What are the specific requirements for the construction of the mortar base?

Good or bad will affect the quality of the waterproof layer, and there are several requirements for the grassroots.

(1) The ratio of cement to sand

The number of mortars is too large, and it is easy to produce large cracks. In addition, cracks may be caused by other factors. If the full-stick method is used, the coils or coatings with low elongation will be broken due to the wide cracks. If the mortar number is too low, that is to say the strength is too low, although there will not be large cracks, too much dust will affect the adhesion. The ratio of cement to sand should be determined by the connection of the waterproof layer to the base. Sticky, stick stick construction, the ratio of 1:2 is appropriate. If full-stick and empty paving are used, the ratio is 1:3.

(2) Base thickness

The base thickness is related to roof panels and insulation. The overall cast-in-place concrete roofing board is 15-20mm thick; the thickness of the base layer is 20-30mm for the assembly of the roof plate; the thickness is only 30mm for the bulk insulation layer.

(3) Separation

In order to prevent excessive cracks in the grass-roots level, sub-lattice joints should be reserved with a vertical and horizontal spacing of not more than 6 m, preferably about 4 m. If the width of the seam is 5mm, there will be no seams if there is no insulation layer. The position of the dividing seam shall be located at the end of the support plate, ie the position of the wall or beam. If the slits are used as exhaust holes, the slit width should be 20mm.

(4) The mortar base shall be smoothed and compacted, and shall not be crisped, sanded, or peeled.

The grass-roots level is not even, and it is easy to produce tight joints when laying a coil.

(5) Grassroots moisture content

It is difficult to measure the moisture content of cement mortar that has been wiped, and there are no testing methods at home and abroad. Many manufacturers of waterproof materials indicate in the specification that the moisture content is of no practical significance. Can only be measured empirically

Whether it can be constructed or not, nobody knows what the moisture content is. The empirical method is to lay a 1 in. roll on the grass roots, open it after 3 hours, and construct it without a watermark.

The empty paving method does not care about the size of the water cuts. As long as the grass is solidified, it can be used by pedestrians. In the rainy season, it can be constructed by sweeping to Mingshui. Especially for floor waterproofing of underground structures, the coils need not be glued to the floor.

Do not consider the size of the moisture content.

(6) The base surface should be cleaned

Sand grains on the surface of the base are common and should be cleaned. A large sand may break through the waterproof layer. This is a common phenomenon. However, there is a small amount of floating ash on the surface of the base layer, which will not affect the construction quality. On the contrary, it can reduce some of the bond strength, and it is beneficial to the stripping of the coil.

(7) Yin Yang angle

Every corner of yin and yang should be painted with small rounded corners, depending on the type of roll. For example, a traditional felted asphalt mat has a radius of 100mm; if a modified bituminous coil is used as a waterproof layer, the radius is 50mm; if a synthetic polymer coil is used and the coated film is waterproof, the radius is 20mm.