MuirView Design
12-05-2007, 09:01 PM
I was reading this online and thought I'd share. I was wondering if we could collectively come up with a similar checklist for hardscaping.
Project planning for cold-weather masonry work should include the following measures:
Think ahead. Have the proper equipment, manpower and protective measures in place well ahead of time.
All masonry materials should be completely covered to prevent wetting by rain or snow.
The top of all walls not enclosed or sheltered should be covered with a strong weather-resistive material at the end of each workday. Partially completed walls should be covered at all times when construction is not in progress. The cover should be draped over the wall and extend a minimum of two feet out from both sides and securely held in place.
Never use wet or frozen materials. Only use dry, frost-free masonry units and sand.
The optimum mortar temperature has been found to be 70 degrees F +/- 10 degrees. The selected mixing temperature should be maintained within 10 degrees F.
At air temperatures of 40 degrees F to 32 degrees F: Sand and mixing water should be heated to produce mortar temperatures between 40 degrees F and 120 degrees F. Completed masonry walls and raw materials should be protected from rain or snow for 24 hours after construction by covering with weather-resistive membrane materials.
At air temperatures of 32 degrees F to 20 degrees F: Sand and mixing water should be heated to produce mortar temperatures between 40 degrees F and 120 degrees F. Maintain mortar temperatures on boards above freezing. Completed masonry walls should be kept above freezing for at least 24 hours after construction by providing weather-proof enclosures and auxiliary heat (when necessary).
At air temperature of 25 degrees F to 20 degrees F: Sand and mixing water should be heated to produce mortar temperatures between 40 degrees F and 120 degrees F. Maintain mortar temperatures on boards above freezing. Salamanders or other sources of heat should be used on both sides of walls under construction. Windbreakers should be employed when wind speeds exceed 15 mph. Completed masonry walls should be kept above freezing for at least 24 hours after construction by providing weather-proof enclosures and auxiliary heat (when necessary).
At air temperature of 20 degrees F and below: Sand and mixing water should be heated to provide mortar temperatures between 40 degrees F and 120 degrees F. Enclosure and auxiliary heat should be provided to maintain air temperatures above 32 degrees F around all walls and materials. Temperature of units when laid should be not less than 20 degrees F. Completed masonry walls should be kept above freezing for at least 24 hours after construction.
When using artificial heat, make sure all exhaust gases are vented to the outside. Carbon dioxide from open salamanders, gasoline engines, generators or mixer engines may cause a chemical reaction known as carbonation which significantly reduces the strength and hardness of masonry surfaces.
Admixtures such as antifreezes and accelerators are often encountered in cold-weather masonry construction. Most commercially-available masonry "antifreeze" admixtures are actually accelerators rather than freezing-point depressants. These may negatively impact masonry bond and compressive strengths if used in significant amounts. Calcium chloride is the most commonly used mortar accelerator. If used, it is recommended that it be limited to no more than 2% of the portland cement in the mortar by weight.
Source: http://kuhlman-corp.com/COLDmasonry.html
Project planning for cold-weather masonry work should include the following measures:
Think ahead. Have the proper equipment, manpower and protective measures in place well ahead of time.
All masonry materials should be completely covered to prevent wetting by rain or snow.
The top of all walls not enclosed or sheltered should be covered with a strong weather-resistive material at the end of each workday. Partially completed walls should be covered at all times when construction is not in progress. The cover should be draped over the wall and extend a minimum of two feet out from both sides and securely held in place.
Never use wet or frozen materials. Only use dry, frost-free masonry units and sand.
The optimum mortar temperature has been found to be 70 degrees F +/- 10 degrees. The selected mixing temperature should be maintained within 10 degrees F.
At air temperatures of 40 degrees F to 32 degrees F: Sand and mixing water should be heated to produce mortar temperatures between 40 degrees F and 120 degrees F. Completed masonry walls and raw materials should be protected from rain or snow for 24 hours after construction by covering with weather-resistive membrane materials.
At air temperatures of 32 degrees F to 20 degrees F: Sand and mixing water should be heated to produce mortar temperatures between 40 degrees F and 120 degrees F. Maintain mortar temperatures on boards above freezing. Completed masonry walls should be kept above freezing for at least 24 hours after construction by providing weather-proof enclosures and auxiliary heat (when necessary).
At air temperature of 25 degrees F to 20 degrees F: Sand and mixing water should be heated to produce mortar temperatures between 40 degrees F and 120 degrees F. Maintain mortar temperatures on boards above freezing. Salamanders or other sources of heat should be used on both sides of walls under construction. Windbreakers should be employed when wind speeds exceed 15 mph. Completed masonry walls should be kept above freezing for at least 24 hours after construction by providing weather-proof enclosures and auxiliary heat (when necessary).
At air temperature of 20 degrees F and below: Sand and mixing water should be heated to provide mortar temperatures between 40 degrees F and 120 degrees F. Enclosure and auxiliary heat should be provided to maintain air temperatures above 32 degrees F around all walls and materials. Temperature of units when laid should be not less than 20 degrees F. Completed masonry walls should be kept above freezing for at least 24 hours after construction.
When using artificial heat, make sure all exhaust gases are vented to the outside. Carbon dioxide from open salamanders, gasoline engines, generators or mixer engines may cause a chemical reaction known as carbonation which significantly reduces the strength and hardness of masonry surfaces.
Admixtures such as antifreezes and accelerators are often encountered in cold-weather masonry construction. Most commercially-available masonry "antifreeze" admixtures are actually accelerators rather than freezing-point depressants. These may negatively impact masonry bond and compressive strengths if used in significant amounts. Calcium chloride is the most commonly used mortar accelerator. If used, it is recommended that it be limited to no more than 2% of the portland cement in the mortar by weight.
Source: http://kuhlman-corp.com/COLDmasonry.html