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Ok, but won't it be danger of sand washed away with the time since concrete does not absorb water? should i drill some holes in the concrete to provide drainage? or its bad idea cuz it will weaker conctere base? another thing i was not correct by saying concrete all over the place. there wil be 70% paver over concrete and 30% over gravel sand base. since i wil be laying paver over 2 different bases - would it sink differently with time?
i can send some pictures if it helps
If you embed 12" of the edge all around the complete area of pavers in thinset mortar, you will in essence have created a dam for your sand and it will not wash away. You only need 1" of sand unless you intend to regrade the patio. If it does not currently slightly slope to allow runoff, you may wish to consider this. If you are going to have 30% over gravel and base make sure you use a landscape fabric under your gravel. Rent a power tamper / compactor and compact your gravel well one layer at a time. You only need 1/2" of sand. Some say only 1/4" but you may compact your gravel to the top of the slab and then use 1" of sand over the gravel. After setting your pavers sweep DRY mason sand into the joints. This will provide for the majority of water to actually run off if you have any slope at all. No holes in the concrete. If your soil in the 30% area is not stable and hard, or if the drainage is poor, consider up to 8" of compacted gravel under 1" sand. Properly compact the gravel in 2" to 3" layers and your 30% area should not sink.
We have done a significant amount of brick and paver work over 27 years and have never received a call back. We did our own driveway 15 Years ago and it is the only one I see regularly to watch what it's doing. We took a single car driveway and installed Old Chicago Brick on it but when we installed the brick we made it a double drive. Thus, 50% is on a slab and the other 50% is over dirt. Besides a few roots occasionally giving me a headache, both halves of the brick remain at the same level and we drive on it.
We are about to install 2700 Sq feet of Old Chicago on our (NASTY) Chattahoochee pool deck. I have the pallets of brick sitting in the yard just waiting to find time to do it. Im goinng to do it just like I told you to do yours
thank you for details explanation. to recap - i will leave concrete and put gravel over it and then sand. sand should be 1 inch but what about gravel over concrete? how thick it should be? 1-2 inches just to level out concrete? or more?
regarding the sand - what is better? sand or so called "screen" ? if sand can i use same sand as underbase and them to fil the joints? i think its called torpedo sand
No gravel on the concrete slab just 1" of coarse concrete sand and then the pavers on top of that. Do not use stone dust or screenings.
In the joints, use mason's sand.
Sorry, but these two are different sands.