Conference 7.286::home_work

    I saw a demonstration of a masonry saw on "This Old House" on PBS.
    Cut right through a foundation wall in minutes.
    
    Marty

    .1
    Was that the cement block wall in Florida? That may be easier than
    cured solid cement. A friend of mine said the saws worked good,
    but he was using it on new cement that wasn't totally hardened.
    I'd like to know how well they work too on old foundation, I 
    want to put a door out my backyard and have to cut the foundation
    about 3 feet wide by 1 1/2 high. I started drilling holes, have
    2 holes all the way thru, 8 inches, using a half inch masonary
    bit, but the chuck on the drill I borrowed from dad is pretty
    warn and the bit tends to slip and wear out inside the chuck.
    I guess I should buy him a new chuck for his drill. (not your 
    cheapo 29.95 home drill but a miller falls heavy duty......)
    
    Jean

The saw you are refering to that looks like a cross between a
chain saw and a circular saw is just that, a chain saw with a
different bar and a belt drive. The one we have at the fire 
department is known as a K12 (thats the model number). It 
basically is a contractors saw and while I have never cut
a concrete wall with it, cement blocks cut real nice, real
clean. If I were to consider a similar project, thats what I
would use. I will repeat that I have never tried it and disclaim
any responsibility.
   The reponsibility I am disclaiming is from reasons of safety.
That blade is moving FAST and unless the saw has a brake on it
take a while to slow down. Using that saw is one thing you do with
your own personal safety in mind first. You dont want to use it
unless you are 100% awake, sober and very sure of your footing
and have good lighting. It is not a tool to use with a bunch of
onlookers. A second person to steady you and act as a safety 
observer is a must. Gloves, goggles, and long sleves to protect you
from flying particles is important and cutting concrete you
should have a dust mask. If you hit metal, you will see lots
of sparks. A water hose is a real good idea.
   I am not saying advoid the tool. It works good, cuts good
clean lines and I would definatly use one over going the drill
routine. You just have to give the tool all the respect that it
deserves


Bill

    A saw for cured concrete is a little more robust than a K12.
    Years ago I used up multiple blades of one of those tools
    trying to go through a concrete wall, even though it went
    through blocks like butter.
    
    Last week I asked a company that cuts holes in concrete walls
    for a bid to cut a 2 x 6 foot hole in an 8 inch foundation wall
    and they quoted me $600 - $1000 based on how long it would take.
    (They said from 3 to 6 hours!)
    
    If anyone knows an easier DYI way, let me know.

    I am looking at the same kind of project and due to time constraints
    and having too many other projects to do, I am willing to hire a
    concrete sawing company for $350 (their minimum charge).  This will
    cut me a door sized opening in the foundation, no muss no fuss.

    I've only one aversion to hiring contractors - I can't live glued
    to the telephone, and can never seem to make contact with them.
    My experience with electricians a few months back is an example
    - I called a half dozen of them - NONE called back.
    
    I'm convinced from the last 'n' responses that cutting 15 year old
    solid concrete is no picnic. If it was trivial, after all, it wouldn't
    cost $1000 for 6 hour's worth. I suspect some of that charge is
    for diamond studded saw blades.
    
    Thanks for the tips and if anyone knows any concrete cutters that
    have the courtesy to return phone calls... please pass their names
    on!

    -Scott
    

    I'll let you know the results in about 3 weeks.  That's when the
    guys are supposed to come and cut the hole.

    I talked to Concrete Coring in Nashua and I believe they quoted
    $25/lineal foot to cut a foundation.  I was asking about 3 cuts
    with a total distance of 12 feet (12 ft x $25/ft = $300).  Their
    minimum charge was $350 they said.  The opening would be 5 feet
    high and 2 feet wide.  I already have a window type opening into
    the crawl space and want to make it into a door.  Concrete Coring
    is a national franchise and they may have an outlet in your area.
    
    BB

    I just had a doorway cut out of my 15 year old concrete foundation
    wall. The work was done by Frank (and wife Karen) P. Mabardy
    (Mah-BAR-dee, I believe) in Southboro, MA @460-9742. These folks are
    not in the Yellow Pages, so I asked their OK for this referral.       
    
    In addition to promptly and conscientiously returning telephone calls
    (a pet pieve of mine!), he was very punctual showing up for the initial
    estimate, as well as the morning they did the work. He explained what
    he was going to do, side effects (overcutting into the floor and sides
    due to the size of the blade being used). The price was reasonable
    - $300 minimum. He suggested other work I might want so that I got
    the full $300 worth. With the exception of a 600 pound monolith
    of concrete I had to break up, they left the place as neat as could
    reasonably be expected, helped flush the water/mud out of the room,
    and were just helpful in general. (BTW, the mud is the result of
    extant dirt + water used to keep the concrete dust down - the guy
    wasn't responsible for making mud in this room!)
        
