My home builder poured me a nice thick (16") concrete patio (8'x10')
which we didn't ask for or pay for. Unfortunately it's squarely in the
way of where we want to build a deck and there isn't really clearance
above it to get the deck joists in.
I'm still fighting them on trying to get it removed, but they must have
the worst customer service department imaginable. The fact that it
cracked in half while still under warranty wasn't enough to get them to
I've called a few concrete contractors and can't even get one to give
me a quote.
It's in the back yard and I dont have the gate clearance to get a
bobcat or similar through.
As a result it's starting to look like i'll be doing this myself :( .
I've never done any concrete work on this kind of scale, although i've
got friends who've got some experience with jackhammers and excavation
and will work for beer. One suggested that i rent a big hammer drill
and drive a grid of holes into the slab which I could then drive a
jackhammer into and break apart... is that plausible?
How likely is it that a builder would put rebar into a non-structural
Any other advice?
Rent a air powered 75 or 90 pound jackhammer. Make damn sure your neighbors
are up before you start. You will be done in a couple of days, based on
16" thick. Then comes the fun of removing the chunks. Using your
measurements you have about 4 yards of concrete, weighs about 8000 pounds,
give or take. I would have a roll off delivered and put the concrete in
that. Last one I got was $200 bucks. Beat the hell out of driving to the
dump with my pickup. Better ask before you rent, they may have weight
As for reinforcement? I do not know where you live. Where I live footings
for the posts are 16' deep and yes they have rebar in them. We do not pour
slabs that thick.
Personally I would be considering flagstone or tile instead.
Please do not call me the weekend your planning on making a LOT of
Thanks for the advice.
I've been quoted $325 for a roll-off if i'm filling it with concrete -
i might be able to find cheaper since i'm only about a mile from a
It appears to be an on grade slab. I dont think it has any footings,
i'll do some digging this weekend and confirm that.
I'm just glad it's not my front porch, that thing is about 12'x6' and
about 5' thick, it is structural and has footings below that!
I suspect the grade around the house has a lot to do with how thick
these things are.
I will need to backfill around the house to meet the engineered
drainage requirements. Is there anything stopping me using concrete
rubble as part of the fill? It seems very excessive to have to
wheelbarrow the concrete out and then move fill dirt in to replace it.
SQLit's advice is sound but his weight calc is off.
You've got 8 tons (16,000lbs) of concrete, in SoCal that's nearly a
full lowboy rolloff (17,000)
"One suggested that i rent a big hammer drill and drive a grid of holes
into the slab which I could then drive a jackhammer into and break
apart... is that plausible?"
In my concrete demo experience, no this will not work. It's a very
good way to get the jack hammer tool stuck. You've got the attack
this things from the outer edge (about ~8 to 10 inches in)
Unreinforced concrete fails when subjected to tensile stress. I would
suggest digging the slab free along one edge so that the slab can
"break to a free edge".
This beast is so thick it will be a lot of effort.
You might consider a BobCat with breaking hammer on it, it will make
short work of this.
Thanks for the advice.
I'd though it'd be about 8 tons also. The hauler i spoke to required
that we rent a full size rolloff if we are doing anything concrete so
that's probably ok.
The slab is free on two sides and buts against the foundation on two -
it shouldn't be hard to figure out where to start.
How wide are bobcats... i think we only have 32" clearance on our gate
and i could perhaps get 40 if i tore out a couple of fence posts.
Well we'd like to put in a 350 sq ft deck and since the slab is within
an inch or two of the interior floor it doesn't allow us to put joists
over the top of it.
I'm pretty sure that code prevents us from actually fastening the deck
support to the slab (as it's not structural).
The only other option (that I can see) would be to nail 2x4's flat onto
the slab and lay the decking boards on the 2x4's. The rest of the deck
support would end up being freestanding on concrete piers and perhaps
attached to the house in a few places. Unfortunately since the slab is
split clean in two, i'm worried that it could move apart and warp the
here are some points to ponder: what is the frost line in your city. if
any? what is the depth for foundations and footers required for your
town? you need this info for your deck footers. the builder may have
put in a 16" foundation with only a 4" slab, or whatever is locally
required. ask your permit office what was required and what do the
building plans or blueprints show may be similar to what you have. what
does your survey show?
