in - so viewed through a window. They can be as utilitarian as you like, but still allow the services to vent through an outside wall, access though a window or patio door.

It does give you more outside walls to build/insulate but may be an interesting concept to consider.

Nancy Reading wrote:

Ned Harr wrote:Rather than hiding these off in some back corner, I'd like them centrally located, maybe even "featured" and out in the open, for several reasons: 1) I think they have a utilitarian beauty, 2) central location means less material needed to e.g. run plumbing to various sinks, and 3) it makes them easier to service.

Just a oddball concept, but would a central courtyard feature fit the bill?

source

These are gardens designed more to look out at than be in - so viewed through a window. They can be as utilitarian as you like, but still allow the services to vent through an outside wall, access though a window or patio door.

It does give you more outside walls to build/insulate but may be an interesting concept to consider.

Yes, I did consider this idea! They are cool aesthetically which I think would be the main reason to include them, because I imagine you'll lose more efficiency from all those extra walls/windows/seams than from one or two small roof penetrations. (So, I personally would probably pass on the interior courtyard, but smile approvingly at those who include it in their designs.)

R Scott wrote:

Ned Harr wrote:R Scott, I take your word for it that one cannot use AAVs for all plumbing fixtures, but I'm curious to know why not.

And if that's the case, I'm still looking for info on whether/how the common vent can be run out a side wall even when all plumbing fixtures are 6 or more feet to the interior.

As for the furnace chimney, seems like one solution is to not use a furnace that needs a chimney (i.e. electric), or another is to use a high efficiency class iv furnace whose exhaust is cool enough to go out the side wall.

Decomposition in a sewer or septic creates gases and a positive pressure. If you don’t have an open stack somewhere it will bubble back the P trap and you will smell it in the house.

You can run the plumbing vents sideways as far as you want as long as you maintain a drain slope do any condensation runs down to the drain. Usually that is done in the attic, but it can be in the living space. My old neighbor built an earth sheltered house with three feet of dirt on the roof, he ran all the vents out the wall. Some were hid behind cabinets, some were steampunk industrial on display.

Awesome, great info! Mystery solved, and I have a couple friends who were wondering too so I'll pass this info along.

Another reason the general approach for sewer vent stacks is to penetrate and go above the roof level is to help make sure the smell doesn't hang around where people will be annoyed by it, or for it to go into open windows.

True example: an acquaintance with a septic tank and field system, was complaining he was getting sewer smells on his deck, which was built about 8 feet above the tank. Normally, there are rules saying that the tank clean out needs to be covered by dirt, but there are also rules about getting them pumped every 5 years (which for permies is generally unnecessary, but the rest of the world often isn't as careful) which make shovelling it off a pain. He didn't like the idea of having dirt on top, so I gave him a coffee sack which we filled with mulch from my mulch pile. That was enough to either absorb the smell, or help it dissipate enough that the deck was a pleasant place to sit.

So in general, I'm in the "the fewest holes in the roof possible, the better" camp. However, that requires paying attention to traffic patterns, year-round weather patterns, and even extreme weather patterns, so the alternatives can be planned well. You may generally be in an area with light breezes, but we lived through a "heat dome" event when the evening breezes stopped and the temperature was much higher than expected. This would have been the kind of event when a marginal set-up could easily turn ugly!

Jay Angler wrote:Another reason the general approach for sewer vent stacks is to penetrate and go above the roof level is to help make sure the smell doesn't hang around where people will be annoyed by it, or for it to go into open windows.

True, though there are standards regarding the placement and height of vents that are designed in part to mitigate this. "Above the height of the roof" is not always necessary so long as the stack is far enough away from operable windows for example.

Have you thought of venting into buckets? Or an old hot water heater? These options would have an old nylon stocking attached to the hose. Place hose inside the lid of a 5 gallon bucket before attaching the stocking. Be sure to use clamps on the inside and outside of the lid. Drill 1 inch holes (use your discretion) towards the bottom of the bucket (I use 5 holes).
For the hot water, try coiling copper pipe around the inside tube of your rocket stove. It’s efficient and easy. I got the idea online when searching off-grid hot water without electricity.