uckpointing information

huangyhg

tuckpointing information
i am looking for information regarding the methods and materials used in tuckpointing.  i have found some at the pca in their "trowel tips".  but, what i am looking for is a specification to be used for the work in the field that would outline the depth of cut, cleaning of the joints, mortar mix, mortar additives and clean up.  thanks in advance for any help!
i'd look in astm's and army corps of engrs. manuals.
tuckpointing, originally, was a means of using a 'high quality' weatherproof mortar, for the outer 1/2" - 1" of the mortar joint and to provide a medium that could be tooled in a decorative fashion or to provide a finer finished work.  it allowed the 'master' or the skilled 'journeyman' the opportunity to do this work at their leisure.  in later times, it has become synonymous with repairing existing masonry mortar joints.
i'm not aware of any 'fast' rules about the amount of material to be removed.  i generally specify that all loose or unsuitable mortar should be replaced and, to maintain a 'visual continuity', usually stipulate that a minimum of 1/2" be replaced.  otherwise the repair can look 'spotchy'.
it's important to match the mortar to the work being undertaken.
in general, tuckpointing for remediation is done using the following procedure:
1. using tuckpoint grinder, remove outer 1/2-inch of mortar depth (depth may be increased to account for desired finish, to improve strength, or replace bad mortar.
2.  clean all joints with water and allow to dry.
3.  using a polymer modified mortar, re-point the mortar and finish as desired.
the canadian standard csa a371 has some excellent information regarding repointing masonry.  i agree in general with the points raised above; however, i generally specify that if a joint needs to be re-pointed (cracked, eroded or displaced mortar) a minimum of one inch should be removed or  to the depth required to obtain sound substrate.  in addition, caution is required on the type of mortar used to repair the joints.  use of too hard a mortar or implementing polymer may do more harm than good.  too much cement increases shrinkage, creates edge loading and aggravates water penetration. the mortar should always be softer than the masonry.  i generally use a weaker type n mortar or even type o for re-pointing.
jw
hi,