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Paver FAQs
Last Updated: 03/06/2017
Frequently Asked Questions about Concrete Pavers Why concrete pavers? Concrete pavers are the ideal product for freeze/thaw environments. Proper installation of the product results in a pavement that is rigid yet flexible. The joints between pavers allow the walkway, driveway, patio, etc. to move without cracking. In addition, they can be unzipped to allow for repairs or access to utilities. Unlike asphalt, pavers are virtually maintenance-free and do not need to be regularly sealed or replaced. By definition, concrete pavers have a minimum compressive strength of 8,000 psi (about 3 times stronger than regular poured concrete) and a maximum water absorption rate of 5%. Why are they called interlocking concrete pavers? It is the system that makes them interlocking concrete pavers, not necessarily the shape. When installed properly, the combination of the pavers, bedding sand, edge restraint and joint sand causes them to interlock, allowing them to work as a unified, flexible pavement. Does the color go all the way through the paver? Most are manufactured with a process that concentrates an extra dosage of cement and pigment on the wear layer. You'll never wear through this layer over the lifetime of the installation. Other pavers may have pigment throughout. How do I know how much stone base material and sand I'll need? As a rule of thumb, use a minimum of 3-5” of base material for walkways, 6-8” for patios, and 8-12” for driveways. The sand setting bed should be 1” thick. One ton of modified stone or sand will cover 100 square feet at 2” thick. Using a 10' x 10' (100 square feet) patio as an example, you would need 1/2 ton of sand for the setting bed (1” thick) and 3 tons of modified stone for the base (6” thick). You'll need some additional sand (about 5%) for the joints between the pavers. Should I use a fabric under my installation? When and where is it used? We recommend a separation fabric (e.g. Mirafi's 500X) under all paver installations. The fabric is laid on top of the compacted soil in the excavated area and keeps the aggregate base material from working its way into the soil subgrade. This is especially important where the soil contains a lot of clay. At a cost of pennies a square foot, the separation fabric provides an insurance policy against base failure. Please explain the sand setting bed. The material for the bedding layer should be coarse concrete sand. Do not use stone dust or screenings; it does not allow the pavers to seat properly and tends to break down over time. The sand should be an even 1” thick layer. Do not compact the sand setting bed. Do not mix portland cement into the sand used for the setting bed or the joints between pavers. It defeats the flexibility of the system and it cannot be cleaned off the surface of the pavers. Why pavers instead of patterned or stamped concrete? Patterned concrete pavements are merely slabs of concrete that are embossed with a pattern. Therefore, they are prone to the same problems with freeze/thaw cycles, namely cracking and spalling. Pavers won't crack or spall; you cannot expect the same for stamped concrete. Stamped concrete requires expansion joints every 10 feet or so which are very distracting in some patterns. Also, patterned concrete pavements don't allow access to underground utilities or the ability to make repairs. At virtually the same price per square foot installed, pavers are clearly a better choice. What are the advantages of sealing my pavers? Sealers offer three advantages: they help resist stains, enhance the color, and bind the sand in the joints to make it difficult for weeds to germinate. Sealers, however, are topical products and must be reapplied regularly (generally every 3-5 years). Only water-based sealers can be used in NJ and NYC. Will weeds grow between my pavers? Weeds and grass result from seeds or spores blowing into and lodging in the joint sand. This can be minimized by sealing the pavers or mixing a pre-emergent granular weed killer into the joint sand. If they do appear, a spot vegetation killer can be used and will not damage the pavers. What can I do if my pavers are stained or damaged? One of the advantages of pavers is that individual units can be removed and replaced in these situations. Remove the sand around the paver and then use two flat head screwdrivers to lift the paver out. Rocking the paver gently in a back and forth motion will facilitate removal. Can pavers be used for my driveway, too? Absolutely! 8 to 12” of compacted base material is recommended for residential driveways. A standard 2-3/8” thick paver can be used for light vehicular (cars and pickup trucks) applications. A herringbone pattern is most suitable in these situations. Tell me about snow removal and my pavers? Pavers can be plowed and shoveled the same as asphalt or concrete pavements. In fact, the chamfered edges and joints around the pavers promote melting of snow and ice. A plow with a rubber edge is recommended. Do not use sharp objects to chop ice as they can damage the pavers. Both sodium chloride (rock salt) and calcium chloride will remove snow and ice but can harm the pavers (and any concrete surface for that matter). Safe Thaw® ice melter is an effective and safe de-icer for your paving stone installation . Can I lay pavers over top of an existing concrete walkway? While not the preferred method, pavers can be laid on top of existing concrete walkways. Two issues must be addressed. First, the grade will be raised by about 3” (the thickness of the pavers plus the bedding sand). This is particularly critical if any doorways are involved. Secondly, if the existing concrete slab should raise or drop with freeze/thaw conditions the pavers will do the same. Can pavers be used for my pool deck? Not only do pavers make an attractive pool deck, but they also provide a slip resistant surface to walk on. Pavers actually are better than poured concrete around pools from the standpoint that the joints will take on moisture and leave the pavement cooler under foot. Like all products that are used outdoors, lighter colors will tend to stay cooler as they reflect the sunlight. Furthermore, bullnose pavers make a nice pool coping. Make sure the soil around the pool is well compacted before installing pavers. My new pavers have a white haze on them. What is it and how do I get rid of it? The white haze is most likely efflorescence which occurs when the natural salts in the raw materials settle on the surface of the paver. This is common with all masonry products. Surface moisture acts as a wick to draw out these salts. The best course of action is to do nothing; natural weathering will remove the efflorescence generally within 6-12 months. Chemicals specifically designed to remove efflorescence are available. They will only remove the surface salts and cannot stop the process. Carefully follow the directions if you decide to use these products. They are caustic in nature and can damage the pavers if used improperly. How can I remove mosses or molds from in between my pavers? Try Clorox diluted in water (10 parts water to 1 part Clorox). Be extremely careful not to get it on other plant material. Keep in mind there is nothing that will keep it from growing back if it is in a shady, damp area. For a more permanent solution, you will need to correct the moisture and shade problems that are encouraging the growth.

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