Laying flagstone over existing concrete patio-need to expand patio?

by Nicole
(Dallas ,Texas, usa)

I have 2 contractors telling me different things. I have an exsisting 9 x 22 concrete patio in good shape. We want to overlay it w/ flagstone and expand it to about 12 X 25.


Contractor 1: says he needs to tear out existing patio and pour a whole new patio or else the flagstone will not lay right and I will end up w/ cracks in few years. (very expensive) He is actually pushing Belgard pavers if I am not interested in tearing out the exsisting patio.

Contractor 2: says he does not need to tear out the old patio. He recommends extending the patio by pouring additional concrete and than just lay the flagstone over the old and new area of the patio. (less expensive)


We are on a budget. We could afford to expand but not a tear out. However, I do not want to be pennywise and dollar foolish. I am considering the pavers but I really prefer the look of flagstone.

Other info.: I am in North Texas and we would be using OK flagstone. Please advise

Comments for Laying flagstone over existing concrete patio-need to expand patio?

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flagstone overlay over exposed aggregate
by: T.K

We have a small existing patio(11x12) of exposed aggregate that has a few cracks in it. We want to expand it to12x14 and put a 1&1/2 inch bluegray flagstone overlay.
Option1: use existing base and pour additional concrete for expansion and overlay with flagstone using mortar for joints.
Option 2: Remove all old concrete use sand and crushed limestone base with flagstone and polymeric stone dust in between stones.
We have 2 contractors giving us 2 very different options.While we are on a budget we do not want to have problems down the road
We are in middle tennessee where we do get a hard freeze .
What do you think is the best and cost effective option.?Or can you recommend something else?

flagstone overlay over exposed aggregate
by: T.K

We have a small existing patio(11x12) of exposed aggregate that has a few cracks in it. We want to expand it to12x14 and put a 1&1/2 inch bluegray flagstone overlay.
Option1: use existing base and pour additional concrete for expansion and overlay with flagstone using mortar for joints.
Option 2: Remove all old concrete use sand and crushed limestone base with flagstone and polymeric stone dust in between stones.
We have 2 contractors giving us 2 very different options.While we are on a budget we do not want to have problems down the road
We are in middle tennessee where we do get a hard freeze .
What do you think is the best and cost effective option.?Or can you recommend something else?

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Flagstone over existing concrete underway
by: Same Boat

I have a 15x15 concrete patio that has been expanded to about 17x20 with additional concrete. The entire surface is now being covered with Oklahoma flagstone. It's going to look great!

how do you drill flagstone/ashlar
by: Anonymous

have an fireplace cover need to drill 1/4holes into stone to hang mantel over the stonesurface what type of drill bit need to be used tryed hammerdrill bit blue granite(made by bosch)

how do you drill flagstone/ashlar
by: Anonymous

have an fireplace cover need to drill 1/4holes into stone to hang mantel over the stonesurface what type of drill bit need to be used tryed hammerdrill bit blue granite(made by bosch)

stonemason
by: chadpasley

Hi, I am writing in regards to the laying of flagstone over new concrete, and over the existing concrete as well. I am a stonemason/concrete professional, and have almost 15 years experience in this type of work--and have built hundreds of these types of patios. Here is something to remeber--you can lay the flagstone over the new concrete and existing concrete, but I want to stress this point--you have to tie the new concrete in with the existing, if not, it will most likely move and send cracks up the edges where both met. Make sure that you tie them in correctly and make sure the new concrete is steel re-enforced with rebar--you have to make sure that the existing concrete is in good shape as well. I, too, live in North Texas--so I know what our soils are capable of.

flagstone
by: Sam

Expand concrete then cover with flagstone

Flagstone over 2 surfaces
by: Anonymous

I have a concrete slab patio that I am expanding using compacted sand over 3/4in granite with flagstone over the whole thing. My problem is i have tried polymeric sand and crushed granite as my grout so far and they both have failed miserably. I want to know what is the best product to make a firm grout joint over 2 different surfaces that will resist chair legs and prevent the stones from moving. I know starting over and pouring a concrete base around the existing would be the best bet, but Im out of money and time and patience. Is there any solutions with out tearing up my flagstone and starting over?

not sure if its to late
by: Anonymous

hey nicole, so you can definately go with contractor number 2, if he is experienced. The thing about adding a few extra feet to your existing patio is that first you have to make sure that your patio doesnt show any signs of cracks or holes, if there are any cracks you would have to repair them asap. then you can drill your existing patio on the sides to allow the new patio to bond well with the old one. and drilling holes lets any extra air pockets escape so it will keep your foundation from cracking. even though its just a patio i strongly suggest adding wires or at least a wire mesh before pouring the new patio. make sure all your measurements and cuts are accurate, because the only difficult part about laying flagstone is if you do it wrong, its a headache to do it over again. If you really wanna save money you could definately do it yourself, just let me know if you need any suggestions or help, and if this reply is to late, im sorry. but just keep it in mind for future references. peace

Laying flagstone
by: Jill & Kevin

Hey Nicole,

We too were in the same perdicament. We had gotten some estimates to expand our existing concrete pad because we were thinking of doing the same exact thing. after the addition we wanted to do the flagstone overlay. Well we said the heck with all the pricey estimates & decided to di it ourselves. We had some help of course with my father who has done it before, but we saved ourself a lot of $$ & headache. We went out & purchased our own mixer & decided to go for it. We made sure we added some rebar to the existing concrete on all sides of where we were going to add new & then we just set our forms & poured the concrete. It looks great now & we are going to wait a little time for the new concrete to settle a bit & then we will eventually lay the flagstone on top. Moral of the story, yes you can lay new concrete down with flagstone overlay. But like David said just make sure you include the rebar to prevent cracking. & no you most certainly do not need to demolish the existing. They are just trying to dwindle more $$ out of ya. Good luck.

Laying over an old patio.
by: Anonymous

If your current patio was not done with rebar and you are showing vertical movement (variation in height) along a crack or expansion joint, then you may want to consider what the first contractor is saying. I replaced my cement before laying the flagstone to insure that I don't get cracking in my flagstone.

contractor 2 is right
by: David

Dear Nicole,

You can go with contractor 2. My dad has done that many times. You just need to make sure that the concrete guys tie the new concrete pad to the old concrete pad. That's usually down with dowels.

Great luck!

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