Bituminous Base Primer
The Bituminous Base Primer is made from asphalt and solvent (also called thinner), and its mix ratio should be determined by the lab experiment of the factory. Before paving or laying the torch on asphalt or bitumen membrane for waterproofing or vapor barriers , the base layer should be coated with the Bituminous Primer to make the membrane strongly and firmly adhere to the base layer, which is also called the base layer treatment agent.
The base layer must be dry and clean before painting or brushing the base primer. It is not appropriate to construct in rainy, foggy, and dew weather. During the construction, use a brush to brush the details around the nodes, corners, etc., the coating of base primer should be uniform, the recommended thickness is about 0.15 ~ 0.20 ㎜, there must be no missing coating, exposed bottom, and pitting. Spray the second layer after the first layer is dry.
After spraying or brushing the base primer, the asphalt molecules in the primer will penetrate into the capillary pores of the base layer with the solvent. After the solvent volatilizes, the remaining asphalt combines with each other to condense and form a strong coating film.
The Main Function of the Bituminous Base Primer
1. Capillary pores of the base layer are closed, and the bitumen film closes the base layer so that the moisture above cannot penetrate, which becomes a waterproof layer and at the same time can block the penetration of water vapor below, thereby reducing the bubbling defects of the waterproof membrane.
2. Increase the adhesion between the waterproofing membrane and the base layer, that is, the adhesion power. The base primer penetrates into the base layer, which is equivalent to “asphalt nail” nailing into the base layer, so that the asphalt glue and the base layer are better and stronger.
3. Reconcile the affinity of the base layer and the waterproof layer, because the main component of the cement mortar is calcium silicate, the component of the asphalt is asphalt esters, the two are not compatible enough, the adhesion is not easy to firm, after the base primer is applied, It can make the bituminous glue stick better with the base layer and reduce the bulging and shelling of the waterproof membrane.
4. Conserve the base layer . Most time, the roof leveling layer is constructed in the rainy and humid seasons and regions, and it always in a rush period. When the cement mortar can be used for operation after the final setting, the slow volatile base primer is sprayed immediately to seal the base layer, so that the internal moisture is not easy to evaporate to achieve self-care . After the base primer dries, the waterproof membrane can be applied.