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Frequently Asked Questions

June 30, 2015

Q. Will weeds and grass grow between the paver joints?

A. If you installed your concrete pavers with the recommended materials and methods, you will have created a sterile environment that will not allow weeds or grass to grow between the pavers. Seeds can blow into the top of the paver joints and weeds or grass can start growing in any organic material that has built up in the joints. In the event that this happens, you can pull the weeds as normally or apply a weed killer spray.

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 mason’s 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 mason’s 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 jobsite. 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 require 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 ICPI Tech Spec # 2, Construction of Interlocking Concrete Pavements.

If you have any specific questions, feel free to contact one of our knowledgeable sales representatives.

CastleLite Block-Proudly serving the San Francisco Bay Area(North Bay, South Bay, East Bay & Peninsula), Sacramento, Redding, Reno/Lake Tahoe, Monterey & surrounding areas.

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