    I dunno whether he'd travel to Nashua (doubt it...), but
    Worcester/Middlesex county, Mass homeowners with concrete-cutting
    needs should consider Mabardy for the work. Please tell him I referred
    you.
    
    -Scott
    

    Now that the new door is in, I have to fill in the old doorway with
    concrete (another new experience!). I've calculated a mere 6cf of
    concrete, and plan to use Redi-Mix.
    
    I am looking for advice on concrete forms - this is a confined,
    vertical area. There's no way to support it on the inside:
    
    
                            +--------------------------+
                            |                          |
                            |                          |
                            |                          |
                            |    Room=14'x16'          |
                            |    unfinished              Doorway=40x45x10.5"
                            |
    			    |                          |
                            |      <<== 14' ==>>       |
                            +--------------------------+
  
    Bracing on the outside is difficult (it's kinda in a trench), but
    not impossible.
    
    What I figured I'd do is wire the pieces together at several points:
    what kind of wire do I use??
    
    I survived the experience of removing the old door and getting the
    new doorway cut... I can't let lack of experience here stop me!
    Got some experienced concrete workers out there to lend advice?

    
    -Scott
    

    Brace AND Tie!!!  Figuring concrete is about 150 lbs/cubic foot,
    wet, even your 6 cubic feet is going to weigh in the neighborhood
    of 900 pounds.  You most definitely do NOT want the form to break
    or even bend.  Put braces across the entire room to the opposite
    wall inside; put a couple of boards down the side of the trench
    and wedge short lengths of 2x4 between them and the form on that
    side.  Make it at least twice as strong as you possibly think it
    would need to be, and it might come close to being strong enough.
    
    Tying with wire is a good idea - frequently done.  Nowadays they
    use specially made wire tires, but in the old days they'd use
    #9 steel wire, going through holes in the form, wrapped around a
    2x2 on the outside of the form, and the ends twisted together, then 
    the whole business tightened by putting a large spike or screwdriver 
    between the two strands on the inside and twisting them together.
    
    Since I assume you care at least a little about the appearance of
    the finished wall, at least on the inside, think about investing
    in a couple sheets of 3/4" CD plywood for the forms, inside and
    outside, with probably about 4 2x4 crosspieces on each side for
    stiffening, to wrap the wires around, and to nail the braces to.
    A coat of varnish on the plywood will let it peel off real nice
    and keep it from getting too grunged up so you can use it for something
    else later.
    
    Most pressure is at the bottom, of course; tie and brace that REAL
    well or you'll have concrete oozing out around the edges.
    
    Wirebrush the side of the hole and dampen the concrete before you
    pour in the new stuff; if you could put in some sort of anchor bolts
    on the sides for the new concrete to lock to,it would probably be
    a good idea.  
    
    Steve

    
    Ever watch a house foundation poured? The only outside bracing they
    use is to hold the forms plumb and level - everything else is done
    by ties thru the concrete.
        
    For forms, I would go with the two sheets of 3/4 ply, with 2x4 ribs
    on the outside of each sheet, at the top and bottom and otherwise
    spaced about 12'' O.C. The ribs should be attached like so
    
                                  ~   ~
                                  |   |
                               XXX|   |XXX
                                  |   |
                                  |   |
                               XXX|   |XXX
                                  |   |
                                  ~   ~
    
    so that their strength goes into preventing horizontal bulges.
    Place one form against the outside of the wall, one against the
    inside, insert ties (through the ribs, at the edges of the pour
    and every 12'', so that the ties are about a foot apart in all
    directions), and tighten so that the forms are snug against the
    existing wall and just begin to show a slight bow toward each other
    (when you sight along the top edge of the forms).

    (-: Alternative: glue the plug you cut out of the other foundation wall
    into the old opening :-)

    I had a foundation poured for an addition and they used the forms
    with the 3/8" metal ties going through them every 2' or so.  
    
    It is VERY important that you seal the outside thoroughly if the
    foundation will be below grade!  The contractor applied some tar,
    we did some more, but the ties are starting to rust and water comes
    through some of them like it was a hole drilled straight through.
    
    I have no idea what would be sufficient waterproofing, but all I
    can do is drill them out and plug the holes with hydraulic cement. 
    
    -joet

    Drill the ties out of the walls?  Good luck!  I have
    those ties too.  I used roofing cement in addition to
    regular foundation waterproofing.  They still rusted
    and leaked a little.  Many of them can be moved inside
    the wall so I know it's not a watertight seal.
    

