Laying a paver patio on a sloped site - Laying a paver patio on a sloped site

[pcommins]

I am an relatively unskilled do-it-yourselfer trying to lay a brick paver patio in my back yard, and I'm running into problems dealing with the natural slope of the location.

I've worked through every book and website I can get my hands on, but they all seem to deal with flat locations. Your website is amazing (thank you) and I think I may have found my answer in the kerbs or steps pages, but I'm just not sure. I would be very grateful for any help/confirmation that anyone can provide.

The site for the patio has a (mostly) level concrete sidewalk in good condition all along the top side of the patio site (near the house). Opposite to the sidewalk, about 8 feet away, is a shed. The ground runs down from the sidewalk to the shed and also from left to right (if you're standing on the sidewalk facing the shed). So one corner (on the right) is particularly low relative to the sidewalk.

If I run a level line representing the top of the patio, flush with the sidewalk on the highside and a 2% slope towards the shed, the top of the patio is 9 inches above grade (top of the existing earth) in the lowest corner. In the other corner, opposite the sidewalk, the line representing the top of the patio is only about 4 inches above grade.

Can you help me with the correct page on the website for containing the crushed stone on the low side? Do I need to build a kerb or a step? The patio will have only foot traffic.

I was really hoping to avoid mixing concrete (using a plastic edge kit). Any way to support the low side without some kind of restraint set in concrete? Could I just pile up and tamp down dirt to build up the low side, or would this just erode? If I use treated lumber nailed to deep-set stakes, will this be strong enough to hold everything together?

Finally, I was planning to use 4 inches of crushed stone for the base. If I dig 4 inches below grade on the low side, I'll have to add an additional 5 inches or so of stone on top of this 4 inch base to get up to the sand level. Can I save some money by not digging out the low side, or is it important that at least 4 inches of the crushed stone base is below ground?

Thanks,
Paul

[Tony McC]

In Britain and Ireland, we'd have no hesitation in using a concrete bedded retainer, but I note that you're from forrin climes, where concrete is not the preferred solution because of frost heave.

So, I reckon some form of staked timber retainer, along the lines of those shown on the Terracing page would be your best option.

Tamped earth isn't a feasible solution, unless you had tonnes of the stuff, so deep, deep stakes are what you'll need, probably a metre (similar to a yard plus tax) in length.

When it comes to the sub-base, again frost heave is a major consideration for pavement design in the northerly states of the US, so some frost cover is required. As we don't have these problems in these bejewelled islands, I don't keep myself up-to-date with the requirements and recommendations used over there, but I would hazard a guess that you'd need at least four of your quaint inches (100mm in Europe) below ground level, and to make sure that it is thoroughly compacted before placing any further stone.

We do have a couple of US contractors that like to call in for a cup of tea and a dash of British/Irish humour from time to time, and they may be able to help further. Look for Paverman Dan in the member list and send him a PM.

Failing that, the ICPI site, which is the main contractors organisation in North America, should be able to offer some advice - www.icpi.org

[pcommins]

Help me. I'm heart-broken.

After three weeks of back-breaking labor, stubbornly following all of Tony's excellent advice, step-by-step through the flowchart, over the objections of neighbors and wife (you're just a perfectionist, you don't need to dig that deep, you don't need gravel, any old sand will do, it's level enough already, etc. etc.), I finally finished my patio yesterday. It is perfectly flat and was so good looking I was stunned. My wife was thrilled. Celebrated and went to bed feeling as virtuous as a man can feel....

Went out this morning to snap a photo to post along with a my note of deep gratitude to Tony (including for the ICPI website address which had great technical specs for my small retaining wall and helped me to a local supplier of quality pavers). Went to sweep off the sand residue to capture the full beauty and -- lump in throat -- it won't come off. Tried to wash it off with a little water and, when wet, the patio looks great, but drys right back to the "washed out" sand-covered look.

Went back to the site and I think my pavers look like the "sand stained" picture on the jointing page. The rental center had no rubber mat for the Wacker plate and I didn't think I needed it. My pavers are chamfered, but I didn't realize this (thought "chamfered" meant having a tumbled pattern on top; didn't read carefully).

Before I ran the Wacker plate the second time (after jointing) I swept throughly and the compacter even seemed to pick up the little sand residue that was left (I remember because I used this effect to keep track of where I was on my plate passes). I'm pretty sure that after the plate compactor it looked ok.

After I returned the machine, I swept some more sand into the joints, this time using a larger push broom so that I was moving a good size heap of sand around. It was after this step that the pavers took on the washed out look, but I figured this was normal and would wash off. They were calling for rain so I just left it and figured I was done.

Also, I used the same concrete sand for jointing that I used for the bedding. I could not find Kiln-dried sand anywhere.

After not cutting a single corner, I fear that the two I cut at the end (not using kiln-dried sand or a plate protecting cover) have undone all of my work. Is it hopeless? Do I have to pull up all the pavers and replace to get back the color in my patio? Thanks.

[pcommins]

Some photies of my damaged brick. There is a unrepresentative yellowish tint to the photos -- that's a concrete sidewalk in the foreground.

[matt h]

looks like coarse sand staining, and you really do need kiln dried sand for jointing. I would remove jointing sand and replace with kiln dried personally, but you might get away with sealing the blocks, or use a colour wash then seal. suggest lutonlagerlout might better advise

[TheVictorianCobbleCo]

I woulld say that your unprotected whacker plate has done the damage. If it is cement stain, take a inconspicuous corner and wash one or 2 pavers with a 10:1 swimming pool acid wash - (ALWAYS add the acid to the water) rinse within a few mins with clean water and check the difference. Or - take a stiff hand brush and brush brisklly the top of 1 or 2 inconspiciously laid pavers - check to see what residue you brush off. Report back. Idont think you can repair damage done to thesurface but you might be able to minimise it.

[Tony McC]

Can you send me some hi-res photies?

I think it's just temporary sand staining and before charging ahead with Billy's recommendation of an acid wash (US pavers are dye-heavy and can often react badly to acid cleaning), I'd try power washing and/or leaving them to the weather for a couple of weeks. We have some spare rain in Britain at the moment that we'd gladly send over to you in order to help clean up the paving blocks!

[pcommins]

Thanks so much for all the prompt and helpful replies. I'm unable to get to the patio for a few days, but as soon as possible I'll try some scrubbing and get a high-res photo. Again, sincere thanks to all for answering my desperate plea...