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Discussion Starter · #1 ·
Hi,


Figured you guys have a lot of experience breaking up concrete slabs so I'm posting this question here.


I need to break open my slab to run some new drain lines and I'm also adding a Mainline Backwater valve. Question is what tool I should rent?


Home Depot has a Bosch Demo hammer or a Bosch Brute jackhammer type of thing (not the full sized one).


Slab is between 2" and 4+" thick. Is the demo hammer adequate for this job?


THanks,


Dan
 

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I think I used the Bosch Demo hammer (it is the smaller version that you can actually lift and use on a wall, for instance). It worked well. Are you going to cut the concrete first? That is what I did. You'll get cleaner lines and the hammer will probably not break up the concrete if you start in the middle of the slab.
 

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Discussion Starter · #3 ·
Yes, the demo hammer is the one thats sort of a hammer drill on steroids. Fits in a case etc... Probably much easier to maneuver than the Brute (hence the name I guess).


Was considering cutting the concrete with the grinder first, but the dust would be horrible. I guess I'm not too concerned with how it looks since eventually it will all be covered up with some sort of subfloor or whatever.
 

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I've used both and if you are doing more than 8-10 ft of trenching I would get the big guy.


With the big guy you can get a lot done with a 1/2 day rental.


If you have any buried plumbing in the area that you want to remain intact you may want to use the smaller version so that you have more control.
 

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I did 110 feet all around the perimeter of my basement with the smaller one and it seemed fine (did it in a day). I haven't used the big one. I did cut with the walk behind concrete cutter (with water attachment) first which made the job much easier/possible.
 

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Discussion Starter · #6 ·
The actual "trenching" I need to do is like 5' or so. Also have to make an opening about 2' x 2' or so for the Mainline valve. The rest is opening up around existing drains and stacks so they can be capped.


I think I'm going to go with the small one since a lot of the work is around existing pipes that I don't really want busted apart.


By the way, half day rental is 4 hours up here in Canada. I suppose thats technically half of an 8 hour day. Going to try and get it done in that period of time since I'm cheap....


Thanks guys.
 

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From what I recall around here you can do a 1/2 day rental in the afternoon keep it overnight and return it when they open in the morning. Also an all day Saturday rental needed to be back when they open Monday morning.
 

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Quote:
Originally Posted by AndreasMergner /forum/post/19601752


I did 110 feet all around the perimeter of my basement with the smaller one and it seemed fine (did it in a day). I haven't used the big one. I did cut with the walk behind concrete cutter (with water attachment) first which made the job much easier/possible.

Did the water keep the dust to a bare minimum?
 

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Yes. Not much dust or any with the water.
 

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Yes you need a concrete saw for clean cuts. A regular circular saw is not going to work.
 

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Discussion Starter · #12 ·
I've seen circular saws used withmasonry blades. Personally, I wouldn't, but it has been done.


I rented the demo hammer and had the job finished in like 2 hours. A bit dusty, but oh well. Worked great.
 

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Quote:
Originally Posted by advertguy2 /forum/post/19855779


I've seen circular saws used withmasonry blades. Personally, I wouldn't, but it has been done.


I rented the demo hammer and had the job finished in like 2 hours. A bit dusty, but oh well. Worked great.

Did you cut the concrete first? I would like to avoid doing that because of the massive amount of dust it would generate. I don't care about how clean it looks. I am putting in a 2'x'2'x1' footer in the middle of my basement.
 

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you dont need to cut first....i have used the big brute one more than i care to remember. after the first hour you should be pretty decent at it and can keep it from wandering.


I found it fairly easy to make 6x6 inch squares in concrete with it.


That being said, you can use a masonary blade on your circular saw...all you need is about a 1/2" deep score line...that should be plenty to "tell" the concrete where to break. but if it doesnt need to be pretty then the brute should offer you enough control.


The best part is it does all the work for you, you dont have to put any muscle into it except to pull it up after you fully penetrate the slab...and that part does become a back killer after a while.
 

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Discussion Starter · #15 ·

Quote:
Originally Posted by longtimelurker /forum/post/19860857


you dont have to put any muscle into it except to pull it up after you fully penetrate the slab...and that part does become a back killer after a while.

Thats the part that killed me. I'm tall (6'8") and I was pretty sore afterwards. Wished they made the bits a good foot longer. Oh well.
 

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I rented the Big Brute last night and it worked great. I didn't have to use a saw first. Thanks for all the advice.
 

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Quote:
Originally Posted by advertguy2 /forum/post/19862476


Thats the part that killed me. I'm tall (6'8") and I was pretty sore afterwards. Wished they made the bits a good foot longer. Oh well.

I hear ya, I am 6'8" too.. I'm about 1/3 way done with my project of adding new drain lines. I own a rotohammer, so I can't justify renting the brute. Unfortunately my slab has the welded steel mesh in it, so it takes longer than I would like.


As for using a circular saw with the diamond blade.. use a 7" grinder instead, they take the same blades, and can handle the dust better( lesson learned after my 7 1/4" dewalt died from dust exposure). I used one such, along with the rotohammer to make window openings last summer
 

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A word of caution to those living in areas with expansive soil...you may have a post tension slab. Please make sure you know what kind of slab you have before punching or cutting holes in it. Not to say you can't cut into a slab with cables in it. You just better know where they are. Cutting a cable will be an expensive fix and could hurt someone if they are standing over it when it breaks.
 
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