Hello! new member with an urgent patio dilemma

[alice oliver]

Hello, Tony and Forum~

I've been reading everything I can find here on laying a flagstone patio the last few days, only to discover that what I have been calling flagstone, you all call "crazy paving." (!)

A new search on crazy paving has left me a bit discouraged and with more than a few questions. I think I've read all the archives and new posts and web pages dealing with this, but since I am in Montana, USA, and, since I have a different idea about what I want to do than what you generally advise, I hope you can help before I make a royal mess.

I am now ready to lay the rock on a sand base, but I am utterly confused about how to lay this rock to get the effect I want, even though I've read and read and read!

I'll try to give you enough background to be useful without running on too long. Thanks in advance for your time and help!!

I have acquired four tons of local, native blue flagstone (what we call flagstone here), with thicknesses from 1 1/2" to 2 1/2" (40 to 60 cm) and very irregular in shape and size. My garden is rather wild, and so I wanted the native stone for a certain effect: widely spaced natural rock, with lots of interesting plantings and creepers in between, mosses and thymes, etc.

here is a picture of the actual palettes of the rock:



We've excavated an 18' x 16' area down 4", or in British English: it's about 5 1/2 m x 5 m. down 10 cm. (I hope I got my math right, I'm reading out of a conversion table in the dictionary). The patio is adjacent to the back porch, so we graded it (the fall) down one inch (2.54 cm) per every 8 feet (2 1/2 m).

We compacted the soil, put in a surround of 4x4 cedar posts to hold the sand, laid down high quality weed fabric, and have filled the area with contractor's sand, or sharp sand.

Here's a couple of pictures that give an idea of the scope of the project:



That's me on the mini-bobcat we rented. the soil was very hard and compacted, so we needed this tool.



That's my husband compacting the bottom, which we leveled out and graded very nicely, I think.

So now it is full of sand, and I'm not sure what to do next.

I gather from reading your website that:

1. Crazy pavers are very difficult to lay well.

I have never done this before. We are complete DIYers and all planning has been done from reading and learning. I want to lay these well, and I want it to be beautiful and to last. If I could become a hotdogger on that bobcat in one day, I bet I can climb up the steep crazy paver learning curve, too.

2. Crazy pavers should be butted up closely to each other.

We only bought enough rock to space them very widely, and frankly, that is the look we want. We don't want a continuous hardscape. We want pavers interspersed with creeping plants. In the areas where we are putting our table and chairs, and our chaise, and our travel paths and hard use areas (like off the back porch) I plan to put the largest rocks, closer together, but the other areas the rocks will be more sparsely placed. I have drawn out a diagram for this on graph paper.

3. Crazy pavers need to be individually bedded.

OK, here is where I need some clarity: How do I know how much sand to put in if I am not tamping or screeding? (I'm not supposed to tamp or screed, right?) Do I just throw in the sand, rake it around, and then individually set each paver to the height of a drawn string? If I do that, then how will the rocks ever be firmly set in the sand?

Would it help to soak the sand with a sprinkler for an hour or so and leave it to consolidate on its own overnight? Or would that firm it up too much?

What I had planned to do was fill the bed entirely with sand (the bed is 3 1/2" deep), tamp down with a hand tamper, then screed to 1 3/4" deep, then lay all the rock at once, arranging artistically, then go back and adjust the heights of the rock. I take it that will not be a successful approach?

If I did tamp and screed, should the sand be screeded down to the level of the thickest rock, i.e. 2 1/2", and then all the other rocks raised up to meet the topline?

Is just plain sand not going to work? I see you mix in a little cement. I am in Montana, where it gets very cold, and it is a very dry climate (single digit humidity outside, often). I would think that any kind of mortar for crazy paving would be ill advised in this climate. The rocks, I would think, would need the flexibility to shift with the soil temperatures. Can you comment? And if I did use the cement, would that keep me from doing my plantings?

I had planned to fill in with a sand/dirt/compost mixture for the plants. Would that help more to set the stones firmly?

What kind of fill would be best? Some of these stones may be six inches to a foot apart (15 to 30 cm).

I'm holding off on laying the stones until I hear from you. I do not want to make a mess of this. We already have too much time, love, and effort, not to mention money, invested to bollux it up now.

Can you advise me as to the most efficient, stable, and lasting method to achieve the effect and use I am after?

Many thanks in advance, and apologies for the long post.

[alice oliver]

this is the effect i am looking for. spacing at least this wide. thanks again!

[Tony McC]

The problem I have is that the methods we use in Britain and Ireland are ideal for our unique climate, but they simply don't work as well in continental climates, because we can use cement with impunity (more or less) and you can't.

However, because I don't work in the US (or in central Europe), I have no real expertise in the methods used in those climates, and can only repeat what I am told by those that do work in such climates, which is, essentially, to eliminate cement from the laying course wherever possible.

The means your only option would be to lay your flagstones onto a bed of sand, but that's where the second problem appears: I've no experience wth US-ian sands, so I'm not sure how they perform. If I assume they are not too dissimilar to the sands we see in Britain and Ireland, then it would be a matter of preparing an individual bed, as outlined here and then consolidating the flagstone down to level using a runner mallet or a pavior's maul (if such things exist over there).

