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Stoker
Dec 15, 2004, 01:54 PM
Hi,
I am thinking of building a cabin with a slab-on-grade floor. My plumbing experience is pretty good for a DIYer, a cople of complete new houses, but never slab on grade. Reading over this forum, there seems to be a lot of plumbing problems in slabs. Should I reconsider the slab? If not, how do you complete the shower drain connections? Through the hole in the bottom of the shower? Do you know of a good plumbing book devoted in large part to slab plumbing? Most I have checked do not even mention slabs. Any help appreciated.
Stoker

speedball1
Dec 15, 2004, 03:51 PM
Hey Stoker,
I'm a south Flordia plumber. Every house, condo,or commercial building I've plumbed has been on a slab. What's your problem with slabs? Your other options are a basement or to jack the house up on a raised foundation creating a crawl space. If I were you I'd go with a slab. I'll look around for a book on slab plumbing but it goes down exactly the same as other plumbing except it's underground. If you have any questions about how to lay out a underground rough in I can probably answer them. Regards, Tom

Stoker
Dec 16, 2004, 09:42 AM
Hey Speedball,
Thanks for your reply. I like the idea of a slab in theory, just don't have any experience with them as far as plumbing goes. I want this cabin to be comfortable, light and airy, well insulated and relatively cheap. I think that's possible with a cost-saving a cost saving design, and my work. Yes, I need to know how to lay out the rought-in before pouring concrete. It seems to be more exacting than with wood floors. I Hope you find a good book to recommend. Whenever I have installed plumbing before, I've always had access from below the floor, as well as from the top. Are there any special types of shower hoop-ups for slabs? By the way, I notice you answer a lot of plumbing questions, and I am impressed with the answers, based on my limited knowledge.
Walt

speedball1
Dec 16, 2004, 04:58 PM
Hey Walt,

Before we get too deep in this thing, a few questions. Where are you planing on building. If up north then how deep is the frost line and will the cabin be used year round? Some of the books I've looked I've checked out tell you the plumbing rough-in is inbedded in the cement slab. This is misinformation of the worst sort. The only time that we rough in a unit and pour the floor and bury it is when we're building multi storied condos. I've done all the different types of rough-ins, from basements back in Wisconsin to crawl space and slabs in Florida. Believe me when I tell you! It's a lot easier to lay a piece of 4" pipe in a trench then it is to hold it up while you attempt to attatch it to a hanger in a crawl space. The reason I asked the location is that a slab may not be right for you. The pipes will be in position to freeze up in the winter time. If you're in a cold climate then you will have to "winterize" the cabin each winter to prevent burst pipes and fixtures. While this can be a hassle and time consuming it is fairly easy and a job for any homeowner. I'm not trying to talk you out of it, but you're getting into major surgery. Not only that but you'll be working with PVC which is a lot easier to install then cast iron but is a lot more unforgiving if you shoud make a mistake and miss a wall. I just want you to be aware of what you're getting in to. I can walk you through the plumbing part, no sweat! but while I've been exposed to the other building trades I'm no expert.
Answer the questions I've asked and we'll check to see if there will be any "special problems". Cheers, Tom

Stoker
Dec 17, 2004, 03:38 PM
Speedball,
I feel I am going to get some serious help here. :) The cabin will be in the mountains of West Virginia, elevation about 2760 feet. I like to use 32" as the bottom-of-footing depth, which should be fine. There is no frost depth code for the county. Lewisburg is about 14 miles away, in the valley, and their requirement is less than 32," though sometimes it gets colder there. It can be 20 degrees F below zero here, but that is very, very rare. A cold winter nowadays is maybe max. 5 degrees F. below zero, briefly. Cabin will not be used full-time, maybe a couple of months at a time unoccupied, but I plan to maintain marginal heat, about 45-50 degrees F. If a slab, I plan to insulate under it, at lest 4 feet around the perimeter, and the edges. Water supply lines will be in the walls, on the interior side of the insulation, or alternately, in a baseboard chase. I assume winterizing, should it be necessary, is about like winterizing an RV.
Walt

speedball1
Dec 18, 2004, 05:35 AM
Good morning Walt,
As a Florida cracker I'm getting goose bumps just reading about the winter tempertures that your cabin will endure. 5 to 20 degrees BELOW ZERO? Brrrrrrrrrr!
You said something that caught my attention, " I plan to maintain marginal heat, about 45-50 degrees F. If a slab, I plan to insulate under it, at lest 4 feet around the perimeter, and the edges. Water supply lines will be in the walls, on the interior side of the insulation, or alternately, in a baseboard chase. "
I like the idea of full time heat, I would be interested in your plan to insulate under the slab and surrounding area. Also keeping the water pipes above the slab will help. I assume the pump and supply lines will be included in the heated area, thus reducing the need to "winterize" the cabin to a minimum.
Has your location been graded and site prepped? Have you blueprints to scale on the structure? I assume this project will be put off until warmer weather arrives so we will have plenty time to hash out details and answer questions. In the meantime, MERRY CHRISTMAS TO YOU AND YOURS! Tom

