I am planning on beginning a dry laid flagstone patio (live in Zone 8 in Texas Hill country) and plan on laying my flagstone on three inches of decomposed granite and two inches of sand base. This is my first time to lay a flagstone patio and I have a few questions on my proposed installation I thought I would ask the experts here. I am going to lay the patio at the bottom of my concrete stairs that come down from my covered elevated porch (part of foundation) that is 2 feet above ground level. Our lot slopes away from the house gradually and the highest point on our lot is against our foundation. I have a few questions on how to lay the patio that I am hoping someone may be able to answer for me. 1. I am planning to raise the patio slightly above ground level (3") to make it an easier transition from the stairs to the patio. Will raising this slightly against my slab cause me any problems? 2. Do I need some type of edging between my flagstone and the slab? 3. Since I am raising my patio slightly, do I need to use stone edging around my flagstone or build a retaining wall on the lower end or will steel edging suffice? 4. If I use stone edging will it be difficult to keep the flagstone level with the edging? thanks for your help and any suggestions!

I just bought a house with a pool and the surrounding pathway is all flagstone. The problem is that the stone seems to be flaking and seems to sound hollow and weak in some areas. What can i do to fix this and hopefully seal the flagstone from deteriorating so much or completely? do i need to chip away the loose/flaking top part of the the flagstone until it's solid? what is the best solution without having to replace them? i could send pictures but am not sure how to do that as i am new to this forum. Any help is much appreciated.

Let's start by talking about just what 'gravel' is. The term seems to find a variety of definitions around the country, so before we talk about your issue, it might be useful to let you know what 'gravel' is around here in New England, then you can decide is what you have is similar. 'Gravel' is a well graded, hard, durable, and natural sand and gravel, containing no organic (loamy) soils. It's free draining, which means water will readily pass through it. And it has a natural moisture content that lends to it's ability to be compacted to a very dense and hard consistency. Now, if that's what your dealing with, what does that mean to you? It means that if what you excavated from the hole is more organic, loamy, or silty in nature, and not completely mineral soils (like gravel), then you need something else to use as a base, and dispose of that which you 'dug out'. If what you've purchased is similar to the description above, having no stones larger than an a half inch or so, then it will make an acceptable base for your patio. The caveat here is that whatever you use, it needs to be both free-draining, and it needs to be very well compacted, preferably using a vibratory plate compactor, so that when you walk on it, pretty much nothing moves. Sand, by itself, as a base material, does not lend itself to deep compacted layers. Look at the stuff closely, and you will see that the particles are rather rounded in nature, and even thought the particles are small, they will react to compaction much like marbles, and ultimately they can move. In the construction industry, gravel, while capable of being readily compacted to an acceptable base, isn't what the pros will lean towards due to the inclusion of stones up to and including an inch and a half or so, and they don't want to spend the time picking them out. So, what does the industry use? More often than not, and depending on location, paver and bluestone bases are contructed of either crushed gravel, or crushed stone, or what is called crusher-run. Crushed gravel is natural gravel that has been 'processed' to eliminate stones that are too large by crushing them, and yet not requiring a sieve to pick them out of the material. Crushed stone is just that, a by-product of a quarrying operation that is crushed and then processed through a series of sieves to separate the particles by size, eliminating any and all fine particles, and creating uniformly graded products from 1/4" crushed stone up to 6" crushed stone. Crusher-run is another by-product of a quarrying operation, where stone is crushed and processed only to insure that no particle is larger than about one inch or so, with everything after the crushing operation left in the mix. When crushed stone is used, it is on the smaller end, 1/2" or so. Beyond that, compaction isn't an option. Crushed gravel and crusher-run can be more densely compacted as the particles within are all pretty much angular, and will fill just about all available space within the layer when compacted by machine. Sand and stone dust are used as a setting bed, no more than 1" to 2" thick, compacted, and then screeded to level. Bluestone, flagstone, or pavers are set on top of that. The dust and the sand can be worked by hand within the area of each stone in order to achieve a level final paver or stone surface. In your case, if you already have the gravel, it's free of large stones, you can likely use it, compact it, and place a layer of sand or dust on top as the setting bed. The keys really are....free-draining, free of large stones, and very well compacted. The material choice to fit that bill has a number of choices.

Hi everyone, We live in the dallas metroplex area, where we have clay soil, and are planning on getting a patio built. The question is how much should the thickness of the concrete base be? We've been told by friends that it should be 4-6", however, the contractor says 3" should suffice. Also, he is not planning on putting any gravel. He will put the rebars at the bottom. We are also planning on having a built-in grill and here we've been told again that atleast 12" is needed, but the contactor says 5" will do. What is the thickness that is needed for under the grill and for the rest of the patio area. Please help! Thanks, Vasu.