[Mouse51180]

I currently have a 14x16 concrete patio I am about to build a pergola over and have also decided to lay stone tiles over the concrete instead of staining it to give it a new look.

I was looking at my plans and realized this would be a perfect opportunity to extend my patio out another 5ft so it would be a 14x21 patio with some more seating room.

After going to Home Depot and shopping for supply and trying to read up on laying concrete I saw that the store has a 4in solid concrete block.

My question is this. Instead of trying to lay a whole new slap of concrete to and trying to join it to the current slab just to go over it all with stone tiles... could I just save some money by digging out the new patio extension... lay some base gravel down and level these blocks to the same height that the current patio is at or am I looking at issues later down the line since it would be technically two patios bumped up against each other?

Hope I explained this well enough. Thanks for any help.

[ballengerb1]

Yep, pretty much 2 patios bumped againist each other floating at different rates. Lets hear how you were going to attach or lay the stone to the old patio first>

[Mouse51180]

Pretty much just grout the tiles on both patios in one pass and then use a sealant over the top.

[ballengerb1]

The new section not on the concret pad will have cracked grout lines in less than one year.

[Mouse51180]

If I did a 1 inch concrete top over the cinder blocks would this resolve that issue or should I just extend the patio with 4 inches of new concrete?

[ballengerb1]

1 inch of concrete will crack fairly easily so don't wast the time/money. If you want a pation to last do one of two things. Pour a new slab or tear out everything and lay your stone in limestone screening or sand.

[Mouse51180]

Thank you for the advice.

[21boat]

If you want a pation to last / Pour a new slab

I disagree here.

Mouse what is you Geo in temp changes?

Didn't quite understand the 4" solid block application here??

How is the patio now?

If it were poured as a new slab you would need grooved crack controlled joints at that size patio. ( didn't gain anything here ) The reason its not a everyday practice is because the new pour would look to different then the old in color.

Therefore a 5' addition on the long side in essence is a grooved crack control joint line already. If that was tied in with rebar at an angle the slabs would have a mating at that point structurally for shear and heave. If you put in a below grade footer even better.

The bottom line here is any of it can crack period extension or not. The deal is to control the crack where you want it to crack. Any tile etc on a floating slab takes a great risk of cracking in temp differences. If the slab was looked at in poured sections then a 5' is a non issue period. We lay walks on Crete with a brick band where the groves are and also where the expansion joints are. This is a doable thing as long as you are satisfied in the lining up the grout lines for a future crack. Pouring a whole new slab and you would essentially be back to where you are now. That's the basic mechanics of Crete and science here.

I would score cut into old Crete to create that control joint. Done on the Job site all the time... Commercially also. Res or commercial its still Crete.

Most of this depends on how the original patio is now in cracks... If that's in good shape see no problem here at all in Crete science

It's a large side walk and deal with it as such

[Mouse51180]

I live in Charlotte NC. Average high go from 50s-90s throughout the year.

Average lows go from 30s-70s throughout the year.

This is a new construction house. Only about a year old and my wife thought the patio was poured 4in thick. I am hoping to get around to digging a small chunck of grass away from the patio this weekend and see exactly how deep it really is.

[ballengerb1]

21boat, the way I read this he has a 14x21 concrete patio and want to extend it 5 more feet using gravel and 4" block rather than pouring a new section of slab. Then he is going to cover the old concrete patio and the block with grouted stones. I can't see how this is not going to move as two totally different patio units. His grout would be popping after the first frost.

[21boat]

I assumed he was pouring a new 5' section of slab.. That's why I mentioned didn't understand the 4" block part.

Didn't quite understand the 4" solid block application here??

This threw me in that direction also.

Yep, pretty much 2 patios bumped against each

4" block dry laid block to me wouldn't constitute a "patio" on the get go..
Sorry for my confusion here.

I guess it was because, I would never dream a person would think of laying 4"x8"x16" solid block sideways and would consider it to be anything but block in stone and not a surface to lay anything on except to park a lawn mower on.

I guess the real thought is how is the top going to end up.

[Sarahfil]

What about the use of a polymeric sand in the joints instead of grout? Would that make a difference to allow for a little more give, less cracking?