Stoker
Dec 29, 2004, 02:21 PM
Hi Tom,
Sorry to take so long in getting back to you, but somehow, the forum email notification of a reply didn't work, and I was also unable to access the complete thread. Probably operator error. Hope you had a great Holiday, as we did. May 2005 be a great year you you and family!

Tom, the site has been cleared and septic tank installed (here, water well and septic locations have to be known and approved, etc), so as the well man brought his rig and fanilly gave up due to wet weather and early winter, things are a little out of sequence. He'll be back come spring.

I will be using blueprints designed by the University of Maryland and the Cooperative Extension Service. Plumbing, electrical, and insulation is not included in the plans, and will be pretty much up to me within the interior. No problem, I have wired and plumbed houses before, but never a slab. A stamped slab and maybe tinted concrete may be the finished floor. As for the inuslation under the slab, it's common practice in cold areas.
Walt




Good morning Walt,
As a Florida cracker I'm getting goose bumps just reading about the winter tempertures that your cabin will endure. 5 to 20 degrees BELOW ZERO?? Brrrrrrrrrr!!
You said something that caught my attention, " I plan to maintain marginal heat, about 45-50 degrees F. If a slab, I plan to insulate under it, at lest 4 feet around the perimeter, and the edges. Water supply lines will be in the walls, on the interior side of the insulation, or alternately, in a baseboard chase. "
I like the idea of full time heat, I would be interested in your plan to insulate under the slab and surrounding area. Also keeping the water pipes above the slab will help. I assume the pump and supply lines will be included in the heated area, thus reducing the need to "winterize" the cabin to a minimum.
Has your location been graded and site prepped? Have you blueprints to scale on the structure? I assume this project will be put off untill warmer weather arrives so we will have plenty time to hash out details and answer questions. In the meantime, MERRY CHRISTMAS TO YOU AND YOURS!! Tom

speedball1
Dec 29, 2004, 02:59 PM
Don't sweat the slab. You rough in and stub up exactly as you would a first floor rough. Think of the slab as a floor only with trenches and you don't have to hang the drainage from a floor joist. That's drainage. Let's talk water piping. What materal will you be using? When I retired we were still piping in copper but plastic doesn't require the equipment needed ro run copper, the down side is if you make a mistake with copper you can heat it up and make it right. PVC and CPVC isn't all that forgiving. You will have to cut it out once it's primed and glued. My Xmas went fine. Hope your New Year is a happy one. Regards, Tom

Stoker
Dec 29, 2004, 05:37 PM
Maybe a new matériel this time, such as the newer plastic pipes, which can be bent without all the fittings. I have used copper and cpvc. I like copper best, but it's time consuming. Maybe the new plastic is good?
Walt

labman
Dec 29, 2004, 08:00 PM
PVC/CPVC are cheap and fool proof. You may save a few fittings with XLPE, but the fittings you have to use are a pain. If I am going to pour concrete over a pipe joint, I would want it to be PVC.

I lurk around plumbing, but usually leave answers to Tom. Been spending too much time at church fighting Sloan Valves and stops lately.

Stoker
Dec 30, 2004, 11:50 AM
Hi Labman,
I hope you mean that you have been working on church plumbing, and not (what a vivid imagination I have!) praying about "sloan heart vaves" and stops! Guess I know too many folks who have had by-pass surgery. Back to pipe--I actually used cpvc for both hot and cold lines, but suppose that was not necessary. Probably pvc is more durable, and should be fine for cold water. Thanks.
Walt

brob1969
Jun 19, 2005, 02:22 PM
I am in the process of constructing a new bathroom on the back of my home in St Petersburg, FL. I have dug the footers and have the grade where it needs to be. I have pulled all of the necessary permits for construction. My question is: When installing the plumbing, does the vapor barrier and wire go above or below the plumbing? Do I get my plumbing rough-in inspection first, then backfill around the plumbing, put in the plastic and wire? Or, do I install the plastic sheeting and wire then the plumbing? I have done a good bit of plumbing before, this is just the first time doing plumbing under concrete.