QUIKRETE® Veneer Stone Mortar is a construction-grade mortar mix. Available in 60 lb (27.2 kg), 80 lb (36.3 kg) bags, and in 3000 lb. Dry or windy.
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Q: I spoke to several different contractors and each one has a different method of installation. How do I know which method is right?A: There are three basic types of installations; RCA or crushed stone, Concrete and Dry pack, which is a mixture of sand and Portland cement. However there is only one method approved by all paver manufacturers and that's the RCA (crushed stone) method. Pavers are designed to be installed as a 'Flexible' system which allows them to expand and contract as a system during freeze thaw cycles. Placing pavers on a ridged base does not allow the pavers to expand and contract properly during freeze thaw cycles and may cause the pavement to fail prematurely. So when a contractor claims that he has been installing pavers on a ridged system (concrete or dry pack) for 30 years and has NEVER had any problems, think about the condition of the concrete or asphalt system that you are replacing and ask yourself if you want that type of system under your new paver project.
The old ridged system didn't survive 30 years of freeze thaw cycles, do you think it will survive the next 30-20 or even 10 years without heaving or cracking, causing your new pavement to fail. Pavers installed on a RCA base actually have a higher load bearing capacity than concrete or asphalt because they spread the load over a greater surface area. Q: Are there any specific guidelines to follow when installing pavers?A: Yes Industry guidelines have been created by an organization known as ICPI (Interlocking Concrete Pavement Institute). ICPI guidelines were created to protect the consumer by leveling the playing field from one contractor to the next.
The best way to understand the value of this is to make a comparison, for example; Do you hire any plumber or do you hire a 'Licensed plumber? An ICPI 'Certified' installer should always be used. ICPI set the Industry standards for the proper installation of Interlocking Concrete Pavers. All paver manufacturers require that their products be installed in accordance with ICPI standards and guidelines by an ICPI certified installer to qualify for their Lifetime warranties. Q: I have an in-ground sprinkler system or would like to install a new sprinkler system is that ok?A: Having or installing an in-ground sprinkler system is fine, however a good contractor should relocate an existing system or install a new system in such a way that they system does not saturate the paved area. Excess amounts of water are detrimental to any type of pavement, they can cause an over-saturation of the bedding sand or base material and potentially cause a joint sand washout. Obviously nothing can be done about the amount of rain water your pavers will receive but a conscientious contractor can control the water from a sprinkler system by diverting the spray nozzles away from any paved areas thus prevent any over-saturation of the area and prevent any potential water damage.
Q: Should I seal the pavers?A: Yes, even though pavers are extremely durable, it is highly recommended, but not required. Sealing, will enhance the color and prevent staining. Most manufacturers recommend that you allow a minimum of 60-90 days after completion of the installation before sealing or until there are no more signs of efflorescence.
A more realistic time frame is closer to one year. Weather conditions and the amount of calcium hydroxide in the material will determine how long you will have to wait before all signs of efflorescence are gone and the pavers can be safely sealed. Also if the pavers are placed on a concrete or dry-pack base there will be a substantial increase in efflorescence. The additional calcium hydroxide trapped in the concrete or dry-pack must pass through the paver to the surface and then be removed either naturally or chemically. This additional process can increase the waiting period before the pavers may be sealed by 2 to 3 years before all signs of efflorescence are gone and the pavers can be safely sealed. Q: How can I minimize sand washing out of the joints and also minimize weed growth?A: There are several types of joint sand stabilizers available on the market today.
The best method to prevent wash out and minimize weed growth is the application of Polymeric joint sand. There are also liquid sealers that also act as joint sand stabilizers that can be applied directly over a typical joint sand application. The best alternative should be determined by the contractor, considering application method, experience, manufacturer's recommendations, job conditions and budget. Q: How do you go about laying paver next to a new foundation?
