FHB Logo Facebook LinkedIn Email Pinterest Twitter X Instagram Tiktok YouTube Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe
Log In
  • How-To
  • Design
  • Tools & Materials
  • Restoration
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
Log In

Discussion Forum

Discussion Forum

help with cutting concrete slab

Shep | Posted in Construction Techniques on July 9, 2007 11:06am

I need some advise.

My church has some serious plumbing problems. The cast iron waste lines under the building are pretty much rotted away, and need to be replaced. Waste is escaping from the pipes, into the ground water.

The plumbers spent at least a week jack hammering the floor in the kitchen to get to some of the pipes, and another week or so re-plumbing everything, and have everything there fixed.

But now they need to replace the pipes to the front of the building, probably another 60′ or so of jack hammering.

Patrt of the problem here is that there’s a room over part of the area, with about a 28″ crawl space between the room’s floor, and the slab the pipes are buried under. The room is about 14-16′ across, with a block wall on either side.

I’d like to know if anyone has any suggestions on how to gain access to the pipes without blowing up half the building. I’m thinking of renting a concrete saw to cut a channel, but never used one of them before.

And part of my reason for finding a solution for this is that I don’t think it’s very wise to be paying plumbers wages to jackhammer a concrete floor. The guy from our church who’s been overseeing the project has been overwhelmed by the scope of the work. I’d like to make things a bit easier for him, if possible.

 

Reply
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Replies

  1. peteshlagor | Jul 09, 2007 11:34pm | #1

    Then get him some volunteers with sledgehammers.

    You won't believe how much dust will be created with the saw.

     

     



    Edited 7/9/2007 4:34 pm ET by peteshlagor

    1. FastEddie | Jul 09, 2007 11:36pm | #2

      There's no dust from a wet saw. "Put your creed in your deed."   Emerson

      "When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

      1. peteshlagor | Jul 09, 2007 11:57pm | #4

        Bottomline, Vintage is right.

        I've cut so much and have all the tools, but these guys are so cheep and get it done so quick it's a no-brainer.

         

        1. FastEddie | Jul 10, 2007 12:36am | #5

          Agree.  Unless the labor + tool rental is cheaper than the contractor."Put your creed in your deed."   Emerson

          "When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

          1. peteshlagor | Jul 10, 2007 12:41am | #6

            Once I needed two 7" and one 6" cores put thru the ceement foundation + brick to vent my shop.  $70.  Took all of 30 minutes and clean as a whistle.

             

          2. FastEddie | Jul 10, 2007 12:44am | #7

            Cores are different than straight lines.  Anything bigger than a one inch hole definately should be subbed out."Put your creed in your deed."   Emerson

            "When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

          3. peteshlagor | Jul 10, 2007 12:51am | #8

            Then again, straight lines introduce bonding issues in the repour...

            Pins?  No pins?  Undermine? 

            It's always sumpin'.

      2. Shep | Jul 10, 2007 05:33am | #12

        That's kind of what I was thinking.

        How are they to operate in confined spaces?

        1. Hudson Valley Carpenter | Jul 10, 2007 03:13pm | #13

          Whatever you decide, don't use a gas engine saw anywhere inside!  I made that mistake once with a rented wet saw.  Thought that I'd be done quickly, before the exhaust fumes got bad.  Serious error IMO.  I almost passed out, just barely crawled out of that basement. 

          Even with all the basement windows open and a big fan at the top of the stairs, pushing the air out the open back door, that little gas engine loaded the area with carbon monoxide in just a couple of minutes. 

        2. Hudson Valley Carpenter | Jul 10, 2007 03:16pm | #14

          Shep,

          Have you considered re-routing the drain?  Going out a side wall and around the building? 

          1. Shep | Jul 10, 2007 06:24pm | #16

            Umfortunately, the way things are laid out, re-routing the pipe isn't an option. Everything feeds into a holding tank, and then has to be pumped up by sewer ejector pumps to the street.

            The church was built in the '60s, basically on a land fill. We're enough below street level, that everything is a pain to deal with. Plus we get flooded regularly.

            But I understand that we got a great deal on the property when we bought it. <G>

            Edit to add- Thanks for the warning about using a gas powered saw. I really hadn't thought about the CO fumes, but considering the area we'd be cutting in, it's a real possibility that there would be a problem.

