I did most of the work on my slab myself. It was a lot of work, and I had no experience with concrete beforehand.
I rented a concrete saw and purchased a diamond blade for the saw. My friend towed it to my place. He ran the saw while I did my best to control the water flow to prevent/mitigate damage to objects in the garage. The rental was around $70 I think and the blade might have been around $85. I still have the blade -- there's about 50% of its life left on it.
I rented an electric impact hammer and broke the floor up into manageable pieces over two partial days. That cost around $60 I think...?
I removed the chunks of concrete and carried them to a dumpster that I had delivered to my house. I recall the dumpster and the haul-off cost me about $250.
I spent weeks removing the crushed granite base (saved for later use) and excavating thick, sticky clay soil from the area with a shovel. I still have a big pile of dirt in the back yard from that experience, and it's even visible on the "bird's eye view" photos on
Zillow.com!
I then had to use an electric demolition hammer to chip off messy chunks of concrete off the
foundation that had spilled out under the forms when the foundation was originally poured.
What had been inconsequential under the original slab was (I believed) relevant, if not critical, in my effort to build an
isolated slab. The demo hammer rentals cost around $100 for the all the days that I used them. I spent much of Thanksgiving Day chipping away at the foundation.
I bought 12" tall concrete forms and stakes ($100?), cut them to correct length, and then installed them (level).
I had to add more stakes later to make them more stable, this time using steel stakes (more expensive, around $35-40?).
I had a yard or so of crused granite delivered to my house, which I then moved one shovel at a time into the "pit." The crused granite delivery cost around $200 I think. (I kept no records. I suck!
) I also used the crushed granite that I salvaged from beneath the original slab.
I tamped all the crushed granite with a hand tamper.
I hired a professional concrete contractor to lay down plastic, insert all the rebar ($250), and position the J-bolts that I bought previously ($40?) in final preparation for the pour.
I had our pest control company treat the soil with Termidor termiticide ($550). I also plumbed a "termiticide injection system" that will allow for the area to be retreated in later years (every 5?) without having to drill into the slab. With a gap around the slab, I was quite concerned about termites forming mud tunnels and destroying the walls over time, unbeknownst to me or anyone because of
inaccessibility and inability to see the damage until it was much too late.
Perhaps this was overkill/paranoia, but I learned a lot about termites at that time, and it's scary!
I passed my concrete forms inspection (the building permit requires this).
I hired the same professional concrete contractor to handle the pour and finishing. The concrete delivery (5 yards, 3,000 psi, plus fiber mesh) was $770 and the bill for his time was around $300 I think.
There was an additional one yard "mini pour" that I had to do in an L-shaped area where the old slab met the new. I did all that work myself, with the exception of renting the mixer filled with concerete... That was a couple hundred bucks, and I was able to use my concerete contractor's rebar bender free of charge.
Overall, I'm very pleased with the outcome, but it took me a looooooooooooong time, as can be found in my project thread. I too had considered hiring a pro to do everything at first, but I had trouble finding a
licensed professional contractor to do the work amidst the peak of the building boom out here.
I wasn't getting calls returned -- I guess the job was too small to care about from their perspective.
I should also point out that at the time I did this, we did
not yet have the benefit of Rod's book. I probably would have done things differently, such as
not set forms at all for the new slab, instead using a foam board/roll around the perimiter, figuring that would provide sufficient isolation from the rest of the structure. I also think I worried too much about flanking across the slab at the time, because that was an era on the forum when floating floors were seen as typically necessary, whereas the tides have shifted considerably since then.
Sorry for the ramble... Hopefully there's some useful information in there somewhere...
--Keith
