Question:
If a person with plumbing experience were asked to design a 2-bath house with the simplest possible plumbing, how would those two baths be configured? How would the utility area (water heater, laundry, etc) relate to the two baths? Kitchen?
Just curious.
Replies
Nanny, you gotta give us more than that to go on, LOL....
Is this hypothetical house a ranch, a split-level, a two-storey, or what?
Do you have separate tub & shower in the 'big' McMansion bathroom, or are they both Levittown specials?
Is there a basement? And if so, is the sewer connection low enough to gravity-drain waste water from there, or would a pumping station be required?
Do you require more than one sink in the kitchen and if so which one has the garbage disposal if any? Dishwasher yes or no?
And do you care about pressure drop under multiple use conditions?
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
I think you missed the point a little. I'm not asking about MY house (necessarily), I'm asking you - the person with plumbing experience to consider a home design.Look at it this way: you've been entered in a contest to see who can plumb a house fastest. The cost of materials isn't a big issue so this isn't really about cheapness. It's about simplicity.As you grab your bag of tools and prepare for the starting gun to pop, what do you hope this hypothetical house looks like?...BANG!....
Assuming city water and sewer, with a sewer connection below the level of the main waste line coming from the basement:
House layout:
Full basement plus 1 or 2 storey house.
Laundry/mechanicals in one room in the basement, directly under the kitchen.
Basement bathroom backing up on the other side of the laundry room partition wall, which is not a simple wall but is built as a three-foot-wide utilities chase with doored access. City water entry and meter is in this chase.
Main bathroom on first floor backing up on the same utilities chase, on the other side of which is the kitchen.
No bathrooms on second floor; it's good exercise to sleepwalk down to the can when yer prostate starts gittin' aged. Helps prevent arthritic knees....
Plumbing specs:
¾" rigid copper manifold after the water meter.
¾" rigid risers in home-run format from the manifold to each wet room
½" rigid supply lines to each sink, toilet, bath in each room
½" ball valve cut offs at each unit
¾" ball valve cut offs at the origin of each riser
Non-hubbed cast-iron waste stack down the chase feeding ABS waste line underslab to the sewer connection.
ABS vent stack up the chase to the roof.
ABS traps and drains feeding the CI waste stack.
Floor drain in the slab inside the utilities chase, plus another in the laundry room.
Cleanouts and so forth strategically placed to insure ease of maintenance. Access wells cast in slab for cleanouts and for bathtub p-trap (for the basement bathroom). Etc....
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
Thanks for the response!Just for the heck of it, let's say the house you describe was the subject of your speed plumbing contest. How long would it take to rough plumb? I assume the final plumb is too subject to particular fixtures to guess.Just curious.
If I framed it myself (heh, heh, heh) it would take me 1½-2 days to rough in the copper and another 1-1½ days to rough in the DWV. Working alone.
But I'm slow. Put my plumbing sub's no. 1 residential plumber with me on that job, and we'll knock the whole thing out for about 18-22 man hours. He and I have worked together for over 10 years: I sweat and he glues....
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
Also, especially in a situation like this, where the plumbing is in a compact area, it makes a big difference whether you're building one home or 20. There are enormous possibilities for "assembly line" production when the plumbing is arranged in the way we've been discussing.
Simple and fast plumbing may not make a good house design. When a house is designed accomodating the plumbing and fixture layouts should be part of the process.
I would not design my house around the utilities, I would make sure the design works with them. When I built our home most of the plumbing fixtures fit within the framing layout. One tub drain just hit one side of a tji floor joist. I should have paid attention to that when designing and framing.
With over 8,000 feet of pex for radiant heat, 400 feet of 1" copper for zones, and at least that much for hot, cold, recirculating, and drains, everything worked out well.
(also to CapnMac)I agree that aspirations for simple plumbing shouldn't trump good design. But I believe good design can encompass simple plumbing. As a general principal, I prefer simplicity wherever possible and reasonable. I also like the philosophy that says "just because a thing can be done doesn't mean that it should be".
I kind of get the impression that you're thinking along the lines of a moderate-cost, low-maintenance home, such as a retired couple might want.I'd say that a big part of it is to avoid extra added complexities for things you don't need -- fancy steam bath, recirculating hot water, and the ever-popular, never-used whirlpool. Under-the-floor hydronic heating also falls into this category, sort of. It's nice to have warm toes, but the stuff is expensive to install and failure-prone.
As a general principal, I prefer simplicity wherever possible and reasonable. I also like the philosophy that says "just because a thing can be done doesn't mean that it should be".
I think you have a good philosophy on how things should be done.
What do you mean by "simple". Cheap?? Reliable??
When really trying to cut costs, designers will place all of the plumbing together, to the extent possible. Typically, toilets will back up to a single main drain stack, and everything else will be within a few feet of there. Eg, the drain end of the tub will be against the same wall as the toilet, as will the sink.
This also actually helps improve reliability somewhat, since the drain lines are kept as short as possible, and, with the kitchen sink or another bath on the other side of the wall, the wall is necessarily interior, so problems with freezing are essentially nonexistent. And, if the water heater can be located in the same area (closet in kitchen or in basement below), the wait for hot water is minimal, as are heat losses in the pipes.
But, of course, this arrangement doesn't fit a McMansion, or a sprawling ranch house where one might want bathrooms at opposite ends. But it is typical of the "shotgun" homes of the 20s-40s, and similar small homes since then.
The economics have changed a little, though. With plastic pipe, both water and drain, (and with increased labor costs) the cost savings one realized by minimizing the length of pipe in the classical compact design is not as significant. More significant is any savings in installation cost. A compact design helps some, but simply avoiding awkward setups is the main thing to worry about.