Just how these widely spaced flags would be held in place laterally is another problem. Obviously, you could pack more of the sand, or a sandy loam between the discrete pieces, and hope that holds until the vegetation starts to root and bind together the loose material.

[alice oliver]

tony,
thank you so much. i did not realize how dependent every aspect of your advice is on the climate and local materials.

i was going to lay the rock on a tamped, dampened, and screeded bed, until i read your advise about crazy pavers. i did experiment with just tamping and screeding in a sample area, and found the sand so consolidated that it would not allow the rock to tamp into it.

one contractor (who lives in southern california, a very different climate), did tell me that i should not tamp, but screed the sand down to the thickness of the thickest rock, water it, let set overnight, and build up the other rocks with sand, but i was afraid that doing that would mean unstable rocks. and this contractor doesn't specialize in working with stone.

i thought it would be better to screed the sand down to the smallest thickness of rock, and then press the rocks into the screeded--not tamped--sand. but the sand proved too consolidated after only screeding to do this method, either.

i haven't tried just raking and watering, letting sit, and then positioning rock, because i can't figure out how to know how much sand i've put in with this method.

simply raking and individually planting the rock does work to lay the bed, of course, but i am very concerned that it will all just collapse because of how dry it is here. the sand gets so dried out that it wouldn't hold much of anything unless it is consolidated, i think.

so....

is there a website like yours for conditions specific to north america? or, could you refer me to any reliable u.s. individuals here who might advise me?

or, could you recommend how i might inquire locally to find out how to do this based on local conditions and materials?

thank you ever so much. your website is quite wonderful and i am sure i am not alone in my appreciation.

[Tony McC]

It's a common misconception amongst many people that aren't fotunate enough to live in these sceptre'd isles, but our climate is a real one-off. Warrington, the nearest large town to where I live, is actually further north than Toronto, yet we rarely experience temperatures of less than -3C (25F). This winter, we had a full 1 inch of snow and it lasted a whole day before melting away! It's all because of the Gulf Stream, and it means we have a milder, wetter climate than you'd expect at this latitude.

All of which is why I make such a point of stating the website is primarily focussed on paving in Britain and Ireland. Nations with cold continental climates, such as those of northern Europe and northern North America, use different methods and materials because their climate is more extreme than ours: hotter in the summer, colder in the winter. They have to endure frist heave, which is almost unheard of on this side of the pond.

See...not just paving, but geography, too!

As for an equivalent site in North America, there really isn't one. This site is unique in that it is non-commercial; the nearest equivalent sites over there would be those that are spin-offs from the DIY TV shows...is there one called House Doctor or something like that? All the "advice" sites I've seen, have either been funded by manufacturers that want you to buy their products, contractors that want you to let them do the work, or TV shows that want to blind you with irrelevant adverts. The notion of a pro bono service such as this doesn't make sense to most of your countrymen, I'm afraid.

We do have a handful of US readers that like to hang out with the Tommys, Taffs, Jocks and Paddys in the Brew Cabin, but they are busy people and tend to call in only once a week or so, but I'll see if I can alert them to your plight.

[alice oliver]

many thanks again, tony.

actually, we do have an appreciation here for non-commercial, helpful sites. i belong to one that is about purchasing and maintaining pianos, and it is very consumer-driven, and not for the benefit of anyone making a profit.

however, such magnanimity evidently hasn't yet extended to the masonry trades.

your earlier post did give me the idea to take a chance and call a local rock yard and a local mason from the phone directory. they were incredibly generous and helpful, and both gave me the same exact advice:

simply rake the dry sand, dampen it only slightly as you work it, and individually bed each rock. evidently the stones are so heavy and dense that they will do all the work of consolidating the sand. the rock and the sand then develop a symbiotic relationship, each stabilizing the other.

after all the rocks are bedded and leveled, water the area, let the sand settle, and then fill in with good topsoil and compost, and plant with creepers immediately. as the plants establish their roots, they will stabilize the rocks and soil, which is what makes it possible to bed the stones so far apart!

much easier than tamping and screeding, and they assure me the rocks will not go anywhere. the sand is good drainage so there should not be frost heave, and the stones are too heavy to be moved by foot traffic.

i am delighted to have this information and am sharing it here in case future geographically challenged visitors need it.

again, wonderful site you have here, and thank you so much for your posts, which indirectly led to the solution.

[bobhughes]

Be nice to see a pic of the finished project.

Bob

[TarmacLady]

I think it might be useful to PM PavermanDan on this one -- Alice and hubby are a *very* long way from Dan (as in nearly two thousand miles!), but he might be able to make an educated guidance for them, as he'll no doubt be more familiar with US techniques and products...

I'm little to no help at all, as I'm nearly as far away from Alice as I could possible be and still be in the US...and my sub-tropical home climate and sand-and-limestone surroundings are absolutley NOWT like Montana!

[alice oliver]

thanks for the suggestions, tl. as it happens, the advice from the local masons is working quite well, and we should be done before the end of the summer :p

i will post pictures of the rock work in progress. it's going to be beautiful and i think quite durable, though it will take some time before the thyme, mint, lavender, and chamomile have filled in all the cracks.