    Re: .12 - it's not that the thought hadn't occured to me (to put
    the cut "plug" into the existing whole. There was the matter of
    the 600-some-odd pounds the slab weighed, not to mention holding
    it in place. Getting the crane in would be the hard part :-)
    
    In fact, I intend to re-use the sill-piece that I cut for the new
    doorway to restore the piece now "missing" from the old. I broke the
    slab up with a rented jackhammer (a DIY experience highly recommended -
    once - for anybody that's never done it!). The remains are filling the
    hole that led to the soon-to-be-gone entranceway. 
                                                       
    It looks from your recommendations that I need to get some sturdier
    plywood for this endeavor. At $20/sheet, I do not look forward to this,
    but no matter it has to be cheaper than hiring somebody to pour a
    piddly 6cf! 
    
    The first response mentioned a specific type of wire - what should
    I use? Do hdwe stores sell it, or concrete places (like Kane in
    Hudson).
               
    Anybody got concrete-form-materials they'd like to lend/rent?
    
    -Scott
    

    You might try a fencing supply place and see what kind of wire they
    may have.  Or possibly a place like Lancaster Grain & Supply in
    Lancaster, if you're anywhere near there.  Basically what you want
    is a really heavy-gauge steel wire, #8 or #9, probably.  I think
    the ready-made form ties are for a specific wall and form thickness,
    and if you don't happen to match up you're out of luck, but I may
    be wrong on that and you could no doubt put blocks of the appropriate
    thickness on the outside of the form if need be to make them line
    up.  However, just plain wire will probably be simpler for the job
    you're doing.
    

You could probably avoid the rusting problem by using bronze welding rod.
It certainly would cost more than steel but then again you would not be
using all that much.  It would seem to me that there should be some method
of joining the new piece to the old wall like maybe drilling some large
holes in the old wall and inserting rods which would extend into the new.
Or I suppose if you made the holes large enough that the new concrete would
flow into the hole and you would not need the rod.  I would imagine the
better way would be if the old opening would have some vertical grooves cut
into it so that the new would be locked into the old wall (after it dried).


Rod approach:

*********		*********
old	*    new	*
	*		*
rod =========      ==========
	*		*
	*		*
    =========      ==========
	*		*
	*		*
    =========      ==========
	*		*
	*		*
    =========      ==========
	*****************


Groove approach:  (top view)

*********		*********
	*		*
      ***		***
      *			  *
      ***		***
	*		*
*********		*********

    I neglected to mention (or perhaps my terminal-art skills equal
    some of my DIY skills :-) - the hole I'm filling is indeed notched
    as in the 2nd drawing in .17. I imagine that this will help some
    with waterproofing, and the "plug" certainly ain't gunna fall out
    (assuming that I keep it from oozing out...)
    
    
	*********		*********
		*		*
	      ***		***
	      *	<=nails sticking=>*
	      ***  out of groove***
	       	*     too       *
	*********		*********       
    
    -Scott
    

    The ties used for forms are about 1/4" rod with the equivalent of
    several 'heads' on them. They are placed through the holes in the
    forms and steel wedges with slots in them (no way can I draw this
    with terminal art). The wedge drives up against the head and tightens
    the thing. Most have a large washer like piece that winds up aginst
    the inside edge of the form. to help seal the hole.
    
    The ties can be had from any concrete supply store. The wedges are
    part of the tool kit of a form builder and I suspect cost a bit
    to much to buy for one time use. I suspect wood wedges would work
    for one time use.
    

    Let's not make this to hard: go to a large supply house and get
    threaded rod,washers and nuts to fit. It should be at least 3/8"
    dia. Make sure it will span the wall, the plywood and the 2x4 braces
    The 2x4 should be spaced every 12" to keep the mud in the form with
    the first one as close to the bottom as you can place it. Be fore
    you tighten the thread rods, stuff about one inch of fiberglass
    insulation in the vertical sides from top to bottom to compensate
    for the uneven wall of the old foundation. Two additional points
    the 2x4's must extend beyond the opening and actually clamp the
    form to the existing foundation and if your opening is less than
    20" get the lumber yard to ripp a 4x8' sheet into (2) 2x8' pieces.
    Coating the forma on the inside with a thin coat of grease will
    allow for easy removal. Good luck. 

