Some background: We just built a new house and had concrete porches poured along the front and back of the house. The builder used sand/clay fill from on site under each porch and poured footers under the corners and edges. Over the winter the slabs settled poorly/heaved and the entire slab on both porches cracked bad. My builder admits it’s bad and has suggested cutting 2’ from the house and around each of the posts and tearing out and repouring the entire thing. He’s hesitant it would look good but can’t think of another option.
My proposed solution: I suggested we install flagstone over the concrete but I have some questions/concerns:
-Can flagstone be installed over concrete even if it’s cracked?
-What do you do on the edges to keep water from getting up underneath the flagstone?
-I THINK the slab is done setting/cracking, but if not there’s obviously risk of the mortar joints between the flagstone cracking.
What’s everyone’s thoughts on this approach? Any other ideas besides ripping out the entire porch slabs?
by Intelligent_Draft320
19 Comments
You should post this for the people in r/concrete.
That’s a really bad crack. Looks like it shifted. I’d be worried about the rest of the slab.
It’s not done settling or heaving and those cracks will go right though to the Flagstone.
Only way to fix it is tear out and replace. Needed a saw cut down the middle of it and I doubt it has rebar with how big that crack is (needed also). We generally pour sono tubes to top of slab for posts like that, too. But if it had a cut down the center and proper rebar, this shouldn’t have happened. Our warranty is for cracks over 1/8” in the first year, so this would 100% fall under warranty work. What he wants to warranty exactly is another thing.
This is a situation where waiting for it to settle completely is best. How long did it take to crack on both sides?
tear that shit out that slab is fucked. Water has washed away the subgrade if they even did that. there’s voids underneath that slab clearly.
IF you were to try and cover that with flagstone, you would still need a bedding base of a few inches. A decent flagstone will be 1 1/2″ thick. So you propose raising the level of the patio by 4″…..
So you would be stepping up (tripping) every time you came out of that doorway.
Bad idea for that reason alone.
I’m just a homeowner here… but we covered a small porch with flagstone to cover some concrete imperfections and it looked nice for a while. After a few years, it became apparent the top layer of mortar and the stones were not really adhered any longer, despite all the etching of the original concrete and special solvents to prepare for the new top coating of flagstone and mortar. The stones began to break away and had a hollow sound when you tapped on them. It was only about a 10-year fix when we ultimately had it all demoed and poured a new porch. So it was just a waste of money and effort.
That’s not from a bad winter. I guarantee you they didn’t pour a proper footer for the posts and just put them on the 4” thick concrete pad. Code where I’m from (South eastern PA) calls for a 36” deep footer for any kind of weight bearing post.
That may not be done moving. Pump level it or replace
The correct base was not laid before concrete was poured!!! Putting a layer of ANYTHING over this porch will also crack and fail. You’re in a horrible situation and anything other than demo of porch, correct base laid and repour of concrete will be a complete waste of money & time.
Seems like you need to see how big your footers are. They don’t sound big enough or done with proper sono tubes. Once you know those footers are secure which hopefully doesn’t involve having them redone then I would remove the concrete install flagstone or pavers properly. Imo
Maybe use Golden Select patio tile on top. Just need to edge well so no movement and you can always reuse down the road. Google that brand.
That is not a crack. Thats complete separation. Anything you pervorm on this surface will mean more heartbreak
Sorry to see this bud but I wouldn’t spend anything covering this up until it’s repaired properly.
You can have a flagstone porch but you’re going to want to demo out most of that concrete and set them on a fresh bed fresh bed of mortar so the levels are right with your doors and such.
Build a dry stack wall around the edge of concrete, high enough to allow for 3-6 inches of crushed run and about 2 inches of crushed gravel (powder) which you will dry set the flagstone in. Do a thin layer coming out of the house with a step up to the new level of the patio. The dry stack border and permeability of the crushed granite and crushed run should keep water draining, prevent frost heaving to a degree. The cracked concrete may shift up and down a bit still but it won’t move side to side as well.
I have no idea if this will work but i suspect it would.
Not sure how this might effect the posts long term.
My worry would be the posts. You say the have their own footer. You could cut around the posts so the concrete can move independently from the posts. Lay some pavers on 5cm crushed stone on the porch area. This way the concrete can move and it wont look too bad on top. Be sure to leave a gap between the pavers and the wall of the house so the wall can breath and fill with some nice looking gravel. After a few years when the concrete has settled into place, if its noticeable on the pavers, you can easily pull up them up and put more crushed stone to bring it up to level again. I wouldn’t try and stick anything to this concrete as it is.
This needs replaced. It’s brand new with serious issues. Do not cover it up.