Abstract
Confronting a problem in retrofitting for improved roof system thermal efficiency, the roof designer must step back and consider many other factors. Retrofit poses a much tougher problem than new construction, for you must either live with or bear the cost of rectifying unfavorable conditions that can be totally avoided with a new roof design. The retrofit starts with an investigative analysis of the following: nature and conditions of existing roof system components; roof system history; roof system environment (interior RH, exterior surface contaminants, structural loads, vibration and other unusual considerations); new performance criteria (improved thermal performance generally requires reduced U factor, but condensation and the insulation's location - i.e., above or below the deck, etc. - also requires consideration); improved drainage (many existing roofs pond water, and the retrofit must correct this problem to justify the owner's capital investment.) As the first decision after assembling the foregoing information, the roof designer must choose between a retrofit and total tearoff replacement. As its major advantage, tearoff replacement offers an opportunity to inspect and repair the deck substrate prior to reroofing. Its major disadvantages include the major disruption of building operations and generally higher cost. Since tearoff replacement is essentially a new system, it lies outside the scope of this paper and hence will receive no further discussion.
Confronting a problem in retrofitting for improved roof system thermal efficiency, the roof designer must step back and consider many other factors. Retrofit poses a much tougher problem than new construction, for you must either live with or bear the cost of rectifying unfavorable conditions that can be totally avoided with a new roof design. The retrofit starts with an investigative analysis of the following: nature and conditions of existing roof system components; roof system history; roof system environment (interior RH, exterior surface contaminants, structural loads, vibration and other unusual considerations); new performance criteria (improved thermal performance generally requires reduced U factor, but condensation and the insulation's location - i.e., above or below the deck, etc. - also requires consideration); improved drainage (many existing roofs pond water, and the retrofit must correct this problem to justify the owner's capital investment.) As the first decision after assembling the foregoing information, the roof designer must choose between a retrofit and total tearoff replacement. As its major advantage, tearoff replacement offers an opportunity to inspect and repair the deck substrate prior to reroofing. Its major disadvantages include the major disruption of building operations and generally higher cost. Since tearoff replacement is essentially a new system, it lies outside the scope of this paper and hence will receive no further discussion.
Date
0/1979
0/1979
Author(s)
Richard Fricklas
Richard Fricklas
Page(s)
30-43
30-43
Keyword(s)
retrofit; roof history; exterior contaminant; structural loads; RH; vibration; roof environment; performance criteria
retrofit; roof history; exterior contaminant; structural loads; RH; vibration; roof environment; performance criteria