Agenda - 10-05-2010 - 4g - Laserfiche WebLink

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�5 . 1 when applying Green Building standards designed for new construction to existing 2 buildings, particularly those constructed before World War II. It is important to 3 understand how older buildings were designed to work, particularly how they were q meant to "breathe" before installing retrofits that will make them air-tight. Some 5 solutions may save utility costs in the short term, only to create moisture problems 6 that can cause serious structural problems in the long term. Property owners 7 should seek the guidance of the HPC and SHPO to determine which technologies s provide the best energy solutions for their building, and to balance the cost of the 9 installment versus the anticipated payback period. 10 i i One of most common causes of building deterioration is moisture. Efforts to 12 encapsulate older buildings to keep their interiors at a certain temperature and 13 humidity level can, if not done properly, trap moisture. Such moisture problems ia are often hidden and hard to detect until the problem becomes substantial. The 15 application of synthetic siding over wood siding, in particular, often traps moisture 16 within exterior walls leading to structural damage. Installing insulation in exterior 17 walls can likewise trap moisture causing damage. 18 i9 Window replacement is perhaps the most controversial change to historic 2o buildings. New windows are expensive. The typical energy payback depends on 21 the cost and quality of the window, but expect at least ten years and in some 22 cases fifteen to twenty years. In addition, new windows, particularly vinyl 23 windows, can be difficult to repair and tend to last about ten to fifteen years before 24 needing replacement. 25 26 New windows are irreversible and change the appearance of a building. In 27 addition, the installation of new windows may eliminate a building's eligibility for 2s historic designation programs such as the National Register of Historic Places 29 and the Local Landmark Program, and the associated benefits of those programs. 3o In general, any improvement advertised as "maintenance free" should be avoided. 31 Recommended procedures to maintain and increase the energy efficiency of local 32 landmark buildings through traditional methods include: 33 ■ Reglaze sash and recaulk joinery as needed to ensure door and window units 34 are weather tight to resist wind and water. 3s ■ Insulate attics and basements or crawl spaces, if possible, to improve 36 efficiency of existing mechanical systems. 37 ■ Apply weather stripping to windows and doors. 3g ■ Retain natural site features, including shade trees, windbreaks, and other 39 vegetation, that moderate climatic factors for the local landmark property. 40 ■ Utilize operable windows, shutters, and louvered blinds to control ventilation. 41 42 43 DESIGN GUIDELINES for Utilities and Energy Retrofit 44 45 III-E-1. Retain and preserve traditional or inherent energy-conserving features of the 46 historic buildings such as porches, screen doors, etc. 47 as III-E-2. Install narrow profile exterior or interior storm windows that do not damage or 49 obscure existing sash and window frames for energy efficiency. Choose storm so windows that are painted or finished with a color compatible with the existing sash 51 color. If covering double-hung windows, select operable storm windows with 52 dividers that align with existing sash division. 53 9/28/2010 Draft Orange County Design Standards 37