Landscaping & Design/Rock Quarry Patio


Hi Mark,
 I saw that you answered some questions about rock quarry for a patio. I have a question concerning a sealing issue as well. We recently had this put in. I don't know anything about it, so we trust the landscapers did what they were supposed to!

 They put sand over the top of the rock quarry and swept it into the cracks. Later they came back and told us they sealed it with another type of sand and they spread it in to the cracks and then wet it down. The lady said it should act almost like a rubber sealant. However, it never "rubberized" and it's really quite irritating because there is sand EVERYWHERE!! It tracks in to the house and gets all over our feet. I have tried to contact them with any suggestions to this problem, but they haven't gotten back to me. I'm wondering if you have any suggestions.

 It doesn't seem to me that they even sealed it. I saw in a previous answer that you don't recommend sealing it. With cracks being in between the rocks.. is that going to mess anything up? We couldn't grow grass in this area so that's why we decided to put in the patio.. it doesn't seem that adding grass between the cracks could be a solution. I'm just at a loss for what to do. I guess having the large cracks wouldn't hurt anything.. I just don't want our children to trip and fall. My biggest complaint is the massive amounts of sand I'm having to deal with.

Any suggestions are appreciated! Thank you SO much for your time!



Perhaps the binding agent added to the sand used failed or if a pre-mixed paving joint sand compound was used,perhaps it was not handled properly. The sand could be too fine and is now washing out. If what was used was some kind of semi-dry mortar mix,perhaps the mortar to water ratio was not right. A relatively coarse sand such as concrete sand would be more desirable than a finer sand in a larger joint. A fine sand can have a tendency to wash out because it will not bind as tightly as a coarse sand,although a binder can compensate for this tendency. A semi-dry mortar mix would be a cheaper option but may have less flexibility of movement than a sand mixed with an organic or synthetic binder. The paver joint material has to move as they expand and contract without cracking. Also,it takes a few passes with a thin layer of sand to get it properly swept in and compacted in the joints. It may be desirable to wet it down after a single pass and then come back the next day and sweep another layer in and then repeat the process. If the sand was swept in hurriedly and in 1 pass then it may not have settled properly.

A fine sand,such as masonry sand can be effective to seal joints where the joints are relatively narrow such as with brick or concrete pavers but I would not recommend it for a larger jointed stone installation. The bond of fine sand is weaker than coarse sand. Sand with a binder added has a superior bond.

The fact you have not been called back by the contractor is a big red flag and indicates that poor workmanship and poor materials were used. Situations like this illustrate how a designer can protect you. A designer can write specifications outlining exactly what type of materials are to be used and how they are to be handled and applied.

I question why the joint sand was placed in 2 layers. Seems it would have been better for one layer of either plain coarse sand or one layer of sand with a binding agent.

After removing the old sand,the following,listed from least expensive to most expensive, could be options for you:

Plants,such as creeping thyme,in the joints.

Coarse sand,such as concrete sand.

Semi-dry mortar mix or wet mortar mix.

Paver joint sand with an organic or synthetic binding agent. Or perhaps you could mix the existing sand with a binding agent.

Polymeric sand.

Hope this helps. Good luck.

Mark Harshman

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Design of landscape structures and design of planting arrangements in the landscape. I usually do not answer questions of a horticultural nature or about growing plants or gardening unless they are related to design. I will answer these questions at my discretion. I will answer maintenance questions at my discretion,usually when they are related to design. I am a landscape designer. I am not a contractor or a gardener. Although I will describe how something is built I do not provide detailed installation or construction instructions. Here are example categories of problems I can help you with: Design of residential walks,low walls,low retaining walls,fences,drainage systems,arbors,plant selection,xeriscapes (low water use landscapes),rain garden design,rain water harvesting,permeable paving,sustainable drainage. No advise on an architectural or engineering level. I DO NOT PERFORM ACTUAL DESIGN WORK THROUGH THIS SITE. I only provide suggestions and advice. For more comprehensive help check out my website at:


Landscape concept plan for a 30,000 square feet housing site. Involved site recon by pace measurements and photographs and a site analysis and a site analysis report and recommendations and a preliminary cost estimate. Design elements included canopy trees,shrub cover,accent flowers,trash receptacles,benches and planters. Landscape concept plan for a 7,000 square feet site for a community center. Involved site recon by tape measurements and photographs,a site analysis and the creation of 3 conceptual designs for the site. Work was done through a local professional design center. Design elements included tree garden,playground,sitting area,lawn,cooking area,lighting and concrete and brick paving. Landscape concept plan for a 3,000 square feet housing site. Involved site recon by tape measurements and photographs and a site analysis. Concluded in 3 concept designs for the site,shown at a formal presentation,a site analysis and recommendations. Work was done through a community volunteer program. Design elements included decks,a playground and fencing. Briefly as draftsman for landscape designer/gardener. Conceptual landscape design for residence. Involved site recon by tape and pace measurements and site analysis. Design included covered patio area,ground cover and flower beds. Two years experience as draftsman for transportation department in engineering firm and for engineering consultants to phone company. Duties consisted of plotting topography. Survey crew member. General assistant to surveyor. Work was done for U.S. Army and County Highway Department. No instrument work. Duties included tape measurement,holding graduated survey rod and plumb bob for sighting and clearing brush. Marketed Landscape Design Services. Brochure writing,promotional material and marketing graphics.

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From Civil Engineer: I am very impressed with your work and with the obvious thought you have put into the marketing of your venture. It was especially good to see a print of that job we discussed on the phone. I wish you much luck with the venture as I do with your plans for school. Im darn proud of you buddy. And by the way,when I get my license,maybe you will consider me for a consulting job down the road. I hope to get together with Rick sometime soon and I would really like to show him your stuff if its ok with you. From all these questions you ask I get the feeling that you are genuinely interested and have put alot of thought into the idea and process of landscape architecture and if you could possibly afford the cost I would urge you to take some classes in the areas you are most interested in. The subject is not so simple as it appears,mixing science and engineering with art and a certain amount of religion to create a comfortable and pleasing balance between man and nature. A thoughtful soul like yours can do this but it can be a lifes work getting it right.

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