    
    Back to cutting concrete, I finally work on my wall and completed
    it. I had only a small section to cut out, 1 foot high and 38 inches
    wide, so figured I could do it with a little work. As I said in
    .2 I was using a hammer drill and half inch bits to drill holes
    thru the concrete. Well this wasn't working to well even with a
    new chuck on the drills, took too long.... and wore out the bits.
    I figured I would check out the rental stores for either a saw as
    discussed earlier or a jack hammer type drill. I chose what they
    called a rotary hammer drill, that used 3/4 inch bits and also
    worked as a jackhammer with a chisel bit. This worked pretty good,
    went thru the foundation in a few minutes, and I made about 16 holes
    across the bottom and about 5 on each side, and a couple down from
    the top. Then did some chiseling of the sides, and wacks with a
    sledge hammer and got the job done!	I probably spent an hour and
    half on Saturday and  3 or 4 hours Sunday, but I took alot of 
    breaks so it's hard to say how long it really took! 
    Someone to help hold the drill would have made things faster as
    it was pretty tiring. Also had lots of torque! A good work out on
    the forearms and upper body! My Arms are sore today...
    Anything much bigger than this, I would probably have some come
    and cut it with a saw... , but I would do this again with the rental
    hammer drill. Oh yeah, it's $32 a day, and I picked it up Saturday
    afternoon around 3:00 and had to have it back for Monday morning.
    Closed Sundays... (Gosselin's Rental Store, Manchester N.H.)
    Jean
    .
    

    I too had to cut some concrete this past summer.
    
    I wanted to cut two(2) holes 45" x 30" for windows, and a 40" opening
    for a doorway. I started with a rotary hammer which I rented to
    $50 a day with bits.
    
    At the end of the day, I decided to look for someone else to do
    it.
    
    I found a professional concrete cutter in Bolton Ma. who came out
    with an Ingersal Rand 185CF compressor and air driven concrete saw with
    a 30" diamond tip blade and two workers. They cut all three holes,
    AND broke up the concrete remains into small easy to carry chunks.
    
    They did it all in about 4 hours, and it cost me $910.
    
    Their minimum bill is $450. The door alone would have been about
    the same.

    Re. .9 referral of Frank (and wife Karen) P. Mabardy
                       Southboro Mass. 460-9742
    
    Thanks to this notes file and Scott Blessley I had Frank cut a door way
    between my new addition and house. He was everything that was stated
    earlier and he did and exellent job. Prompt? I called their office
    around 10 AM, he returned my call before noon, and he did the job the
    NEXT DAY! 
    
    His prices are a bit more this year though, $350 to cut the door
    way, $50 to drop the slab, and $50 to break it up. He did give me
    a break ($400 instead of $450) because he did my next door neighbor's
    the same day. 

    Charly

    
    Here's another song of praise for Frank Mabardy. we're putting an
    on our house and needed an opening cut in our old foundation wall.
    After I read this note  my husband called him and the rest is as
    told in .23.  He came to do the job the day after our call. He was
    prompt, pleasant and did an excellent job. He charged $350 for the
    cut, $50 to drop and $50 to break up the slab (wellll worth those
    two extra $50's.)   
    
    He was real pleased to hear the recommendation was through Digital.
    Said he gets most of his work by word of mouth. His assistant's wife also
    works for DEC so the good vibes were gushing all over.
                                    
    Again, thanks for the info and glad it's possible to pass along
    positive recommendations.
    
    Kathy

    
    Re: .9  .23   .24
    
    I received a mail message from Michelle Rowe whose husband works
    for Fred Marbardy. The reason for the note is the above responses
    have all incorrectly called Fred...Frank.  .9 and .23 also incorrectly
    called Fred's wife Nancy....Karen.    
    
    Apparently Fred and Nancy received copies of .9 .23 .24 in the mail.
    There was no cover letter of explanation, just copies of the three
    notes.  Fred and Nancy are happy to get the referrals, just want
    their correct names to be used.
    
    So to clarify:  FP Concrete Core Drilling and Sawing is FRED and
    NANCY Mabardy.   NOT  Frank and Karen.
    
    I find it weird the DEC person that sent the 3 notes to the Mabardys 
    and gave no explanation as to why!
     
 

    I would like to recommend F.P. Mabardy for Concrete Core Drilling
    and Sawing.  The phone number to call is 460-9742.
    
    

Well it's finally time to cut that doorway and I just can't see giving someone
$350 for something I might be able to do myself.  So, I called up the good ol'
rental store and they told me that have a gas powered concrete saw for $35
a day that will cut a hole 5" deep, so that means one cut on each side of the
wall.  Anyhow, if it doesn't work out, it will certainly be an experience.

I figure even if it takes the whole day I'll be ahead of the game.  But then 
again, from my perspective, DIY isn't just saving money, it's doing different 
things and I figure this certainly fits the bill.

