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Pier foundation – how much space would the plumber, HVAC people prefer?

LucyF | Posted in General Questions on

We will be building a house for my brother in Upstate SC next year. We are currently in the design phase and having a disagreement on where to put the downstairs kitchen and bathroom with the plumbing lines.

I am thinking along the lines of what makes the house the most resilient and easiest to repair and who knows what he is thinking. The house will be on a pier foundation because it is near a flood zone. The land is sloped so that the piers at the driveway side will allow a crawl space of 3 feet or so and probably 6 feet at the other end near the pond and the flood zone.

My thinking is that to have to most access to the plumbing lines, etc. It will be easier to work at the 6 ft end rather than crawl under a house at the 3 ft end. As I have never done any major plumbing (only glued together PVC for one washing machine drainpipe), I don’t know what a plumber would prefer. If it doesn’t matter really, that doesn’t help me win the argument but it would be good to know.

I trust you guys, that is why I am posting here even though the question is only peripherally involved with green building. Thank you. Lucy

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  1. GBA Editor
    Martin Holladay | | #1

    Q. "How much space would the plumber, HVAC people prefer?"

    A. Eight feet. It's called a basement. That's what they would prefer. Sometimes, however, all they get is a crawl space.


    I'm a plumber here in North Carolina and would be very comfortable working in any crawlspace between three and seven feet tall. I'd rather not have to bring a ladder into a crawl space.

  3. LucyF | | #3

    That's funny, Martin. Ok. Since you brought the idea up, what is your opinion on putting a basement in this location. We get some torrential rains here. The house location is near a creek and a pond. We've seen a flood that came to about 15 feet from his current home (a trailer) from just one intense rain. I haven't talked to an engineer yet, but do think a basement would work there? I figured it was safer to have the house on piers rather than a basement because of the high water table.

    Where we intend to build is not technically a flood plain but it is just a few feet away.

    Thank you again. Lucy

  4. GBA Editor
    Martin Holladay | | #4

    There is no way I can make a judgment about whether you have a good site for a basement without a site visit and local knowledge. If people you trust advise against a basement, that's good enough for me.

    If you have a crawl space, try to keep it at least 3 feet high, as Michael suggests.

  5. gusfhb | | #5

    How much space does the plumber want?

    All of it.......................

    Same with the 'lectrician


    we really don't want all the space, we just need certain things to flow downhill, so we want to get our drain lines run before the AC ducts go in

    and we want enough options to locate the full height of the water heater in a central location so we don't have hot water lines over thirty feet from any fixture

    and we want easy access for drainage, maintenance and replacement with room over the top for connections with out elbows (copper sweep connections etc, not close elbows)

    and we want PDFs for all fixtures at rough-in, especially any wall hung faucet or tub valves

    and we have very specific venting and condensate requirements for Propane and NG demand water heaters, so if you have something especially green in mind get us model numbers and PDFs of those install manuals

    and water heater pop-off drains should be to a floor drain to outdoors above grade, don't make us pipe the pop-off out of the building directly please.

    Finally, "Hots on the left, colds on the right, Sh** runs down hill, the boss is a jerk, and paydays on Friday."

  7. user-659915 | | #7

    With all due respect, the plumber will be working under the house for just a few days while the kitchen and bathroom will be in use for decades, so if the house is to have any claim to longevity these critical, expensive-to-relocate spaces must primarily respect the long-term convenience of the occupants. Don't make the tail wag the dog. Let your brother put his kitchen where it makes sense for its purpose, and then adjust your foundation to make sure the plumber has as much working room and access as he/she needs.

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