What sand should i use for block paving

Part 6: Re-sanding. Although the areas that were repaired see previous were re-jointed as part of that work, the bulk of the driveway has endured compromised joints since it was cleaned some days previously. Although it is unlikely that there are any truly empty joints, and despite the care taken during the cleaning process, most of the joints have been partially stripped of the critical sand jointing that gives this type of elemental pavement much of its strength and competence.

Empty joints It is important to appreciate that jointing sand is not there simply to fill the gaps between adjacent blocks: it provides the essential friction which then generates the horizontal and vertical interlock that allows those little blocks to carry such relatively big loads. Without the jointing sand, the pavement would, literally, fall apart, so it very definitely must be replaced. Of all the tasks that form part of this refurbishment project, this re-sanding of joints has to be the easiest.

The surface needs to be dry to ensure the kiln dried sand KDS sweeps across the blocks without getting stuck, and a decent medium bristle brush is ideal. So, it's nothing more complicated than scattering the KDS over the dry surface and then using the brush to push it around and into all those open joints, topping them up as you go. Unlike the jointing done immediately following pavement construction, this top-up jointing will not be rattled-in using a vibrating plate compactor.

Instead, we rely entirely on gravity to fill the joints, but bear in mind that, by and large, the joints are already filled to half or two-thirds depth and this exercise is merely topping-up, so no great effort is required. If large quantities of weeds have taken up residence in the joints, you may want to begin this entire project by declaring war on them. Before you remove any of the old sand, apply a non-selective herbicide. You will need to let this sit a few days before you can continue.

The difficulty with weeds is that simply pulling them out may not eliminate them. Weeds often have strong roots that travel below the pavers. Things like Bermuda grass form a whole colony making it tough to eliminate. The weed killer will not only kill what you see on the surface but put a hurting on what is still underground.

If you have a serious weed problem, you may want to pick up some of your pavers and see if there is an extensive mat of weed roots underneath. If this is the case, it is very likely that in time the weeds will reappear. Since weeds will grow through concrete in time, there is very little chance that a polymeric sand will stop them in an area with a high infestation.

Under normal weed conditions, one here and there, the process of removing the old sand will eliminate most of the weeds and deter them from returning. The biggest challenge you will face is how to avoid staining. Every polymeric sand that I know of will stain under the right conditions.

There are two keys to success here. The first is to make sure the pavers are dry. Not just the surface but most of the way through. The water will wick up through the pavers and cause stains. The same applies if you need to use a pressure washer to remove the sand that is left from the original installation.

They will stain no matter what you do. The second thing that is important is to remove ALL of the dust created when you put the sand down. After you have swept everything that you can into the joints, a leaf blower set on low and held at about a degree angle will gently remove excess dust. This dust is what causes the stains once it is wet.

The process of placing the sand also requires attention to detail. Pour the sand onto the pavers and sweep it into the joints. Using a broom handle or some other blunt object, tap on the pavers. This will cause the sand to consolidate.

If the paver is beveled the sand should be even with the bottom of the bevel. Using a small broom or brush carefully sweep all sand off the pavers. If you have access to a leaf blower, adjust to the lowest setting, hold the blower about waist high and blow excess dust from the pavers. Be careful that no one is standing immediately downwind.

Once ALL dust has been removed, you are ready to spray water. However, special care must be taken while cleaning off excess dust from pavers, especially if a leaf blower is used. It is very easy to blow the sand out of the joints if the blower is not angled properly. Additionally, closer observation is necessary when watering, as the false joints will become saturated faster than the full depth joints.

Thus, it may be necessary for you to apply more water to the full depth joints versus the false joints see section below on watering. You need to add enough water to saturate the sand but not so much that you float the polymers out of the sand. If this happens, you will see a white milky substance. Floating polymers will also cause staining. Spray for a few seconds, then stop and observe. If the joints continue to take water, keep spraying. The polymer will begin to set and no more water will penetrate.

The danger in not watering thoroughly is that the top will harden and the bottom will not. If this happens, it is only a matter of time before the sand at the bottom of the paver gives way and the top falls in. Compacted concrete sand is then placed on top of this.

A thin final layer of setting sand is the actual surface on which you place the pavers. Larger paving stones act like building footings. In other words, compacted sand can provide a sufficient base for a paver patio that's just going to have you walking across it.

The sand should be spread over a 4- to inch layer of crushed stone, which has been tamped into place. Once the sand is installed, moisten it and tamp it into place so it won't settle further. Kiln-dried sand is the best sand for block paving joints. It's an extremely fine sand that's been dried in a kiln to remove all the water before being used. Building sand is not used for the laying of block paving or paving slabs unless it is combined with cement and even this mixture can be too soft to lay paving slabs upon.

Grit sand should be used in the construction of a driveway or patio because it has a much greater strength to 'hold up' the material laid upon it. Repair sunken paving blocks. Clean the paving you have removed. Important — As you stack the paving bricks it's important that you give them a good clean with a small stiff brush to remove any 'stuck on' sand. Level up the uneven area with grit sand. Re-lay the block pavers. Compact the relaid paving. Apply kiln dried sand. You can protect the joint sand from washing out by sealing the paver surface.

Sealing restores the beauty of your pavers. The paver sealer also serves as glue between the joint sand particles hence holding them together, and preventing the sand from being washed away when it rains or during pressure washing. Fine fillings, like sand, will settle easily into the cracks between pavers , while larger fillings, like gravel, can add color to your patio.

You can even use moss to fill in pavers , for a natural look. Sand between pavers creates friction that locks everything together. Another option is polymeric sand, which is a specialty product that has water-activated polymer in it. After adding it to the paver joints, wet the polymeric sand to activate the polymer and harden the sand.

The sand used when building a paver patio or walk is a coarse builder's sand , with pieces ranging in size from 0. It may be called C, all-purpose or leveling sand.