Has anybody actually tried this?  Most of the preceeding notes talked about 
people who hired someone or used rotarty hammers for smaller opening.

-mark

    I once used a circular saw and a carborundum masonry blade to cut
    two 1/2" grooves in a concrete floor in order to chisel out a nice
    neat channel to bury some tubing (yeah for an oil burner, and yeah,
    I know about the dangers of running it in concrete, but I live
    in NY and I don't own the house anymore...).
    
    After doing that, I decided that cutting concrete was a task that
    you cannot pay someone enough money to do.  Or, conversely stated,
    it was so unpleasant that I couldn't care how much money I can save
    by doing it myself.  I'll gladly pay someone to do it in the future.
    
    If you do insist on DIY, (and if a concrete cutter operates on the
    same principle as my "method") prepare for an incredible amount
    of dust and wear a good respirator.
    
    Actually, I have seen electricians use some kind of doodad to bore
    holes up to 6" in diameter through reinforced concrete floors (in
    a chemical plant).  Whatever they were using, it did not seem to
    raise much dust.  In fact, they were using it in a computer room.

    /Al
    

    Don't do it yourself.  I was going to and learned that it would
    fill the house with concrete dust - pros use a water saw, and you'd
    go through about a hundred blades at about $5 apiece.   You really
    need a diamond blade and as they cost about $250, you can't rent
    them from a rental store.
    
    I had to 'move' my bulkhead door in my foundation due to where we
    wanted the garage and porch.  I drill a series of holes about 2"
    apart about 2-4" deep and used plugs and feathers borrowed from
    a granite quarry.  Even if you have to buy the plugs and feathers
    you still come out ahead.  You could probably get away with a hole
    every 4".  The drill cost me $35 a day (1 day).
    
    Thing broke right down the line.  When the backhoe came in to dig
    the foundation we just pulled it away.

>You really
>need a diamond blade and as they cost about $250, you can't rent
>them from a rental store.
    
Not true.  I just double checked at the rental place and their saws DO have
diamond blades.  However, I think the first place I had called (the $35 special)
didn't know too much on the subject.  The guy I just spoke to this morning said
their saw costs around $40 BUT you have to pay for ware on the blade measured
in thousandths of an inch!  He estimated that it would cost around $100 for the
saw and blade.  He also pointed out that could be high and it could be low!

THEN he went on to describe in detail how the saw will only cut to a depth of 
around 3-1/2" (on each side) so that one then needs to chisel out he rest. To
do that he can rent me a rotary hammer for another $50!

To top it off, he said to budget around 1-1/2 days!!!  That struck a nerve.  I
like to try new things and save some money while I'm at it, but when I've got
wiring, plumbing, insulating and all that other stuff to do, I can't afford to
blow a full weekend on some stupid wall.  Then again...

-mark

    
      PLEASE TAKE NOTE>>>>
    
    I just got finished cutting two "trenches" in my cellar floor. 
    One for a shower drain and the other for the pedestal sink.  The
    saw was $35 a day and each blade was $12 dollars.  I cut a six
    foot and a three foot trench and used two blades (actually one was
    hardly used).  This was in the basement of a three story townhouse
    condo.  When I finished the two floors upstairs looked like a lunar
    landscape, you could see NO COLOR anywhere.  I paid $368 for a cleaning
    crew to do a so called "professional" job getting rid of the dust.
    In hsort they didn't.
    
     A professional concrete sawing company uses a water saw, no dust,
    just clean up the wet mess.  And believe me, it will be worth every
    penny!!!!!

    remember  that cutting a FLOOR is significantly EASIER than cutting
    a vertical WALL as the diamond saw weighs 35-65 pounds. When using
    a diamond blade, the saw musty not twist AT ALL otherwise the blade
    will break. Yes, Taylor rental DOES rent diamond blades. They
    charge $5-10 per thousandth, and you can count on .0010 (that 10
    thousandths) for a few feet of 3" cutting.

    My recommendation: DO NOT CUT WALLS WITH A SAW UNDER ANY CIRCUMSTANCES
    UNLESS YOU:
    
    	1. Can build a jig to hold the saw vertically
    
    	2. Can use lotsa water in the area.
    
    	3. MUST have a basically SMOOTH CUT
    
    	4. Don't are if it costs alot
    
    
    USE THE ROTARY IMPACT HAMMERS WHICH ARE ACTUALLY QUITE EASY. I DRILLED
    THROUGH A 12" THICK WALL FOR A TOTAL OF 9 LINEAR FEET IN ONE AFTERNOON!
    ALL FOR ABOUT $50. I USED A 1" BIT WITH THE CHISEL ATTACHMENTS.
    LOOKS REAL NICE.
    