With regard to reliability, the main issues are probability of drain clogs and the reliability of fixtures. The regular water piping (aside from some of the less-than-successful plastic schemes) is essientially so high that it can be ignored in the equation.
Drain clogs can be a complicated issue, but minimizing horizontal runs (and carefully controlling their slope) is key. Here it helps if the overall design allows for the optimal slope, vs forcing a compromise due to clearance problems.
For fixtures, the key is basic quality and simplicity. Stainless faucets with ceramic valves are generally a good value, as are heavier weight stainless steel kitchen sinks. For bathroom sinks, either good quality true solid-surface sinks or porcelain are the way to go (with basic porcelain units generally being cheaper). The immitation solid-surface vanity tops (basically a plastic coating over some sort of fiberboard core) are very short-lived.
Toilets are another matter entirely -- worthy of a series of books, probably. The problems one can have with a toilet are primarily clogging and failures of the fill/flush mechanism in the tank, plus occasionally liming of the water jets. Which of these issues is most important will depend a lot on the usage pattern of the toilet.
One non-obivous thing that can affect cost, reliability, and user satisfaction is the solidness of the floor in the bathrooms. A weak, bouncy bathroom floor can cause a number of problems, especially with toilets.
Thanks for the detailed response!How much does it matter whether the baths are back to back vs. stacked?Does it really matter much whether the kitchen is 4' away or 40'?My question really has more to do with simplicity than pinching pennies. Right or wrong, I always envision water running through the walls and floors of a finished house as just asking for trouble. I like the idea of minimizing it.what about conventional plumbing around wood framing vs. under the slab in slab on grade/ no basement ramblers? Pros? Cons?
Stacked vs back-to-back is pretty much equivalent, though the venting gets a little more complicated with a stacked arrangement.The longer a horizontal drain run, the more potential there is for problems (partly because ideal slope becomes harder to maintain, and also because of the "separation of solids"). There's no magic number, though, so long as reasonable slope is allowed for. But, given the standard 1/4" to the foot slope, and figuring that you can maybe manage about 6" of total slope in a joist bay (depending, obviously, on size of joist and size of pipe), you're looking at somewhere around 24 feet before you have to start working at maintaining the slope, or have to duck below the joist. If running across joists you have maybe half of that, since you must keep holes in the joists relatively centered.The three main problems with plumbing under concrete are:1) It's subject to displacement during the concrete work, and not easily inspected after that to assure that it's all OK.2) If there is a displacement, or a change of plans, redoing things is expensive and messy.3) Similarly, if/when something goes wrong, repairs are difficult.For practical reasons, burying at least some drain lines under concrete is often required, and since the major drain lines are fairly large and stiff, they resist damage/displacement fairly well (though there's substantial risk of the slope being disturbed in some cases).Water lines, on the other hand, should not be buried under concrete if this can be avoided. They're too easily damaged and too apt to leak and cause problems down the road. (An option here is to place some sort of "conduit" under the concrete, so that water lines can be snaked through later. This is becoming more practical with flexible plastic piping, but check with your local inspector before trying it.)On a slightly different topic, remember that whatever goes down must also go up -- drains need vents. Thankfully, vents don't have major issues with slope, etc, but still, try to avoid a situation such as when a bathroom is positioned so that it's vent "wants" to go up right through the center of the room above. Also, things like wet kitchen islands are a b***h to vent. Re reliability, having a setup where the vents can all be combined (perhaps in the attic) into only one or two roof penetrations will reduce chances for roof leaks and relieve roof "clutter".
Thanks again for the good observations. I, too, hate roof "clutter". A 4-plex near here has a roof that looks like a chia-pet.
Edited 5/16/2005 7:45 pm ET by NannyGee
One other thing to keep in mind is freezing. If you're in a place where temps regularly dip below about 15-20F in the winter then it's good to avoid any plumbing in the outside walls. (In fact, in some areas code won't allow plumbing in the outside walls without special protection.)It's especially important to keep water pipes out of such situations, but even drain pipes in outside walls can freeze.There are probably opposite considerations for warm climates, but I'm not up on that.---Thought I'd add that there are a number of other location-dependent issues. If you have corrosive water, eg, then copper plumbing may be a bad idea, even though in other situations it is more durable than plastic.And of course, things like earthquake and hurricane proofing can impact plumbing in several ways.It's good to give a thought to specific geographic issues.
Edited 5/16/2005 8:12 pm ET by DanH
The wall down the middle of the house would be a double 2x4 12" OC (a lovely great huge wet wall). The baths would be identical, "single wall" (tub, w/c, lav, in a row) layouts back-to-back. The kitchen would back up to the laundry room, likely with mop sink & wash connections back-to-back on the kitchen sink & fridge connections.
Oh, and not one hose bib, either.
That would make for the simplest plumbing plan, and the least amount of plumbing maintenece, too.
But, that's looking at it from the least complicated plumbing standpoint. Most folk prefer their kitchen sink to have a window, so it needs and exterior wall. Most don't want the bathrooms occupying the "best" interior spaces, either (and back-to-back rarely ever "programs" well with bedrooms.
Don't get me wrong, plumbing is the art of making an elegant mechanical solution from the architectural needs of a house.
So, and this from years of architectural experience, design the baths to "work," then associate them well to the rest of the rooms--the plumbing will follow.
Now, allowing for 2x8 framed wet walls in baths will make your plumber & framer a lot happier. Taking care that the vent can run from the first floor through the roof without needing a jog to "hit" upper level floors is also good. Those are the "little things" that make for better plumbing.
But, that's just my opinion, others differ.