putting piers through existing patio slab

[JackOfDiamonds]

It looks like I'm making a 2nd story deck. I need to bring down the 6x6 posts and rest them on concrete piers. The ground already has an existing patio slab though. So I'm trying to figure out options.

Get a concrete saw, cut squares, and jackhammer out square holes. It will look terrible and sounds like a lot of work

Just wreck out the whole slab and have to re-pour the whole thing

Is there any other method I don't know about, like concrete saws that make nice circular cuts?

 

[JWILLIE1977]

Concrete core drill??

 

[JackOfDiamonds]

I need like an 18-inch, probably more like 24-inch diameter circle to put the piers in.

 

[firebirdparts]

Build a bigger deck.

 

[mike93lx]

Pictures could help.

 

[Youngandfree]

How ocd are you about how the finish looks? Cutting out squares for piers won't be any more work than wrecking the entire slab out. Will be much cheaper doing the piers also

 

[LXCam]

Depending on how large that slab is and what it would cost to replace it, I’d bring in a coring rig. 24” dia isn’t a big deal but you’ll have to live with patching the anchor points.

 

[Skiff Builder]

I'd rent the saw, make nice square cuts. When you drop in the tube, keep it at the elevation near the bottom of the slab- let the cut part of the slab be your form at the surface level. Finish the conc as best you can and place your post base brackets. Where I'm at, four holes would be a half day rental.

I never finish the top of a pier with a round tube-don't like the looks of it. Usually form a square about twice the size of the post if able.
Not sure of your soil type and whether or not you need to use a tube. We can dig a 18-24" base, conical hole through a 12"square opening.

Also could trim out the bottom of the posts to cover the slab cut/patch-ie brick or stone veneer if looks are paramount.

Enjoy your new build!

 

[JackOfDiamonds]

I think the base/footer of my piers needs to be either 18 or 24 inches diameter depending on what the permit office tells me, but the column can be smaller. I was going to dig the holes by hand, and bell out the bottom of the hole to size the pier footer, then use a 12-inch sonotube on top of that. It needs to be at least 24 inches below grade, but I was going to shoot for 30.

That means I probably need to cut a 16 inch or 18 square in the slab, to be big enough to dig through, which I think is possible with a concrete saw rental. Also, it looks like the piers will be close enough to the edge of the slab I can cut a notch out of the edge, rather than have to cut a square out. Good tips on forming a square for the post to sit on; I can see how that would look nicer.

 

[NUTTSGT]

I'd cut a square out of the concrete and if it looks like **** after it's done, cover the patchwork with something like this.

 

[lolaetype]

Is there any other method I don't know about, like concrete saws that make nice circular cuts?

Some places rent these things:

Core Drill with Stand 18 Rental | EquipmentShare

Rent Core Drill with Stand 18 at EquipmentShare. Book online today for state-of-the-art equipment with unparalleled customer support and safety features

www.equipmentshare.com

Maybe check to see if a rental store near you has them.

 

[wssix99]

Get a concrete saw, cut squares, and jackhammer out square holes. It will look terrible and sounds like a lot of work

Depending on the nature and size of the slab, cutting out sections could induce cracking across the larger remaining slab. Posting pictures and diagrams would help. It would also help to know how close you would be to any saw cut joints in the slab.

 

[JWILLIE1977]

My opinion still sides with core drilling. For several reasons, all mentioned above.

Cleaner look when finished.
Saw cutting won't get you all the way through the slab at the corners unless you cut past the corner.
No 90° corners for potential future cracks to begin from. Etc.

A 24" diameter core might be reason to call in a concrete coring service. I don't know of any rental houses in my area that rent a core drill outfitted with 24" diameter bit. Maybe rental houses are different in Utah.

At 24" dia. You are pushing the limits of all the readily available electric motors out there. A 24" bit won't be light, and needs to spin between 100 and 165 rpms for most effective cutting. Also need the right drill stand to accommodate a 24".
I am set up for 20" max coring with my Diamond Products CoreBore rigs. Things can get real serious real quick when you are spinning a 110 lb bit with a 6 HP motor at 250 rpms.