    Mark
    

Charly

would you mind posting the name of the person who did your job in the 
contarctors referral note?  I think I may want to give this guy a call.

I'm still confused over why I'd want to pay someone to drop the wall.  I've got
a 16lb sledge hammer and don't why I couldn't at least handle that part of it
myself.  As far as getting rid of it, I simply thought I'd break it up where it
lays and cover it over with the new floor.  I know breaking concrete ain't fun,
but I figure I've got to contribute something to the effort.

-mark

Well, I finally broke down and called a pro, I can't remember his name and I'm
too lazy to go downstairs and look but he's the guy from Southboro.  We had an
interesting chat.

He said the job will take about 4 hours and cost $400!!!  He also said his saw
costs $25K and the blade is another $3K.  He said dropping it isn't really a
problem since I'll be cutting out a window.  Apparently the charge relates to
the problems of removing a solid sectin of wall that goes floor to ceiling - no
way for it to pivit.

The slab will weigh around 1200 lbs!

He suggested digging a hole in the new basement to let the slab drop into, but I
don't think that will work since I have a drain pipe running the length of it 
AND I'm not even sure if I can get the dirt out - I don't want to raise the
grade. He said he'd break it up for another $50 and I said I'll do it myself
since I have my own sledge hammer.  He then told me 10" concrete is extremely
difficult to break and the sledge would simply bounce off it.  So... 

-mark

I couldn't believe it.  Today my wife called to tell me my father-in-law was
cutting a hole in our wall.  Naturally I ran home over lunch and sure enough
he was chipping away at my wall with a hammer and chisel!  Belive it or not,
he's gradually breaking through and it looks like I'll save the $400 after
all.

I guess when you're 78 and don't have a whole lot to do, you can spend multiple
days (and I'm sure it'll take him that), beating up on a wall.

-mark

    Come on.  At least take the guy out for dinner and only save $350.
    
    Stan

    RE: .36
    
    I know I wouldn't let *MY* 78 year old father try to hammer and chisel
    through a cement wall!  I hope this ambitious person is in good
    health!  Sometimes new fangled ways are better, though he might
    not think so.
    
    Phil
    
    P.S.  Definitely let us know how it turns out!

Before anyone gets the wrong idea, let me quickly say that my father-in-laws
head is harder than my foundation!  I told him I wanted to hire someone but
he'll not listen to me.  He just comes over every day and starts pounding away.
If he's not pounding a chisel he's outside swinging a sledge hammer.

-mark

Well, the deed is done.  My father-in-law decided after a couple of days that
it was too much work to do by hand.  The only thing that amazed me was that it
took him that long to figure it out.  Unfortunately by this time I had already 
planned on getting someone in to do the floor in a few days.

So, I rented a rotart hammer.  Wonderful tool (it costs around $55 a day).
In one position it's a jack hammer and in the other it's a hammer drill.  You 
can drill a 1" hole through a 10" wall in a couple of minutes.  Only problem 
is I had to drill around 100 of them!

Therefore, all you need to do is drill the holes (several hours of work) and 
then chisel out a slot on either side.  Since it is 10" thick, the slot needs
to be at least 5" wide to get that deep!.

Now for the fun part, getting the slab out.  To this I removed it in several
pieces by cutting a horizonal line and wacking the top with a sledge hammer
while my father-in-law pulled with a rope to force it where we wanted it to go.

The real killer was breaking it off at the floor since we had to drill 
horizontal down low AND because I was at a near state of exhaustion by then.

Anyhow, now that it's done it looks pretty good if I do say so myself.  I plan
to run some strips of wood up the sides to cover the jagged edges someday, but
for now I've got no problems with the way it looks AND I saved a cool $400.

The only real negative here is that it's HARD WORK!  I consider myself in 
reasonably good shape and I worked mu ass off from 9-5:30 with a 10 minute 
lunch break and put in about another hour the next morning.  Actually, about
every 1/2 hour I'd take a 5 minute break and my father-in-law would do some
drilling and jack hammering.  If I was all alone, I'm sure it would have added
multiple hours to the task.   As for a mess, it wasn't TOO bad, but that sucker
does kick up a fair amount of local dust so if you choose to do it be sure to
wear a dust mask and get some goggles. 

As for breaking up the slab goes, I can't really say.  My father-in-law did all
that with my 16lb sledge hammer while I was drilling.  It took him around an
hour or so. 

Finally, there's the pile of rubble.  It's BIG!

-mark

    This saga has been quiet for a while.  Looks like we have noters
    who have gone all possible routes, so...
    