            Edited 7/10/2007 11:26 am ET by Shep

          2. dovetail97128 | Jul 11, 2007 01:39am | #22

            Shep ,
            Is this line that is being replaced on the pressure side of the ejector pump ? it doesn't sound like it is but just wanted to clarify. SamT has the best idea so far IMO, drill a new pipe along side the old and make connection at each end outside the block wall.
            "Poor is not the person who has too little, but the person who craves more."...Seneca

          3. Shep | Jul 11, 2007 02:08am | #23

            At some point, the pressure side to the street probably will have to be replaced. It does have a crack in it, but nothing too big ( yet).

            Is there a way to drill under a slab? We'd have to go about 25-30 feet from the current repairs, to where we could connect to the rest of the line in the boiler room.

            edit to add- oh, yeah, I just remembered that the new line would have to go thru 2 concrete footings, supporting walls above.

            It looks like there's really no easy way to do this.

            Edited 7/10/2007 7:10 pm ET by Shep

          4. dovetail97128 | Jul 11, 2007 02:34am | #24

            Shep,
            Yes there are ways to drill under slabs and buildings. The foundation walls (if accessible from one side) can be predrilled and a directional boring machine used from a distance away. I have seen it done for elect. conduits , and am aware of it as the technique is used quite often to bore under roadways for gas lines etc.. Whether is is cost efficient is another question. I would certainly investigate it though as the cost of a few phone calls is cheap. Best lead for companies that do that work may be through your local utilities."Poor is not the person who has too little, but the person who craves more."...Seneca

            Edited 7/10/2007 7:36 pm by dovetail97128

          5. JohnSprungX | Jul 11, 2007 03:45am | #28

            Here's the one I have, the Partner K3000 electric 14" wet saw:

            http://contractorstools.com/partner_k3000.html

            It won't be as fast as the big ones, but with a volunteer operator, that shouldn't be a big problem.  It'll fit in the crawl, and not make poisonous fumes.  28" is a nice big crawl space, you can go on hands and knees there.  It's where you can't get up on your knees that it's really a drag. 

            The water will be a mess no matter which saw you use, but this is a crawl space.  You definitely want to cut wet, both for blade life and dust is lots more obnoxious than glop.  Check your local rent-all places.

             

            -- J.S.

             

          6. Hiker | Jul 11, 2007 03:03am | #25

            If you are over an old landfill, be careful of methane or hydrogen sulfide gas or other gases that may have accumulated under the slab.  This is a potentially deadly situation that should be evaluated carefully.  A 28" crawlspace is about a confined space as you get.

  2. vintage1 | Jul 09, 2007 11:46pm | #3

    shep,

    I would contact a concrete cutting company. 

    On previous projects, I have rented saws (both electric and gas) to cut my own slabs.  It made a dusty mess and took a long time.

    My last project that required cutting a slab, I called a cutting company and they cut over 100 LF (actual length of cuts) to create several trenches for the new plumbing work. 

    They were done in under 3 hours and this was all done in the basement of an occupied home.  They used a hydraulic powered wet saw.  Hydraulic unit stays outdoors, two hoses come in w/ the saw.  Relatively neat, clean and done for less than $350.00.

     

  3. User avater
    SamT | Jul 10, 2007 01:13am | #9

    Push a 20' pipe under the slab section with crawl only access.

    SamT

  4. AzDiscDog | Jul 10, 2007 01:25am | #10

    I'll second or third vintage1's advice.

    Find a concrete cutting company, have them come out with a hydraulic concrete saw.

    I've been there, done that with the cast iron pipe replacement in the basement for the kitchen drain line. I spent hours and hours jackhammering out the area for the new bathroom rough-in. We were looking at an additional 20' due to the pipes being corroded. Called up a local firm that does a lot of highway work and they were in and out in just a few hours.

    It is kinda messy, but far less so than with a gas powered concrete saw. Put up plastic to shield the over-spray.

    If you've got 60' to run through, don't waste your time trying to do it yourself. Sub it out to a pro and call that the best money spent.

    Otherwise, can you re-route the drain pipes? :-)

    Glen

    1. Shep | Jul 10, 2007 05:31am | #11

      I talked to a concrete cutter this AM, before I posted this.

      The problem, at least in his eyes, is that there's several levels to move his machine up and down. He said it weighs 750 lbs., and can't get it down some of the stairs.