Anyway.

What are your soil conditions out there. . Rather than using concrete footings, can you use helical piles?
Might get you similar capacity with a smaller hole in the concrete.

 

[Milton Shaw]

Every time I read that title, I read putting "pliers through concrete". Anybody else have that problem with misreading sometimes.

 

[jetmechabq]

cut and resurface with this

Create A Safer Space With Rubber Stone Overlay | Rubber Stone

Softer to the touch and more flexible than concrete, asphalt, and wood, Rubber Stone adds an element of safety to spaces without compromising beauty. It is the perfect choice for residential and commercial areas prone to impact, like driveways, pool decks, and playgrounds. Find out how it can...

coveryourugly.com

 

[BombShelter]

Nobody uses 24" piers up here anymore, it's either Diamond or Handi Pier. I like Diamond at Home Depot cuz they also rent the bit and hammer drill to pound in the pipes, it takes about 5-10 minutes a pier. Of course you'd have to take a concrete saw and make something like 12" x 12" holes with around 8' of spacing to meet code.

Handi Foundation Systems | NCP Industries: Innovative, Sustainable Building Solutions

Are you tired of the laborious and time-consuming process of installing decking foundation systems? Look no further than our Handi Foundation Systems! HANDI

ncpindustries.com

Diamond Pier

Diamond Pier Foundations - Structurally rated no dig footings for decks, porches, pergolas, posts, and more. Code compliant, and install in minutes. Also available for larger commercial projects.

www.diamondpiers.com

 

[Uncle murph]

I think the base/footer of my piers needs to be either 18 or 24 inches diameter depending on what the permit office tells me, but the column can be smaller. I was going to dig the holes by hand, and bell out the bottom of the hole to size the pier footer, then use a 12-inch sonotube on top of that. It needs to be at least 24 inches below grade, but I was going to shoot for 30.

That means I probably need to cut a 16 inch or 18 square in the slab, to be big enough to dig through, which I think is possible with a concrete saw rental. Also, it looks like the piers will be close enough to the edge of the slab I can cut a notch out of the edge, rather than have to cut a square out. Good tips on forming a square for the post to sit on; I can see how that would look nicer.

Draw your square and drill the corners with a hammer drill and cut just to the holes,break out the center and you’ll have a nice neat edge to pour to after you install the column. I wouldn’t make it any bigger than you need to work through,you can angle the sides out to whatever size you need.I’ve done it many times.

 

[signcrafter]

I think the base/footer of my piers needs to be either 18 or 24 inches diameter depending on what the permit office tells me, but the column can be smaller. I was going to dig the holes by hand, and bell out the bottom of the hole to size the pier footer, then use a 12-inch sonotube on top of that. It needs to be at least 24 inches below grade, but I was going to shoot for 30.

That means I probably need to cut a 16 inch or 18 square in the slab, to be big enough to dig through, which I think is possible with a concrete saw rental. Also, it looks like the piers will be close enough to the edge of the slab I can cut a notch out of the edge, rather than have to cut a square out. Good tips on forming a square for the post to sit on; I can see how that would look nicer.

If the posts are by the edge of the slab dig next to the slab and pour your footings.

 

[billconner]

My buildings departement said just anchor posts to concrete slab. It's only 5" but has a 12" gravel base. I'm not worried in the least bit and glad I don't have to cut it.

 

[andyvh1959]

How about cutting the square hole as needed. Dig the holes and set the posts. Then fill in the square hole with concrete flush to the current slab. Then have the current slab coated with one of those garage floor epoxy finishes. I've seen porches and patios done this way even up here in Wisconsin, looks good, durable.

But the idea of building around the posts with brick or stone to the size of the square holes to me is the option. Looks good, gives the post some heft to make it look less spindly, adds some more style.