The Brew Cabin

I've been all through the archives and current forums and seen nothing that resembles this.

I have a 400 sq ft patio created by the previous owner 20 years ago. The 8" x 16" blocks broke-up over time and the surface undulated to the point that it had to be replaced. He had put the patio on top of poly sheeting. I had assumed that he laid the surface on natural ground and was prepared to dig 4-5 inches to put in new base material. Then I discovered his amazing secret - he had used 4-5 inches of fine sand! No wonder the patio undulated over time.

So, not wanting to create extra work for myself if possible, and possibly save a few bucks, here's my new plan:

I want to meter-in bags of dry concrete to the sand, mix it in and level it off. I figure that the natural moisture should be enough to stiffen it up to the point where it will make a decent base. I plan to not over-indulge in concrete so as to allow for drainage. I plan to run a test patch before proceeding to make sure it works. Once the whole thing hardens enough, I will then add another inch or so of coarse sand before putting down the new pavers.

Is this a solid plan? Or do I need to start from scratch?

Mmmm. Difficult for me to comment as you're in the US where the construction methods are somewhat different to ours. So, if any of the following is complete bollocks (Quaint British/Irish term for 'claptrap'), can one of our USian visitors jump in and put me right?

If you add "dry concrete" (cement??) to the existing sand bedding, how will you ensure it's evenly and fully distributed to avoid any patches of non-bound sand remaining? Also, allowing around 35-50mm for a new sand laying course, will just 3-4 inches (75-100mm) of the cement-bound material be enough of a base to cope with the frost heave problems in your country?

Some of the specs I've seen for block paving on that side of the Atlantic are quite involved - 300mm or more (12 inches) of sub-base, along with capping layers and/or concrete slabs of 300mm or more. I'd be concerned about your proposed methodolgy on this side of the ocean, even if it were only for a patio area, so I'm extra concerned about how it would function over there.

Have you thought of asking a few contractors to come around, take a look and give you a price and a spec for them to do the work, just so you get a feel for what they, with their better understanding of Merkin ways, would consider to be a viable proposal?

Yes, I meant "Portland cement". Anyway, I wasn't expecting it to be perfectly even - but since the old patio held up for nearly twenty years, I was hoping that by stiffening the sand a bit, I might be able to get that much again. I planned to spread it as evenly as I could then spade it in and level it before it set. The local dealer wanted me to put down 5 inches of crusher run, followed by crusher dust. And that's what I had planned before I found the sand base.

Hi Jim,
I would suggest going with what you dealer recomended.
At least it would be easy digging removing the old fine sand.
CR6 stone is not all that expensive. Mainly the work of installing and compacting.
I don't believe the sand/cement will perform long term.
What part of the US are you in? I live in Maryland.
Charlie

I'm near Rochester, NY. Digging the sand will be easy. finding a place to dump it is the hard part. When I thought it was soil, I planned to spread it around the yard, fill in a few low spots, create some drainage berms. But now that it's sand - that presents a different problem. Maybe I can set up a roadside give-away.

Hey Jim,
My brother lives in Mahopac NY and I have spent time there.

Yea, Sometimes it is not easy to get rid of anything in NY as it seems that all trash/spoil is shipped out of state, very expensive business.

As far as losing the sand, it can always be used as a additive for cutting heavy clay soils for planting etc. Or a give away as you said.

Keep us posted as per your progress. What type of surface are you planning on installing? Block pavers? Flagstone? etc.
Charlie