You may have lost something in translation. All the words you use, bricks (clay bricks ?) concrete (sand aggregate cement and water?)mean different things to different people. Don't let them start before you have seen and agreed. Concrete, as described above, could be used for the first time on your job, I have never heard of it.

WHY does he want to put concrete in there? TO prevent weed seeds taking root? WHAT will be gained over sand? If he can't give a good reason, stick with sand.

The point of the base topped with sand and then bricks is that it is permeable. Filling the joints with mortar or concrete kind of defeats the purpose of this kind of paving, and I'm wondering if infrequent small gaps in the joints and/or runoff will cause erosion of the sand underneath under certain conditions.

I'd go with the sand, unless you can get the owner of the company to satisfactorily explain, in English, why they want to do this, and whether he will guarantee it. I'd also ask if he's completed other jobs like this, and if you can get the names of the satisfied customers who've been living with them for a while.

Your contractor wants to use a technique known as laying brick with dry mortar.

I haven't tried this, but I have been researching it for re-doing my front walkway with clay bricks. My builder installed an asphalt sidewalk at my house, which is settling and becoming a safety hazard.

The advantage of this method is that an open joint is possible, which is similar to the joint for bricks layed with wet mortar, and stronger than an open joint filled only with sand.

The dry mortar mix is 4 parts sand to one part portland cement.

If you are using true clay bricks or recycled clay bricks then they most likely will vary considerable in shape and deviate from a truely squared cast concrete paver. To compensate for this lack squareness and tightness an open joint method would be used with either sand, dry mortar, or wet mortar.

Older garden construction books will detail the method. Squared and tightly fitted pavers with swept sand are the most common techniques presented in more contemporary books.

I asked about these construction methods on another Distinguished Garden (DG) website, and the designers there didn't recommend the open joint methods.

I've done a couple of brick on sand jobs where the brick pattern left small joints. In such a design, dry-fit is the way to go, IMHO. I've also created a pattern, one where bricks were laid in a circular design, leaving gaps between bricks which went from zero to a half inch. With these larger gaps, I decided to use the dry mortar method - 1 part sand, 4 parts portland cement. It's a solid base, but when the rains of winter came, the cement went into solution with the rain water and left a whitish haze on the bricks. I'm just a DIY'er so don't know the solution, but if your brick design creates just small gaps between bricks, I'd go do sand only.

Bill

Isabella in Mass. gave a very complete answer to your question, and explains perfectly why a dry mortar/sand mix might be the preferred solution in your situation. I would guess that you inferred it was to be concrete from not understanding the spanish, but cemento=cement and concreto=concrete is not too difficult to translate... I personally wouldn't be too inclined to fault someone for not being able to fully explain the process in english,(especially if they do good work promptly), as I would also assume it could cost considerably more if he didn't have problems explaining fully in english.

I have personally used the dry mortar method for setting mexican pebbles on edge as banding between concrete pads, and it is much easier to do than a wet mortar mix, and just as durable. Usually you would only prefer to use the dry mortar mix for joints if the brick sizes are irregular, and won't fit tight. Also, it should be obvious if you chose a basket weave pattern with most clay brick, that the joints won't be even in both directions. I don't have the advantage of seeing your site to know if this makes more sense than straight sand in your situation. In any case, it is usually better to wet it immediately upon finishing set up to harden the mix. Dilute muriatic acid is usually used as a broom on wash to get rid of any cement film, it may take abit of scrubbing with a steel brush to remove it months later.

Not to change the subject, but I had this done and weeds are growing from between the bricks. I guess the sand between the bricks did not suppress the weeds. Is there something I can do to prevent this from happening besides using round-up?

kal2002-
I hope landscaping fabric was laid down before the sand bed on which your bricks lay. The fabric supresses growth from below, but you'll still get some small weeds and grasses growing from the joints where seeds lodge. I just pull the occasional weed from my patio - my neighbor uses his pressure washer to eliminate weeds from his patio cracks but as far as prevention goes, not sure that's possible without chemicals.

Bill

Thanks for the many responses. Sorry about the vagueness of the terminology. I was talking about mortar vs. sand when dry laying bricks. We're still in the middle of the project. It's been interesting.