Do you need a special fill? Do you need to wait a certain period?A: Installing any new pavement next to a new foundation can always be tricky. Typically, new foundations are not back filled in layers and rarely compacted throughout. As a result, these areas are prone to settlement. A paver contractor needs to evaluate every situation on a case by case scenario. To encourage settlement of the soil before construction, some contractors will attach a pipe with a high pressure nozzle to the end of a hose and stick it in the ground at regular intervals around the foundation.
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This is then followed by compaction with a vibratory plate compactor. Geo-textile fabric should also be used to ensure a durable and long lasting pavement. Never start laying pavers until the sub grade and base are compacted to ICPI standards. Q: Why are screening and stone dust not recommended for the bedding layer?A: Screenings have excessive amounts of fines (passing the No.
200 screen), which compromises the ability to bear and distribute loads. These small particles hold excessive amounts of water, causing the bedding layer to become saturated. This liquefied layer then becomes unstable and can even pump out of the joints. Properly graded course multi grained sands conforming to ASTM C33 and CSA A23.1 will perform better over time.
This type of sand is readily available from your local supplier. Most suppliers may refer to this product as washed concrete sand.
Ask your supplier for confirmation from the quarry that this material complies with the ASTM or CSA, specification especially regarding the amount passing the number 200 sieve. It is recommended that the maximum amount passing this sieve is 1%. Q: Can bedding sand be used for joint sand?A: Yes, however a contractor needs to remember that washed concrete sand meeting the gradation requirements of ASTM C33 and CSA A23.1 is the only material the ICPI recommends for the setting bed.
This being the case, some of the largest particles in the sand may be more difficult to sweep and compact into the joints. Still, some contractors prefer to use the bedding sand material for their jointing material since it means having one less material to control on a job site and they also feel that they achieve better interlock between the pavers.There are some alternatives to consider. ASTM C-144 and CSA 179 graded masons sand contains more fine particles and tend to fill the joints faster, making final compaction less time consuming. Both materials are approved alternatives by ICPI.
Using masons sand makes sense if the time saved sweeping and compacting the sand into the joints outweighs the costs and inconvenience of having two kinds of sand at the job site. If not, then consider using bedding sand.
Some contractors feel that finer sands create tighter, less permeable joints.A third alternative is prepackaged Polymeric sand. When activated with water according to manufacturers instructions, this sand will harden, inhibiting weed growth, insect infestation, and sand run off from the joints. Generally, Polymeric joint sands tend to cost more than C-33 washed concrete sand and masons sand, and requires extra steps and time, so this should also be estimated into the project costs accordingly.Whatever the final decision may be, the ICPI does NOT recommend using stone dust, limestone screenings or other materials that do not conform to either C-33 or C-144 gradation specifications. For more information on joint sands, refer to. Q: Don't concrete pavers cost more than ready mix concrete or asphalt?A: The initial costs of segmental pavements over concrete or asphalt may be more, but it has been shown that the life cycle cost of an interlocking concrete pavement system over a 40 year period is actually less. This is because pavers make up a maintenance free pavement.
Because of the system of sand filled joints, unlike concrete or asphalt pavements, an interlocking concrete pavement will not crack. If there is maintenance that needs to be performed underneath the pavement, pavers can be easily unzipped then reinstated when the work is done- as opposed to noisy and messy demolition, disposal and replacement of concrete or asphalt. Stains are easily treated as most pavers can either be cleaned with special cleaners or easily replaced. Even in the short run, there are many advantages to using concrete pavers. Unlike asphalt or concrete, which need time to dry or cure once laid, pavers can be enjoyed as soon as they are installed.
Finally, adding in the benefits of many more color and design choices available, it is easy to see why pavers offer the best value. Q: What are the differences between American and Canadian standards for pavers?A: There are two sets of standards commonly used for pavers manufactured in North America: in the United States, it's referred to as ASTM-936, and the Canadian version is listed as CSA-A231.2.
While all the differences are too numerous to list here, there are two very important ones worth noting.First is freeze-thaw durability testing. ASTM-936 requires that units shall have no breakage or more than 1% dry mass loss after 50 freeze-thaw cycles in water as tested per ASTM C-67. With some exceptions the Canadian test is similar but with one important addition: the pavers are freeze-thawed in 3% saline solution to resemble the deterioration caused by de-icing salts.A second difference is ASTM-936 requires that the compressive test strength of the test specimens to be at least 8000 psi.
