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Leveling Pavers over Concrete

Hi! We're going to be redoing our front patio by placing stone pavers over the existing concrete, placing a layer of sand between them and using mortor for under the border stones. I know that having somewhat of a slope is good to help the water drain away from the house, but our existing concrete patio is really sloped - much more than is needed. Several questions about this:

 

1. How much of a slope do we need to leave to allow for proper drainage?

 

2. Our current concrete is in pretty good condition, but has a few cracks along the house from settling decades ago. We're pretty positive it's not going to shift anymore. Do we need to worry about and/or fix those cracks before we start? 

 

3. Can we use the sand/mortor to level the areas we need to, just putting more in the areas where is needed? Or should we put down thin layer(s) of concrete to level first? I've seen conflicting opinions of this online. 

 

Thanks so much!

Lauren

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Posted 2013-05-30T14:18:41+0000  by 40Crook 40Crook
 

Hi Lauren,

 

Great question, and welcome to The Community!

 

The feasibility of this project depends on the severity of the slope. Adding sand to the solid patio surface will present a challenge to keeping the sand in place under the pavers. Water will only facilitate the sand to wash out from under the pavers.

 

Locking the outer edge stones with adhesive will likely cause a damming effect that will lead to additional issues in the near future. Water will penetrate into the sand layer and cause problems, particularly in the winter.

 

The normal slope should be at least 1 inch of drop for every 8 feet of length. Slope that is greater than 3 inches in 8 feet is beginning to become severe.

 

Cracks (particularly along the foundation) should be sealed before adding anything to the patio. Shop here for products to accomplish this. 

 

 1 qt. Concrete Crack Filler

 

Adding concrete over old concrete usually doesn't work, especially when feathering the transition to level. There is not enough adhesion when the layers are thin.

 

Personally, I feel that a better choice for your patio would be EnviroTile. EviroTile is rubber and can conform to the slope more easily than concrete pavers. They are molded for drainage on the bottom and can be glued into place with construction adhesive. There's no need for any underlayment on your patio.

 

9c4adffe-45c2-46bb-be35-730589945080_300.jpg

 

Read through this extensive thread on our community for all the details:

 

 A New Designer Life for an Old Rubber Tire: Multy Home EnviroTiles™

 

On a severe slope, add extra EnviroTile Clips to provide additional support for the tiles and to allow for better drainage.

 

Good luck with your patio makeover.  Post back with pictures.

 

 

Travis

 

 

Posted 2013-05-31T15:05:57+0000  by Travis_HD_ATL

Hi, Travis! Thanks for your detailed response! The Envirotiles do look like a good option. I'm afraid even using those, the patio will still be visibly unleveled however. Is there a way to level underneath them?

 

If we do still want to use stone pavers, would a self-leveling underlayment work to level the existing concrete? I guess I'm a little confused because in HD's DIY Project Section (http://ext.homedepot.com/community/blog/how-to-lay-pavers-over-existing-concrete/), it says we can level with the gravel/bedding sand mixture we lay below the pavers, and that this will actually assist with drainage. I saw that some other people just used a medium bed mortar (with and/or without a membrane), to level out the concrete, and then applying the pavers directly. Would this work in my situation?

Posted 2013-05-31T18:49:20+0000  by 40Crook

Hello again Lauren,

 

I may be assuming (and you and I know what THAT means) that your slope is greater than it really is. 

 

Self-Leveling underlayment generally applies to surfaces that are uneven by fractions of an inch that need to be perfectly level. These products will not  help to correct a slope. In fact the patio requires some slope to drain the water away from the house.

 

Leveling sand can be used as an underlayment to correct a slight slope and the worst that can happen is that the sand will wash out and need to be re-established. If the stones are not permanently fastened down, it is a relatively easy fix.

 

Here's a post from the community that should encourage you: 

 

http://community.homedepot.com/t5/Build-Remodel/laying-pavers-over-concrete/td-p/10967

 

It looks like they used Collier Metal Edging to hold things together.

 

COL-MET 8 ft. Brown Steel Landscape Edging

 

This edging is 4" tall, so it can support a 4" correction in slope.

 

 

Travis

Posted 2013-05-31T19:31:11+0000  by Travis_HD_ATL
 
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