Flagstone Patio Clues
What You Want to Know BEFORE You Do a Flagstone Patio Yourself!If I had a buck for every improperly installed flagstone patio I’ve seen, I’d be writing this on a lap top from El Baya De Navidad, Mexico, sipping a Bohemia Negra while I watch the waves roll in from the Pacific. But no one gave me a dollar for each viewing so I’m still in Tucson, Arizona – where folks seems to love this type of patio and I suppose Tucson loves to get it cheap since the wages here are some of the lowest in the nation.
I honestly believe the largest percentage of the mistakes I’ve seen come from recommendations made by the flagstone suppliers that just don’t know any better. I have had countless people tell me: “Well the flagstone company said, I didn’t need a concrete base.” Or “Isn’t concrete just cement and sand?” Here is one of many things that MUST be there in order to have a flagstone patio last more than a few years: I must be laid on concrete – 2500 PSI mix: 500 pounds cement to 1300 pounds of aggregate, sand and water per cubic yard of concrete. The concrete must be a minimum of 3.5 inches thick and the concrete must be reinforced. There are no options for a flagstone patio with mortar joints. I have seen thousands try to beat this simple system, all with dismal results. The joints crack, breathe crack again until in just a few short years you have literally tons of debris in lieu of a patio that was so pretty when it was first laid.
”The next most common line I hear is: “They were licensed so I thought I was covered, but when the registrar came out he said the work is only covered for two years.” Another trick some flagstone companies likes to do is unload thin flagstone – the problem is thin flagstone cracks very easily. Beware of this. With thin flagstone and thin cement your problems escalate very rapidly at the rate that the cement gets less than 3″ and the flagstone gets less than 1.5 inches your cracking and flagstone breakage is magnified exponentially.
I am not sure about where you live but in Tucson this must is a common misunderstanding. However, most people with the ambition to undertake this kind of project themselves have probably been exposed to at least some construction advice, if not some actual experience. Perhaps they’ve seen brick paving done on sand and think it makes sense to do flagstone that way, too! However the reality is: flagstone placed on sand is not the same as brick pavers placed on sand and here is why:
A flagstone patio incorporates mortar joints between the flagstone – common brick paving does not. The two concepts must be approached differently after the initial grading and compacting is done. When two masonry units are adhered together with mortar, the mortar is dependant upon a fpoundational stability to maintain it’s
adhesion. A proper joint is 3/8" to 3/4" wide and you cannot expect that little bit of adhesion to with stand “sheer” stress. So when a flagstone patio placed upon sand settles, wriggles or jogs any at all the adhesion is breached and a crack appears. Once you have a crack it will act as a relief for expanding and contracting during temperature changes as well as further and farther wriggling and jogging. As this movement happens over and over again, in time grains of dirt and sand get trapped in the crack, then during the next expansion period the pressure will push now against any partiulant lodged there, causing the crack to get larger until the mortar joint finally begins to actually crumble – unsightly to say the least. The mass resisting the strain of the flagstone, must out weigh the flagstone – simple physics – try putting one ton of flagstone in a vehicle that weighs less… enough said.
It can be even worse in more severe cases when there is only loose sand below the flagstone – we’ve replaced patios where after only a few months there were no sound mortar joints left at all. It is much more expensive to pull up the flagstone, re-grade, install a new proper base and then relay and grout the flagstone – as much as 3 times the original cost of doing it right the fist time.
To be sure your patio will still look beautiful long after your mortgage is paid off, a concrete base is MANDATORY. There is only one option that I have seen work. The sand was well compacted on a well compacted substrate. Then grass was planted in between the joints. When it grew and was kept trimmed (lots of weed eating!) it was quite attractive and as the grass grows the stone is bound even tighter by the roots of the grass. You could even do this and fill the joints with clay (that would slowly erode and need to be refilled every few years), but either of these options are far from "masonry" and will
not last the duration you would expect in a flagstone patio. Anything shy of proper flagstone installation is temporary at the very least.
Never feel embarrassed about asking the contractor about their techniques and/or the steps involved: It is your hard earned money. If your contractor becomes defensive when asked about their techniques you can bet they are skeptical about the system. If you can not afford to have a contractor build your patio properly (obviously this is alot of work and will cost more) go for the grass or clay option or better yet, go to a colored concrete or brick paver, both are cheaper.
The ignorance of craftsmen I have seen in my lifetime career, which started in 1972, is the primary reason I started writing the . If you want to
tackle your patio yourself, I have the for you (Stone Patio Secrets Revealed) it is easy to follow. If you are thinking about a patio and shopping bids, ask the right questions and then compare their price to one you can retrieve from my on-line estimators on: The Estimates Page
you will be glad you did.
Love, Light & Happy Building!
President: Jorsty, Inc. DBA- MonumentMasonry.com