And that no sample test under 7200 psi. The Canadian standard allows for the average compressive strength psi. Of the samples to be 50 Mpa. (7250 psi.), with no unit below 45 Mpa. The difference is that the Canadians test using a 1:1:1 dimensioned cube that saw cut out of the paver itself; while the ASTM standard allows for full or one-half units to be tested (minor variations are made for non-rectangular/square pavers). Many of the remaining differences involve the number of samples used, the frequency of the tests, and other details in the execution of both tests.
To learn more about both ASTM-936 and CSA-A231.2-95, please contact the ICPI. Q: In order to prevent scuffing, is it necessary to protect the surface of concrete pavers from a plate compactor?A: Depending on the type of paver used, some contractors use sand or geo-textile as a protective layer between the plate and the surface of the pavers. Protective mats for plate compactors are also available and have proven to be the best method. There is no specific guideline from the ICPI for this, please contact the paver manufacturer for specific recommendations for their product.
Q: I recently removed old pavement, and there is already stone underneath. If properly compacted, can I lay pavers over it?A: This is not usually recommended. If the existing pavement is rutted, deformed, uneven or severely damaged, the base or sub-grade underneath the original installation is likely inadequate. Remember that the sub-grade and base are the most important part of an interlocking concrete pavement. Interlocking concrete pavers are designed to be installed as a flexible pavement, and as such, rely on load distribution in the base and adequate support from the soil sub-grade. Sometimes the stresses on the pavement are from below, especially in freeze thaw areas of the country, so even residential patios and sidewalks need to have a proper base. ICPI recommends a minimum base thickness of 4 inches (100 mm) for residential patios and walkways and 6 inches (150 mm) for driveways in non freeze thaw areas.
In colder climates these base thickness are increased and most contractors will use 6 and 10 inches (150 mm and 250 mm) respectively. Gradation is another factor. The ICPI only recommends the use of base material meeting gradation requirements of ASTM-D2940 with 6 to 12% passing the no. 200 (80 micron) sieve. Remember the base installation is the most important segment of the entire installation process, use of the proper materials and installation practices are essential to achieving the most durable and longest lasting pavement available. Q: What is that white haze on the surface of the paver?A: Efflorescence, it's a naturally occurring condition in all concrete products and is usually more pronounced with darker colors.
All concrete products contain cement which produces Lime or water soluble calcium oxide. Lime can also be in the bedding sand, aggregate base materials, or soil. Although concrete pavers are solid, strong, and very dense, they contain millions of microscopic capillaries that run from the interior to the surface. Moisture from rain, sprinkler systems, underground sources, poor site drainage, or dew enters these microscopic capillaries. Calcium oxide inside the paver reacts with the water in the capillaries and forms calcium hydroxide. This rises to the surface, reacts with the carbon dioxide in the air, and forms a white haze of calcium carbonate.
When moisture on the surface of the pavers evaporates, the white haze of efflorescence becomes visible. Efflorescence will go away naturally over time when the supply of calcium hydroxide in the concrete paver is exhausted. Typically efflorescence will stop developing in approximately 12-24 months depending on moisture and weather conditions. Q: Can efflorescence be removed without the wait?A: Most paver manufacturers put chemical additives into the concrete mixture to reduce the likelihood of efflorescence.
In most cases, they do the job. Completely eliminating the chance of efflorescence, however, isn't possible because it's a natural byproduct of hardened concrete. Efflorescence may be cleaned with commercially available cleaners specially formulated specifically for concrete pavers. Cleaning should be performed as soon as the efflorescence has appeared. It may reappear if any calcium hydroxide is still available in the concrete paver. The chemicals only remove the efflorescence from the surface of the paver, any remaining calcium hydroxide contained inside the paver will need to come to the surface and additional applications of the chemical cleaner may be required.Note: pavers should not be sealed until all evidence of efflorescence is gone.
