# Demolishing Basement Concrete Slab...



## psilva8 (Jan 12, 2012)

CarlsonRower said:


> Hey folks,
> 
> I have a ranch house with an unfinished basement.
> 
> ...


I can't think of many problems but the only thing that comes to mind is this isn't a job for the faint of heart. This is alot of work breaking up the concrete. I would suggest hiring a pro concrete finisher for the floor when you go to pour. Make sure you run conduit under the slab for your data/power receptacles.

You shouldn't have to vac the cement slurry.


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## Daniel Holzman (Mar 10, 2009)

I strongly recommend you wear a NIOSH approved mask when cutting or breaking concrete, the dust can be extremely harmful to you, especially in an enclosed space.


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## CarlsonRower (Dec 5, 2011)

I will be doing the concrete demolition but the new pour I am subing out for sure. I'd rather have one contractor be in change of the new slab pour and the staining process.

Yeah... I calculated the quantity of concrete to be between 15-18 tons... so I know that this work will be VERY labor intensive. 

Is it ok to just let the slurry sit there? I am going to be cutting up the sections this weekend but it will be a few more weeks before I can jackhammer out everything after.


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## <*(((>< (Mar 6, 2009)

Check this out. I haven't used it personally, but know a contractor that swears by it.

Dexpan

And if I were you I would look into hiring a demolition labor company for a bid on removal of the concrete after breaking it up. Some companies have equipment (track elevators for stairs) that can make the job a lot easier. Your BACK told me to suggest that to you!


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## psilva8 (Jan 12, 2012)

CarlsonRower said:


> I will be doing the concrete demolition but the new pour I am subing out for sure. I'd rather have one contractor be in change of the new slab pour and the staining process.
> 
> Yeah... I calculated the quantity of concrete to be between 15-18 tons... so I know that this work will be VERY labor intensive.
> 
> Is it ok to just let the slurry sit there? I am going to be cutting up the sections this weekend but it will be a few more weeks before I can jackhammer out everything after.


I don't see a problem with just leaving the slurry there. It will harden up.

Just make sure you wear a mask, close off any hvac, protect your furnace ( I had drywall dust ruin the exhaust draft motor on my furnace) and close up any openings to upper levels of the house. You will be using water but concrete dust will still be flying around.


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## CarlsonRower (Dec 5, 2011)

Oh wow VERY good call on the furnace... that would have been a silly extra expense for this project...

I like the idea of using the expansion stuff! I think I'll try that before I go nuts with a jack hammer


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## CplDevilDog (Mar 18, 2009)

You'll need a relief joint around the perimeter of the slab before using Dexpan. 2 or 3" removed from the slab, else risk damage to the footing/foundation joint.

Also, get your Radon level checked. If your going to have the slab out may as well get a sub-slab depressurization system in.


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## CarlsonRower (Dec 5, 2011)

Radon was already checked and it is very very low. I forget the number but it was laughable how low it came in at both times. This was done with two separate tests during two different times (one was a home kit and the other was a professional with his own calibrated unit).

If I do my phase one plan of cutting the 950sqft into 2'x2' sections wouldn't that give enough wiggle room for the Dexpan to do it's thing without cracking the foundation?


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## CplDevilDog (Mar 18, 2009)

Dexpan's website may offer some guidance on the width. If you cut it into 2x2 you've essentially done what Dexpan will do. Wasted effort, IMHO.


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## CarlsonRower (Dec 5, 2011)

Hmmm a valid point...

So if I were to use dexpan just cut 3" around the perimeter and the beams to provide the wiggle room?

I'll read the website later tonight as well.


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## robertcdf (Nov 12, 2005)

Be sure to post your progress... I think you'll hate it before long, this is not an easy task nor is it fun. We tear out slabs here and there for decks and they're never ever fun.


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## CarlsonRower (Dec 5, 2011)

Well I am going to call a few places today and compare the price to have guys come out to do the work vs me....

If the price isn't crazy I may just do that... because already we're talking about renting a $70/day cement cutter... $100+ for dexpan... a couple $100 more for a roll away dumpster that can handle 15-18tons of concrete... time will tell and I'll be sure to keep everyone posted!


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## concretemasonry (Oct 10, 2006)

Carlson -

In some types of foundation/basement construction the slab is a critical structural element because it provides lateral resistance to the base of the wall. That carries the real foundation load - the soil it is retaining since the weight of the house is not important as long as there is still a basement wall in place. Many codes require the slab to have at least 3 1/2" of the slab in contact with the wall to guarantee positive lateral support.

I installed interior perforated drains at the base of the footing on a house with a strip footing with an inside floating slab. I had the 4" slab cut 24" out from the wall and left sections to brace the base every 6' or so to maintain stability during the process. The same principal applies to a raft or floating slab that supports the walls because the connection to the slab usually is very unreliable.

Dick


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## CplDevilDog (Mar 18, 2009)

Missed that one. Thanks for keeping us straight.


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## alecmcmahon (Apr 30, 2010)

and might as well add / change your interior weeping system to your sump pit of you dont have one already.


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## CplDevilDog (Mar 18, 2009)

Do I detect a little Scope Creep creeping in here? Well, as long as you're doing this, you may as well go ahead and do that. :laughing:

Its all good, I'm drawing up plans for my bunker before I put my Radon system in.:thumbsup:


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## CplDevilDog (Mar 18, 2009)

By the way, if you're in the Midwest have you considered the value a tornado shelter would add to your home? Something to consider:wink:


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## Dierte (Jan 23, 2011)

i would think twice about in floor electrical. Basements can leak. sump pumps can quit pumping. good luck and take lots of pics.


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## Doorman54 (Feb 22, 2012)

Look into a dry concrete saw. 
We have a Hilti brand one at work. Comes with a HEPA vac and about 12' of hose. 

It's a bit slower then a gas saw but definitely cleaner!!!

I've used it a few times at work (loop detectors) and at home to cut my drain for my master suite shower. 

You'll need at least a 20amp circuit for the saw and a separate 15 for the vac. 
Earplugs a must as well.


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## concretemasonry (Oct 10, 2006)

The guy that sawed mine used a gas powered wet saw and we just closed the door and put a fan in the window for most of the dust since were knew we would have a lot of other clean-up later. When we put in the sump and hit water before installing the drain tile, I knew we had the right solution to reduce the water leakage and pressure.

Just myself, my 12 year old son and his buddies when available.

Dick


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## CarlsonRower (Dec 5, 2011)

Just wanted to give an update on this post for those interested:

After calling a few places I decided to just contract out the work. The price of the demo ended up being $2000 for full removal and disposal of the 900-950sqft of concrete along with a bit of whats below that (about an inch so that I don't lose a lot of head room when i put in foam etc).

It seemed like just to rent a roll away that would take concrete and to rent the equipment (jackhammer, saw etc) would start getting me close to $1000.... main reason I said screw it and hired it out!

I am creating a new post regarding the installation of the slab, foam, geothermal system etc.

Thanks again for all the input guys!


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