      Also, the big problem is getting to the slab in the crawlspace below the classroom floor. There's no way to get his machine there without removing the floor, which is  tensioned concrete panels. If we cut into them, the whole floor is compromised.

      My thought was to hire someone with a big wet saw who could make the cuts. I was thinking of opening up the walls at either ends of the crawlspace to gain access, and using a mid-size jack hammer once the cuts are made. I know working in a 28" high space will suck, but I'm thinking it would be less of a pain than having to deal with the floor above.

      This job involves the 2 things I like doing the least- concrete and plumbing. But I might just do the concrete cutting if it will save my church a bunch of money.

      1. AzDiscDog | Jul 10, 2007 04:12pm | #15

        Hi Shep,Sorry to hear the first concrete guy wouldn't be able to tackle the job. One of your other comments makes me think the cutter you talked with doesn't have the saw that I was envisioning. The guy who cut the line for my basement had this massive circular saw with a 12" or 14" blade that was connected back to his truck through two monstrous tubes. The tubes supplied the fluid that spun the circ saw blade. So long as your project is within the reach of the hoses he has, there shouldn't be a problem getting the saw to your site.I do recall my plumber saying that there were only a few crews in town who used that type of saw, so you may have a similar situation and may need to call around a bit.On a completely different note, I started thinking about the safety of cutting / hammering out the concrete underneath that crawlspace. Assuming the pipe has been installed for a while, you don't know what settling may have occurred around the unions in the pipe. In my case, the floor dropped out a good 6 or 8 inches while the guy was cutting. He was ready for it, so he didn't get hurt, but how well would somebody stuck in a 28" crawlspace do?Might be worth getting some extra opinions on what can be done to resolve this. There may be a different solution available.Glen

        1. Shep | Jul 10, 2007 06:31pm | #17

          I'm almost positive that the ground under the building has sunk some. That's part of the reason we're having problems with our pipes. They're not being supported, and have sagged and broken under their own weight.

          I do intend to call other cutters, and others in my church are also pursuing other possible solutions.

          I was jus hoping the wizards here would come up with a miracle answer.<G>

          1. Hudson Valley Carpenter | Jul 10, 2007 06:44pm | #18

            I was jus hoping the wizards here would come up with a miracle answer.<G>

            Here ya go.  When the old gas line from the street to my parent's house began leaking, the gas company sent out some guys with special, flexible plastic pipe.  They fed that into the original pipe and pushed it through, all the way to the house, about 100'.  Then they hooked it up.  Just a little bit of hand digging on each end of the line.

            It's a long shot but maybe that same system is available for plumbing drains too.  I couldn't tell you if it is, but it's worth a few calls, I'd say.

          2. User avater
            BillHartmann | Jul 10, 2007 07:08pm | #19

            There are sewer pipe lining systems that could be used if it is just "rotted" CI.But, if it has collapsed or settled it won't help.I wonder what a video inpsection shows..
            .
            A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

          3. Shep | Jul 10, 2007 08:51pm | #20

            One of the first things we did was have a video inspection.

            Unfortunately, it did show that the cast iron had settled considerably in some spots, and collapse in others. I think partly due to the ground settling under the building.

            Another part of the puzzle- the building is actually constructed on hundreds of wood pilings, driven down to solid ground. I can remember hearing the pile driver from my home a mile away when the church was being built.

            Because it was built on poor soil, I guess we're paying now what we saved up front.

          4. vintage1 | Jul 11, 2007 01:28am | #21

            shep,

            Earlier I had posted to you about the hydraulic concrete saw, but reading further see that you may have a problem with the height of the crawl space. 

            for, attached is a photo (sorry for the poor quality) of the saw my guy used.  Very mobile.  If they adjusted the handle I bet it could work in your situation.

            Another thought would be to use a concrete breaking agent such as Dexpan. http://www.archerusa.com/Product_Dexpan.html  I don't think it would be as easy as cutting, but if you could get in there with a roto hammer to drill the holes, It has to be better than trying to swing a sledge in a crawl space.

            Hope this helps.

             

  5. brownbagg | Jul 11, 2007 03:10am | #26

    hire this out.

    saw too big- not your problem

    cant be moved- not your problem

    too much noise- not your problem

    too much dust- not your problem

    your deal is to tell him where to cut, and then I be back in two hours, let him do his job.

