Page 312 - Construction Waterproofing Handbook

6.16 CHAPTER SIX

FIGURE 6.14 Bellow expansion-joint detailing.

joint, thereby protecting them from traffic wear. Additionally, the bellows is closed,
which prevents accumulation of debris and water and, therefore, does not require a
cover plate for protection.
These systems do not allow for major irregularities in joint width. This would prevent
materials from performing in expansion or contraction modes. They also cannot take up
irregularities in substrate unlevelness. This requires that a joint be saw-cut to uniform
width and leveled before installation if necessary.
After adhesive is applied and bellows installed, air is injected to expand the joint cross
section, similarly to blowing up a balloon. This pressure is maintained until the adhesive
is cured, at which time the pressure valves are removed and pressure holes sealed. This
joint functions under movement in stress and deflection.
Material is supplied in roll lengths usually sufficient for seamless application. Should
seaming be necessary, ends are vulcanized together with solvents.
Bellows systems are effective for surface-mounted floor-to-wall building joints. It is not,
however, possible to turn the material 90° for changes in plane. Additionally, it is difficult
to terminate these systems, and manufacturers should be consulted for recommendations.
For remedial installations, any existing joint material must be removed completely and
interior joint sides must be cleaned for adhesive bonding. If existing joints are irregular in
width or shape, they should be cut to uniform size for proper installations. (See Table 6.6.)

TABLE 6.6 Bellow Expansion Joint Properties
Advantages Disadvantages
No cover plates required Maximum 3-inch width
Factory-manufactured Difficult to terminate
No debris or water collection Nonconforming to irregularities