Bahia, I'm glad you agree and would not be "inclined to fault someone for not being able to fully explain the process in english." These were not workers we obtained ourselves at a "shape-up" outside Home Depot. The contractor was hired at full-dollar, and these are workers he obtained. And I do fault the contractor for switching crews mid-project and substituting a crew who had an entirely different conception of what the project is. Fortunately, I have many bilingual neighbors who can help with translating.

Today we've made it clear we want a 2-inch bed of sand, as promised, and that they will have to dig deeper to accommodate that. Half inch of sand won't cut it. We've hired a lowboy Dumpster to put all the soil and broken concrete in, something the contractor promised to do but reneged on. We do not want them disposing of four 3x3 foot slabs of concrete from an old jacuzzi pad we inherited by BURYING them underneath where the patio is supposed to go, as they were doing yesterday. Just intuitively, that would seem to invite uneven settling of the patio.

This was all hashed out before work started with the first crew. The second crew was not properly informed by the contractor and was improvising with disposal of debris, since nobody wanted to cut into their profits by renting a lowboy. So these guys have to dig up the concrete, break it up, and they're piling it up on trees, wherever they can. Do twice the work, in other words. In record 97-degree heat. And they thought 1/2 inch of sand would be OK because where in hell is all that excavated dirt going to go with no lowboy to put it in?

Seemed like such a simple job, one we've done many times ourselves, except our backs aren't what they were 20 years ago. We think we're all on the same page. We'll see what happens.

Hi Bill,

No, unfortunately, there is no weed fabric underneath the bricks. Is that how most other people do it? I was told that the thick sand should suppress the weeds but not really.

kal2002, nope, sand doesn't suppress the weeds. I think they prefer it. I'm not up to date on the current state of landscape cloth. Maybe somebody can fill you in.

there was a post awhile back about the merits (or lack thereof) of landscape fabric. Seemed like most of us don't really use it or recommend it anymore, as it doesn't seem to work over time.

You all appear familiar with brick on sand. You've aroused my curiosity. I plan to expand portions of my patio with brick-on-sand and want to use mortar in the joints. I've already layed the bricks and plant to place the mortat this week. My reason for wanting mortar is the pool. My first set of bricks seem to allow sand to blow into the pool. Additionally, kids wet feet pick up sand for the pool.

However, we get frost and some good freezes every year (Northern KY). If I place mortar in the joints, will freezes cause cracking? Are there reasons I should avoid mortar?

As far as the landscape fabric, most of the weeds that grow from my paver patio in the front (no landscape fabric) and flagstone pathway (yes, landscape fabric) are seeds that have blown in on top. There are more weeds growing in the flagstone pathway where I used landscape fabric than on the paver patio where I didn't. And that's the same with the large foundation beds in the front and along the sides of my house. I went to a lot trouble putting landscape fabric and then mulch on top and there are just as many weeds in those beds WITH the landscape fabric, as are in the garden beds without.

Don't waste your time or money for the landscape fabric!

I also am interested in learning about possible reasons to avoid mortar. My husband and I just bought our first home a couple months ago. It has a small patio made with bricks recycled from the old gas chimney. There appears to be mortar between the bricks.

Over the last month, I've noticed an increasing of what looks like dirt/earth being pushed up between the bricks. At first I thought the kids might have been picking at the mortar, but it really looks like the earth is coming up from beneath the bricks in little piles. Could it be insects?

Faith it's probably ants creating tunnels underneath the paving. I have quite a bit of paving and the ants find it ideal habitat underneath. get a broom and sweep the sand back into the cracks but Ive found it hard getting rid of ants in paving, Ive tried granules and sprays and what not, but they just seem to move to another spot instead of leaving, although my climate is very dry which is great for the ants because the nests dont get disturbed or washed out by much rain.

faith, if acesjohn will tell us his/her experience with mortared (wet??) bricks on sand I would like to know too.

There is wet mortar or dry mortar approaches. Wet mortar is like building a brick wall with mortar between the joints. As this type of application is solid and generally inflexible, it requires a solid cement slab underneath it. Think about a tiled interior floor. If a tiled floor is built on a springy surface the joints and tiles will crack. Dry mortar on the other hand is applied in a very similar manner as sand, and is a more of a flexible system.

Both methods are satisfactory depending on what your use is for the area and more importantly the type of foundation used.

If you're worried about tracking in sand, a wet mortared approach will work, but so will a tight fitting paver block system.

The amount of sand tracked in from a well-built patio with tight joints will be very minimal.

Just use a door mat for any stray dirt or sand.