# How much sub base for patio?



## Reiguy

Hey guys. I am getting ready to put a patio in my backyard. I have had them installed in other homes before but never did one myself. 

One question I have is about the sub base. From personal experience how many inches of crushed stone and sand should I use, before placing the pavers?

Thanks guys.


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## KUIPORNG

*I would like to know too*

book said minium 4 inches... for gravel and 1" for sand....

but my neighbour said that is way too much... and waste of money on gravel as well as waste of effort to dig and store the soil.... he said forget about the book.... 

I also suspect the trade people really put that much gravel ... as the less thickness is to their advantageous in terms of profit....

I am doing mine now and I use 4 inches....

would be nice if a trade people answer this question tell us the truth in contractors world....

I originally want to hire someone, but end up that guy is kind of busy and we don't want to push him around and we enjoy working on it ourselves you know it can be a family activity...


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## sevver

I did about 8" under mine, compacted in 4" lifts, and I went about 1' wider on each side than the width of what I was going to do. Then, I leveled out with sand, maybe an inch, maybe more, maybe less. I see the sand as something to easily level with, and once the pavers are on it, it would disperse the weight evenly. 

The only reason I did 8" though is because I had dug a pool at the same time, and it was too much to try to keep grade for the pool, and the paved area. I would go ahead with the 4" minimum though, especially if you get frost. It will allow your ground to be dryer potentially under the paved area and could prevent heaving. Mine is still relatively sound, although it is not a flat as it once was. The nice thing about pavers though is that the heaving seems to make hills instead of cracks.


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## KUIPORNG

*8 " gravel means somthing like 11" depth digging*

Did you remember how much gravel for the sq. footage of your project.... 

for my project of 600 sq.ft... I found out I requires 12 tons of gravel for 4" roughly from the internet calculator...

Do you minding sharing your real experience information...


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## sevver

I always just calculate it myself into cubic yards and then call the yard for tons. Each material is different. 

Square feet / 12 gets you to square feet an inch thick, then X by however many inches you want, then / again by 127 gets you into yards. When I did mine I just rounded it up a bit, which is good because I ended up needing it. 

Obviously you don't have to divide by 12 if you don't have an odd number. If it is 3" you want then divide by 4, then again divide by 27.


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## KUIPORNG

OK... let me try your formula, just because I got "A" in Maths in highschool....

600 / 12 * 4 / 127 ~ 2 

means 2 tons of gravel....

that doesn't sound right....


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## sevver

Typo, 27, not 127. Sorry My 1 yo is keeping me hopping...


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## KUIPORNG

so base on your formula it would be

600 / 12 * 4 / 27 ~ 8

8 tons of gravel.... mmm... somewhere in the internet I calculated 12 tons......

may be one more opinion from a different person will help.... well although I probably will confirm from the store where I bought the stuff anyway...


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## sevver

Well here goes, you have 600 square feet. Without doing anything to that, if you figure it at cubic feet, then it is 12 inches thick. So, at a foot thick, you have 600 cubic feet. 

Now, think of a 3 foot by 3 foot square. If you divide that into 1 foot squares, you have 9 on top, 9 on bottom, and 9 in the middle. that is 27

So, if you have 600 cubic feet at 1 foot thick, if you divide by 3, that gets you to how many cubic feet you have for real. 200, now if you divide that by 27, you will get the cubic yards.

This is in no way saying that one yard is equal to one ton. There will be different calculations for that. You should call your supplier and have them finish it off for you. There is alot in there to worry about, moisture content being the biggest factor. I have seen loads of stone come that is literally drenched with water. That is obviously going to be different then a dry load.


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## Reiguy

*hmmm*

So out of curiosity. The best place to get the crushed gravel would be from a supplier that has it in bulk opposed to buying bags at Lowes or something.

Who should I look for in the phone book for the gravel?​


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## sevver

I would say go for a landscape place. Unless you need enough for a six wheeler or a semi. Which is around 12 to 24 tons, if you need that much, just call the quarry, they have people waiting to make a run usually. If you need less, a landscaper will get it to you in a smaller dump truck or one ton dump. I would never buy it by the bag if I needed more than probably 20 bags or so. You have to really look at the price difference. 

