[MassHistPres] experience with Azek?

[Ward Hamilton at Olde Mohawk Historic Preservation]

In the limited instances where wood-meets-earth, or water (window sills),
composites may appear to be an attractive alternative, but should be
considered with caution.  The new stair riser or fascia plate will not
show signs of degradation but it will conceal what's happening to wooden
structural members behind them.  So, when it fails, be prepared for
wholesale failure of the system.  ("Gee, the stairs looked great ... who
knew the stringers were rotted?")

PVC composites, like AZEK, are an attempt to cut corners and remove
maintenance and upkeep from the equation.  Consider recommending the use
of Spanish cedar, teak, poplar, oak, and other hardwoods in these limited
applications.  You may be surprised how close the price is to the
composite materials.

Like many issues confronting HDCs, this one can be attributed to a lack of
informed sources.  The building owner is making application and typically
knows only as much as the contractor has told them.  AZEK is widely
available and spends a tremendous amount of money "educating" would-be
consumers through marketing.

Consider the Secretary of the Interior's position on the subject:

"If repair by stabilization, consolidation, and conservation proves
inadequate, the next level of intervention involves the limited
replacement in kind of extensively deteriorated or missing parts of
features when there are surviving prototypes (for example, brackets,
dentils, steps, plaster, or portions of slate or tile roofing). The
replacement material needs to match the old both physically and visually,
i.e., wood with wood, etc. Thus, with the exception of hidden structural
reinforcement and new mechanical system components, substitute materials
are not appropriate in the treatment Preservation."    Standards for
Preservation and Guidelines for Preserving Historic Buildings
(http://www.cr.nps.gov/hps/tps/standguide/preserve/preserve_approach.htm)


Ward Hamilton

OLDE MOHAWK HISTORIC PRESERVATION INC
877.622.8973 online at OldeMohawk.com
Slate Roofing | Masonry | Restoration