    I wanna put in a 5' slider in a basement with a concrete half-wall.
    The halfwall is about 3' high.  So I need two 3' vertical cuts and
    about a 5'6" horizontal cut right at the floor.
    
    The bad news is I think it's 12" thick.
    The good news is it's less than a year old.
    The bad news is I'm very low on funds.
    The good news is I wouldn't think of trying a saw.
    
    1) Do I have half a prayer of doing this with a rotary hammer and
    chisel?  The cut need not be clean.
    
    2) If concrete weighs 150 lb/cu ft, the cut piece will weigh 2250
    lbs.  Uh, I guess I dont just push it over after making the cuts,
    huh?   Are we talking multiple 3' vertical cuts to make the pieces
    manageable?
    
    Jim

    ROtary impact will do it fine. 1 day or less! Piece of cake. Use
    a 1" bit, and get the biggest unit they have at the rental place.
    Should cost about $35 or so a day.
    
    One note:  If you need 5'-6" horiz opening, cut about 2" on each
    side larger (Total horiz of 5'-10"). That will give you a
    MINIMUM of 5'-6" of clear opening EVEN AFTER accounting for the jagged
    edges you will get.  (I did the same thing and actually finished
    the jagged egdes by pouring a cement 'CAP' over it, much like a
    cap on a tooth.  Looks and functions REAL NICE.)

It's certainly doable but I'm not sure I'd call it a piece of cake.  I cut a
doorway (full height) in a full basement in a single day (I had an extra hours
worth of work to do the next day) and I busted my ASS!

I think you'll find that after making the vertical custs you may have to make
one or two more since I doubt if you'll be able to push over a single slab
that size.

One last comment, be prepared to bust your ass some more breaking up the slab!
Finally, you get the joy of figuring out what to do with the mess.

oops, almost forgot!  We're talking at LEAST as must dust as sanding jointing
compound so say good night to your basement.

-mark

    If you're going to use a concrete cutter/saw:

    remember that the concrete cutter is probably going to be something
    like a very heavy-duty chainsaw, and you'll be blowing the exhaust
    into your cellar.
    
    Use a diamond blade.  I'm told (after using abrasive blades) that the
    diamond blade is faster, neater, CLEANER.  I cut a 5' x 4" x 4" trough
    out of my cellar slab, and made a hell of a mess going through two
    abrasive blades. The saw was $40, and the blades cost $13 apiece.  A
    diamond blade was quoted as $14, plus $2.50 per millimeter of
    wear.  (The diamond blade costs $400 new.)
    
    Be careful of kickback.  Wear goggles.  Wear ear protection.  Wear
    a mask.  Put exhaust fans in windows.  Open all the windows.  Have
    a bucket of water and a mop handy.  (You'll still make a mess!)
    Make sure you're not tired.

    (Just as I started to notice how tired I was getting, and said to
    myself, "This could get dangerous," the saw caught on the edge
    of the trough, and kicked up to about shoulder height.)

    
    re .41 - have you tried it yet ? 
    
    re .42? - how much dust does the rotary hammer kick up ? 

    What's the best way to undercut a crack, for the purposes of patching
    it.  Is a rotary hammer with a chisel bit overkill (the crack is about
    4 feet long)?  Is an ordinary hammer and chisel underkill?  What sort
    of chisel would be appropriate?  (Sears had a wide brick chisel, but I
    don't know whether that's suitable, and I'd hate to have to do it with
    a 1 inch cold chisel.)
    
       Gary

    I'd use a rotary impact hammer, with a 1" carbine point and the chisel
    for cleaning it up.
    
    

    
    I have a small old (75 years) wall that comes half way up the room,
    I would like to remove it.  It is about three feet high and five feet
    long.  It is about three inches thick and has wire mesh on one side.
    
    Suggestions?
    
    Thanks!
    
    
    			
                   
    
    
    
    
    

    re: .48
    
    This is like a room divider or something?  
    

    
    
    	Well, actually this is a Diner from the 1930's.  It was moved
    	lakeside to be used a a Summer camp.  They later built a house
    	around it, foundation and all.  The kitchen/dining room is the
    	diner still, rounded roof and all.  It has a concrete floor and
    	the side walls are concrete half way up.  One end is wood (towards 
    	the front of the house) and the other is concrete with an opening for
    	a door.  There was a wall there which went between the kitchen sink
    	area and the diner, which I removed.  What is left it the concrete.
	I was going to build a cabinet/counter space over it but it is too 
    	high.  I considered cutting it down a few inches but the *right*
    	way would be to remove it.....
    
    	So, that's where I am right now.  I can't afford a lot of money so
    	I was considering some sort of tool rental.  A sledge hammer may
    	even work. 
    