Sealing prior to this will cause the efflorescence to be trapped under the sealer and the surface of the paver will turn white.For more information on efflorescence, refer to at their web site. Q: What about cleaning? Can I pressure wash my pavers?A: Pressure washing can be done but is not recommended to clean pavers for a few reasons; pavers can be damaged or marked if too much pressure is applied. An excessive amount of water pressure can actually embed dirt particles into the pavers surface, remove joint sand and increase efflorescence.
The preferred method is to chemically clean the pavers. Different cleaners are available for all types of stains including oil, rust, paint tar rubber and efflorescence. Q: Off the record, just using a ballpark, what is the going rate per square foot for installing pavers in my area?A: While tempting, bidding projects by the square foot (sometimes even before seeing the project!) is a recipe for disaster for contractors. Every job is different, and so is every contractor.
A successful contractor bids their company's price for a specific job, using labor hours for each job function and their own markups for overhead and profit. They do not quote square foot pricing simply based on competitive rates. Q: How long does it take to install pavers?A: Every installation is different and needs to be evaluated by an experienced contractor. There are a lot of factors to consider when determining how long a project may take such as: the size and scope of the project, placement of required materials, access for machinery, work flow, parking for construction vehicles as well as unpredictable weather conditions. All of these factors contribute to the length of the project and need to be determined on a per job basis. Due to unforeseen circumstances exact times for start dates, duration and completion dates cannot be given, these are usually estimated. We would greatly appreciate any comments or questions that were not covered in this section.The feedback and or questions that you provide will help us keep our FAQ's section as up to date as possible.
ANSWER ANSWER - It is hard to see exactly what they did. Your message says “photo thin set 1/16” is on the floor, 1.5” to 2.5” of mortar mix with less than 90% coverage, and thin-set 1/16” on the back of the tile.”That sounds like you are saying that the mortar bed only got 90% contact, which it should be 100% as should the thin-set.It looks like they are doing a wet set method where they put down the mortar and set the tile as they go rather than pre-floating and setting the tile the next day. Wet setting is ok, but it doesn’t look like they are doing it correctly.The mortar looks too wet.
It might not be fat mud (very wet), but it isn’t deck mud or drypack as it should be. The 4:1 sand to cement mortar should be mixed to a consistency so it looks damp and not wet. They should be able to take a hand full and squeeze it and it stays in the shape of a ball.They should be applying the thin-set to the substrate just before applying the mortar. They can make the thin-set wet enough to apply with a plaster’s brush, which is called a slurry bond coat.
They then apply the dry-pack mortar and compact it thoroughly with a wood float or magnesium float. Then they apply another slurry bond coat to the mortar bed surface and the back of the tile that is at least 1/16” thick to bond the tile to the mortar bed. They should achieve 100% mortar surface that is flat and 100% thin-set coverage. The wet set method makes it easy to get a 100% contact.The mortar bed method is considered a superior method to the thin-set method if done correctly. That is because you can compensate for the irregularities in the substrate and be able to achieve a perfectly flat surface that will allow you to avoid other problems.They could have used self-leveling if done correctly. Floor mud should be a dry pack mortar that I referenced.
Some installers use fat mud (wet) that isn’t per industry standards because you can’t compact it and it will tend to shrink excessively.The thin-set application for regular thin-set can’t be thinner than 3/32” thick and can’t be thicker than ¼” thick. If you have a tile that is irregular in thickness or has warpage you could use a Large and Heavy Thin-set that will allow the installer to go up to a maximum of ½” thick thin-set. Although when doing a wet set method you can apply a slurry bond coat that is as thin as 1/16” both under the mortar bed and on top of the mortar bed and on the back of the tile.Mortar bed methods normally require minimum 0.75” thick up to 2” for bonded mortar beds and thicker for heavy duty applications that require other provisions. Non-bonded mortar beds require a cleavage membrane under the mortar bed and require wire reinforcement suspended in the mortar bed between 1/3 and ½ the thickness.In all cases the key is whether it is being installed correctly and per industry standards.
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