Name of the waterproofing method
|
Outline of the waterproofing method
|
Merits
|
Demerits |
| Asphalt waterproofing |
The waterproofing layer is formed by several sheets of asphalt roofing which are laminated and glued one by one with melted asphalt.
|
| (1) |
Once the melted asphalt cools, the waterproofing layer forms within a short time. |
| (2) |
The asphalt waterproofing can be used for various waterproofing specifications by changing the combination of type and number of sheets of roofing. |
| (3) |
The asphalt waterproofing achieves high watertightness reliability due to its laminated structure. If the rooftop is covered with concrete, it is possible to walk on the rooftop and use it for a longer period. |
|
| (1) |
Conventional asphalt waterproofing is sensitive to changes in temperature, leading to softening of the waterproofing layer in summer and brittleness in winter. |
| (2) |
Melted asphalt emits smoke and smells and may cause annoyance to neighbors. |
| (3) |
The method is increasingly difficult to use, since there is a growing shortage
of workers qualified to use asphalt heated to 300 °C. |
| (4) |
Installation of the edge of asphalt waterproofing is a complicated task. |
|
| Sheet waterproofing |
The waterproofing layer is formed by gluing and attaching 2 mm-thick vinyl chloride to the base. |
| (1) |
The waterproofing layer is available in a variety of colors. |
| (2) |
Careful walking is possible. |
| (3) |
The waterproofing sheeting provides higher and more reliable watertightness between the sheet joints than between rubber sheets. |
|
| (1) |
Vinyl chloride may emit dioxins when burned. |
| (2) |
The waterproofing sheet becomes detached from the base at the corners due
to heat contraction. The detachment may become worse at the sheet joints. |
|
| Waterproof coating (urethane type) |
The materials used are two liquid components. The two liquids are mixed
and stirred just before the start of construction. A prescribed amount
of the mixture is sprayed on the base, allowing a chemical reaction and
consequent hardening. A waterproofing layer with the prescribed thickness
is formed. In the standard specification, airflow-buffering sheets or reinforcement
materials are used together with the waterproofing layer. |
| (1) |
The waterproof coating can be applied to complex shapes, since it comes
in liquid form. |
| (2) |
There are no seams in the joints due to use of liquid. |
| (3) |
The rooftop can be used for sports, depending on the applied specifications. |
| (4) |
Construction can be done mechanically. |
| (5) |
The period of construction can be substantially shortened, using rapid
hardening-type liquid materials. |
|
| (1) |
Weather resistance depends on the top coating applied. |
| (2) |
Because two materials are used, mixing and stirring are necessary. |
| (3) |
It is difficult to control the thickness of the waterproofing layer. |
|
Topics 
The reliability of asphalt waterproofing is ensured by innovative new membrane technology