Thanks for the advice!
The slab is about 12-14 inches above grade and feels like it averages
only 4 inches below it. I'm shooting at 16 as a typical depth, although
i really haven't done enough excavation to know that for sure.
I didn't think it was structural and doesn't appear to have piers under
it (like my front porch does) although, again, i've only done a cursory
check for such things.
We're just outside of boulder colorado and for foundations i'm pretty
sure that the frost line requires that foundations be 32" below grade.
Could it really be 16 inches thick? That seems awfully thick for just a
patio. Anyone know what that would support, weight wise?
I have looked at putting in a garage slab, an 4, 5, or 6 inches is
normal around here. 16 would be rediculous.
I don't know what this thing looks like, but might it just be a
floating edge-thinkened slab? They would have mounded up dirt and fill
in a rough shape of the patio, then poured concrete on it to make a 4
inch layer on top, and about 8 inches or so on the sides.
But it seems like the buildter really needs to take care of this. Small
claims court might help, perhaps? And lifting 8tons of anything by hand
is no fun. I did a few tons of dirt by hand last summer, over the
course of several weeks. The payoff was a nice garden for my wife. Your
payoff will be a nice hole where once there was brand new patio. If you
really have to do this yourself, wouldn't it be worth it to take down
the fence and get a bobcat in there? (At least, I've been looking for
an excuse to rent one, and your situation seems like a great excuse).
The height is pretty much forced by the grade, but it's entirely
possible that there's a mound of dirt under it.
I'm not so phased by the 8 tons. I moved about 3 tons of topsoil last
week in an evening and have moved 5 tons of stone over the course of a
few weeks before. With a few helpers it could be over pretty quick.
DR Horton just agreed to come out and "take more photos" of the crack.
I'm not sure what that'll prove but hopefully they'll fix their
concrete costs money wonder why the builder put it there? I guess you
consider small claims court against the builder.
if you had room a backhoe would do that job a lot easier.
to find the thickness drill with a masonary bit or preferably rotary
hammer drill in a few places
The builder probably has about 50 truckloads of concrete coming into
the subdivision each day, i wouldn't be too surprised if that's a
fairly constant number and if they have excess the pretty much just
need to dump it.
My front porch is 5 foot deep in places and it's definitely not got
dirt piled up in there, though it may have some voiding material.
Good point on drilling holes though - i'll need to buy a longer
masonary bit first though.
I may need to go to the small claims court.
The builder (DR Horton Melody) is doing everything in their power to
avoid spending money. I've spent hours arguing with them and had to get
my towns planning department involved just to get them to meet building
codes. And they are still holding out on putting a railling all the way
around my 5ft high porch.
Getting them to honor their warranty document seems like a pipe dream
Well, the crack, that's a problem, but I would never remove a patio to
install a deck. Still...
I find it amazingly unlikely that it's 16" all the way through: it's would
almost certainly be only that thick on the edges and substantially thinner
at the center.
Still breaking this thing up would be an amazing PITA. Don't go the
jackhammer route that tpeople are suggesting: that should be your last
resort. Instead go with an expansive demolition agent.
It's a special sort of expanding concrete that you pour into hole
strategicaly drilled into what you want to break apart. As it sets, it
expands and the force quietly breaks whatever you've got.
But I'd keep the slab.
Either lay sleepers on the slab to support the deck, as you suggested
elsewhere, or build your deck around the slab, maybe 9" down so as make
the deck a step if the grade if the site warrants such a thing.
After drilling the holes, pour in the expansive mixture and then drink the
beer while waiting for the thing to break up.
Hard to say, but I rather doubt it.
Yeah. concrete is wonderfull stuff: don't get rid of it.
Good luck with whatever you decide to do.
Remove the dead poet to e-mail, tho CC\'d posts are unwelcome.
Mean People Suck - It takes two deviations to get cool.
I think this suggestion wins, anything that moves the beer drinking up
in the schedule.
The question remains where do I buy this stuff. I've never seen it on
sale and none of the websites seem to be selling it.
I also imagine i'd have to do this is pieces starting from the sides
that dont touch the foundation. I dont like the idea of those kind of
forces being misdirected.
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