Testing of Soil for Brickmaking

Testing soil:

  1. Get a handful of soil and add enough water to make it sticky.
  2. Mold it into balls and dry under the sun for 2 to 4 days.
  3. See whether the dried soil cracked or not. If it remains firm and hard the soil is clay.
  4. Test another one with this procedure.

Conduct another test by molding 4″ x 10″ x 2″ and burn with rice husk for one week. Good clay when dried by this method will sound metallic when tapped.


There are three (3) types of manufacturing methods for bricks:

  1. Soft-mud
  2. Soft-mud with repressing machine
  3. Mechanical method

Methods 1 and 2 are most suited for cottage industry. They are manually generated and require only a small capital.

Method 3 used machines for raw material processing and farming. Even if most of the machine can be made it still needs a big capital investment.


  1. Raw clay is left in the open for stock piling with a duration of about two (2) months or until the clay disintegrates thru the action of sun and rain.
  2. The disintegrated clay is brought to the processing area. Sandy clay, plastic clay and sand are mixed in their proper proportions. Water is added to combine clay mixture.
  3. Knead either by hand or foot for about three (3) hours.
  4. After kneading, the clay should be aged for two (2) days to get a homogeneous mixture. Aging distributes its workability and lessening the possibility of cracking during drying and firing.
  5. Form the clay into a wooden mold.
  6. The formed bricks from the mold are then placed on a pallet and allowed to dry to leather hardness for not more than two (2) days.
  7. The leather hard bricks are retouched to remove the finger marks and scratches due to forming and handling. The retouching work can either be done by skillful hand manipulation or by machine for better and faster finishing.
  8. Retouched bricks are kept in the drying area until they are completely and uniformly dried. The drying takes about two (2) weeks during dry season and four (4) weeks on a rainy season.
  9. When dried, put the clay in improvised kiln. Arrange them loosely and pour rice hulls in between the spaces.
  10. Set fire from the bottom. Baking process takes one week.

For more information, contact:

Dept. of Science and Technology
Rm. 303 DOST Bldg., DOST Complex,
Gen. Santos Ave., Bicutan, Taguig City 1631
Telephone Nos: (632) 837-20-71 to 82
Web: www.dost.gov.ph

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