Page 359 - Construction Waterproofing Handbook

REMEDIAL WATERPROOFING 8.19
Bag grouting refers to a technique using burlap bags to remove grout after application to
wall areas. Grout is used to fill pores, cracks, and fissures in both the joints and masonry,
waterproofing an entire wall facade. Face grouting does not change the color or aesthetics
of wall surfaces nor the breathability of facing materials. Face grouting will, however,
impart a uniform color or shading to walls; the effects depend on the grout color chosen.
Testing of sample areas should be completed to analyze application effectiveness and
acceptability of the finished appearance.
Grouting is a highly labor-intensive system, and the mechanics doing it should be
trained and experienced in system application. Should grout be brushed off too quickly,
material will be removed from masonry pores and will not sufficiently waterproof. If grout
is allowed to cure completely, it will be virtually impossible to remove, and the entire sub-
strate aesthetics will be changed.
Application timing and removal varies greatly, and is affected by weather (dry, humid,
sunny, or overcast), substrate conditions (smooth, glazed, or porous), and material compo-
sition. Mechanics must be experienced to know when the removal process should begin,
as this may change daily depending on specific project conditions, including weather
(Table 8.6).

FACE GROUTING APPLICATION

Masonry walls should be cleaned completely to ensure that grout will bond to both exist-
ing masonry and mortar. All contaminants, including previously applied sealants, must be
removed. Walls should be checked for residue of previous waterproof coatings or sealer
applications that hinder out-bonding. All seriously deteriorated mortar joints should be
tuck-pointed before grout application.
Grout materials are supplied in dry mix form with acrylic or integral bonding agents. Dry
bag mix products are mixed with clean water in specified portions for existing conditions.
Grout should be brushed and scrubbed in circular motions to an entire wall area. The
wall surface must be kept continually and uniformly damp to prevent grout from drying
before removal. Grout should be applied uniformly and completely, to fill all voids, pores,
and cracks (Fig. 8.15).
At the proper time, determined by job conditions, removal should begin. Grout is
removed using stiff bristle brushes, burlap bags, or other effective methods. Proper
removal will leave masonry free of grout deposits with no change in color or streaking.
No priming is required, although surfaces should be kept properly damp. Materials
should not be applied to unsound or defective substrates or joints. Temperature must be
above freezing during application.

TABLE 8.6 Face Grouting Properties
Advantages Disadvantages
Repairs both masonry and joints Cost
Environmentally safe Labor-intensive
Low water absorption after installation Difficult installation