    	/ab
    

Funky!

    they have a saw you can rent for about
    $40-$50 buck  a day.  Blade extra......
    
    

    You might be able to bash it down with a sledgehammer, depending on
    how robust you are and how robust the wall is.  3" of concrete
    should crack pretty easily, but the mesh will complicate the process
    considerably because the concrete will hang together on the mesh and
    not fall apart after it breaks.  If the mesh is really on one side,
    you may be able to knock the wall in that direction and bend everything
    over, then use some bolt cutters to cut the wires.

    
    
        Thanks for the advice.  I have a feeling now that I'm into this place
        my name will be appearing in this file more often.
    
        The mesh is on one side.  I am going to try the sledge hammer
        approach first.  I am *robust* enough (a little too) to swing it.
    
        I'll post the results.
    
        /ab
    
                 

You could also try one of those diamond circular saw blades (Harbor Freight,
~$60) and an old circular saw.  Esp. if you have some more concrete/stone
cutting in the future.  Lotsa dust.

-Mike

    Rent a small electric jackhammer. Most tool rental places should have
    several sizes/styles.
    
    Paul
    

    
    
    	I went to Spag's yesterday and bought a 12 lb. sledge hammer.
    	It did the job well.  The wire mesh came off with it.  
    
    	thanks for all the advice!
    
    	/andy
    

    
    	I'm looking for someone to cut a 12" hole through 8" of concrete.
    
    	Anyone know of someone or have this done before?
    
    	Thanks....

    	A 12" round or square hole ?
    
    	Ray

    
    	Round, square... whatever.  I need to run an eight inch heating
    	duct through it.  I don't want to rent anything or spend a day
    	doing this. I'd rather hire someone and work on another room...
    
	/acb

    	The reason I ask is that it is relatively easy to take a masonary
    saw and cut a hole in the wall compared to trying to drill a round hole
    that size. If you don't want to do it yourself, none of this matters anyway.
    You may want to at least include your general location if your looking
    for a contractor reference though.
    
    	Ray

    Re .58:
    
    Look in the Yellow Pages under Concrete Blasting, Breaking, Cutting
    & Sawing - you can find several companies who do cutting & coring.
    It may be more expensive than you think - I received some estimates
    of a few hundred dollars to cut a hole of about that size through
    a 12" block wall.
    
    A much less and almost as good alternative is to rent a REAL hammer
    drill (NOT the Joe Homeowner style) and concrete bits from a rental
    store.  These babies can drill a 1-inch hole through an 8" poured
    wall in under a minute.  Draw lines for the outline of your opening,
    drill holes spaced about an inch apart, and break through the rest
    with a cold chisel.

    
    	Thanks,
    
    	I had a friend who had an eight inch hole cut in his poured wall
    	for $50. (Each, had two done).  I may as well check on the rental
    	of a *real* hammer drill.  Is there a blade that I could put on
    	my sawsall that would handle the job? 
    
    	/acb

I had a couple holes cut in my foundation for my addition.
The 2 places in the Nashua area wanted around $20/ linear foot of cut
with a $300 minimum.  For a 4x4' hole and a 1x1' hole,  it took about
2 hours in setup, 15 minutes of cutting and 30 minutes to patch the
wire to the water pump that they cut through. (They needed water to finish!)

It was worth it for a job this size.

Garry

>     	Is there a blade that I could put on
>     	my sawsall that would handle the job? 

	I hope you're joking ..... :-)

    re:64
    
    	If you're referring to the masonary blade that I mentioned, this
    was for a circular saw. They cost about $3 at Home Depot or HQ, for a
    7.5" blade.
    
    	I've used these to make clean cuts in patio/cement block and ceramic 
    tile with great success. It does eat the blades as you use them. If you 
    were going to rent a hammer drill and do the outline, you may be able to 
    cut through what's left with one of these. For that sized hole, I'd pick 
    up at least a couple of blades.
    
    	The problem with just using the blade is that it can't cut all the 
    way through from one side. Matter of fact, you won't be able to go all 
    the way through coming from each side, but it may be close enough where 
    you could hit it out with a hammer. Even if you could go all the way 
    through from both sides, you'd want to drill the corner holes to see 
    where to cut with the saw.
    
    	Ray

    Another tip for using masonry blades in a circular saw.
    Get a bit of oil-tempered hardboard and attach it to the shoe of the
    saw with double-sided carpet tape.  It stops the shoe getting
    scratched & chewed up by the  concrete.  (Which will in turn scratch
    other surfaces when you use the saw for cutting wood.)
    
    Colin