    1. Shep | Jul 11, 2007 03:38am | #27

      Thanks for the reply.

      That;s what I'm leaning toward. I want to help my church out, but this is something I have absolutely no experience with. I'm a carpenter. I hate concrete . No offense.

      I think I may call a couple more concrete cutters, and see if I have any luck. Maybe I can find someone with the hydraulic set-up someone described.

      After that, I'll let the plumbers do it their way.

      1. brownbagg | Jul 11, 2007 04:26am | #29

        Maybe I can find someone with the hydraulic set-upif they dont- not your probelmcan you cut on this line
        yes
        I be back in two hour(hint) you really dont want to be there when they cut, trust me on this one.

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

Mortar for Old Masonry

Old masonry may look tough, but the wrong mortar can destroy it—here's how to choose the right mix for lasting repairs.

Featured Video

A Modern California Home Wrapped in Rockwool Insulation for Energy Efficiency and Fire Resistance

The designer and builder of the 2018 Fine Homebuilding House detail why they chose mineral-wool batts and high-density boards for all of their insulation needs.

Related Stories

  • Fire-Resistant Landscaping and Home Design Details
  • A New Approach to Foundations
  • A Closer Look at Smart Water-Leak Detection Systems
  • Guest Suite With a Garden House

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Fine Homebuilding Magazine

  • Issue 332 - July 2025
    • Custom Built-ins With Job-Site Tools
    • Fight House Fires Through Design
    • Making the Move to Multifamily
  • Issue 331 - June 2025
    • A More Resilient Roof
    • Tool Test: You Need a Drywall Sander
    • Ducted vs. Ductless Heat Pumps
  • Issue 330 - April/May 2025
    • Deck Details for Durability
    • FAQs on HPWHs
    • 10 Tips for a Long-Lasting Paint Job
  • Issue 329 - Feb/Mar 2025
    • Smart Foundation for a Small Addition
    • A Kominka Comes West
    • Making Small Kitchens Work
  • Issue 328 - Dec/Jan 2024
    • How a Pro Replaces Columns
    • Passive House 3.0
    • Tool Test: Compact Line Lasers

Fine Home Building

Newsletter Sign-up

  • Fine Homebuilding

    Home building tips, offers, and expert advice in your inbox.

  • Green Building Advisor

    Building science and energy efficiency advice, plus special offers, in your inbox.

  • Old House Journal

    Repair, renovation, and restoration tips, plus special offers, in your inbox.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters

Follow

  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X
  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences
  • About
  • Contact
  • Advertise
  • Careers
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2025 Active Interest Media. All rights reserved.

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

  • Home Group
  • Antique Trader
  • Arts & Crafts Homes
  • Bank Note Reporter
  • Cabin Life
  • Cuisine at Home
  • Fine Gardening
  • Fine Woodworking
  • Green Building Advisor
  • Garden Gate
  • Horticulture
  • Keep Craft Alive
  • Log Home Living
  • Military Trader/Vehicles
  • Numismatic News
  • Numismaster
  • Old Cars Weekly
  • Old House Journal
  • Period Homes
  • Popular Woodworking
  • Script
  • ShopNotes
  • Sports Collectors Digest
  • Threads
  • Timber Home Living
  • Traditional Building
  • Woodsmith
  • World Coin News
  • Writer's Digest
Active Interest Media logo
X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Project Guides
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Online Learning

  • Courses
  • Project Guides
  • Reader Projects
  • Podcast

More

  • FHB Ambassadors
  • FHB House
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • X
  • YouTube
  • instagram
  • facebook
  • pinterest
  • Tiktok

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

Enjoy unlimited access to Fine Homebuilding. Join Now

Already a member? Log in

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in

Privacy Policy Update

We use cookies, pixels, script and other tracking technologies to analyze and improve our service, to improve and personalize content, and for advertising to you. We also share information about your use of our site with third-party social media, advertising and analytics partners. You can view our Privacy Policy here and our Terms of Use here.

Cookies

Analytics

These cookies help us track site metrics to improve our sites and provide a better user experience.

Advertising/Social Media

These cookies are used to serve advertisements aligned with your interests.

Essential

These cookies are required to provide basic functions like page navigation and access to secure areas of the website.

Delete My Data

Delete all cookies and associated data