My question is this, can you get crushed stone in the bag? I would use stone with fines in it, like road mix, for this situation, or else the sand could settle through eventually. I doubt it comes in a bag, but hey, I have been wrong before.


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## Reiguy

*hmm*

Cool thanks for the advice. I will be sure to call tomorrow.


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## concretemasonry

A 1" layer of sand for a setting bed if you are using interlocking pavers. If you are using something that does not interlock(with tight sand joints), then it depends on what kind of units you are laying.

If it is over 9" inlength or width, it not a true paving stone and really is just a stepping stone if it is a manufactured concrete unit. The installation procedure is also different.


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## Reiguy

*hmmm*

I had planned on purchasing some cobble stone pavers from Lowes. 

http://www.lowes.com/lowes/lkn?action=productDetail&productId=51410-215-51410&lpage=none

If anyone has any experience or reviews of them before I buy them. Let me know. 

Also I did get the pricing of some crushed gravel from a landscaping contractor.


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## KUIPORNG

*Grade of Sub-base*

http://www.pavingexpert.com/subbase.htm

check above UK web site for different grade on sub-base... price different on them 

wonder what is the terminology used here in North America for those different grades

DTP type 1
DTP type 2....etc.


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## Reiguy

*hmmm*

thanks man that was helpful. 

While looking through the page I tend to ask myself. . . . why do us Americans have to be different and not use the metric system. I know the conversion rates, but seriously. :laughing:


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## zol_Ca

well this was awhiel ago u guys were talking about it but for side walks and back patio id say u want atleast 3"stone base(5/8 traffic bond) 4" would be better because i doubt you guys are going to be using ultra base, it cost about a 1$ a sqft at 3" and it no one really use's it for interlocking brick only the one company i used to work for it allows drainage and it get stiff like concrete u order it from a concrete plant( lafarge ) is the only one i know of that sells it 3" of that is like putting down a 10" stone base we would use it in everything driveways patios an sidewalks. without it your interlocking brick will eventually no matter what u do will become un level in one spot or another and need to be fixed, driveways tend to get tire rutt's and this prevents it big time. im talking about a 10year time frame before u notice this shifting. if it was at my house be placing concrete, but the interlocking brick u want atleast 3-4" stone base traffic bond needs be compacted at 3" and then again after the extra inch if u go 4. then u would want 2" of HPB we dont use sand anymore you could use 1" of HBP but for and extra inch it dsnt cost that much more you place your brick on that HPB and use polymeric sand fill in all the cracks pack put more sand and sweep it pretty nice and blow any sand sitting on top left on the bricks this is important because u dont want any sand anywhere but in the cracks, becarefull not to blow alot of the sand out from in between the bricks and spray with water lightly once wait about 20mins when its dry and give it another light spray and you set. the sand will turn rock hard like concrete you get no weeds and lesser chance of bricks separating looking at around 20$ a bag for the sand (HPB) is a high performance Bedding you could us 1/4 clear they look almost the same but cost less only recommend the 1/4 if u can get ahold of lafarge and use ultra base. note if using ultra base and ur using thin stones under 2.5" thick a rubber mat under ur tamper whiel u compact is needed so the bricks wont crack. EXP 2yrs of interlocking 6 as a Concrete finisher.


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## concretemasonry

zol Ca -

Those suggestions could work for a patio in a mild climate. They would not be acceptable for a driveway, street or a major 40 acres industrial installation, so I would hate to see people get misled on something more important.

On these installation polymeric sand is not used and setting bed is 1" of concrete sand and the joint and surface applied sand is a fine sand (commonly mason sand). All of this is listed in the technical notes of the Interlocking Concrete Paving Institute (icpi.org?) that also in the North American group that certifies installers. All of the major CA paver producers are member and probably give you some assistance.

Dick


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