A04_SOW.pdf

Windows Preserve Architecture Features

Fort Larned National Historic Site

Project Manual

Dated February 14, 2019

National Park Service

Midwest Region

MWRO Major Acquisition Buying Office

Purpose

Fort Larned National Historic Site is seeking proposals for work on Eleven Six over Six and Four Three over Six double hung wood windows; to remove lead paint from windows friction points and encapsulate remaining areas of the window frame; repair wood elements of window frames and sills in accordance with treatment description of Preservation Brief #09; remove and replace parting bead and stops reproducing the profile and dimension of existing; repair wood element of the window sashes; bed and glaze glass panes and apply three coats of finish paint.

Work is to be performed on the park’s Commanding Officers Quarters.

Introduction

Fort Larned was established in 1859 as a base of military operations to protect U.S. Mail traffic along the Santa Fe Trail; It also served as an assemble point for Hancock Expedition; and as Issuing station of treaty annuities for the Central Plains Indians by the Bureau of Indian Affairs under the terms of the Fort Wise Treaty of 1861. With nine restored buildings, it survives as one of the best examples of Indian Wars period forts. Most of the buildings including: barracks, commissary, officer’s quarters and more, are furnished to their original appearance.

Deliverable / Location Fort Larned NHS 1767 Kansas Highway 156 Larned Kansas 67550 Commanding Officer Quarters The Fort’s Maintenance Complex is located @ 1335 180th avenue.

The Fort is located six miles west of Larned on Kansas highway 156 and Five miles east of the intersection of US highway 183 and Kansas highway 156.

Scope of Work and Specification

General Condition

Contractor is responsible to field verify any and all measurements and information needed to complete this contract. All work is from exterior envelop to interior side of interior stop component of the window.

This contract is fund specific, no additional funds are available. If unexpected work or condition arises in the execution of this contract which incurred additional cost, the original scope of work may be reduced to offset the additional cost. The government will not incur additional expense for this agreement.

• Contractor use of the premises will be limited to designated area near the structure and during operational hours only. Monday thru Friday 7:30AM to 4:30PM.

• Contractor is to keep work site clean, removing debris on a daily basis.

• Staging area Contractor is to confine storage of material or equipment to area designated by the Contracting Officer Technical Representative (COTR). Contractor is to provide security for Contractors property; government will not assume this liability.

• Contractor will be limited to one vehicle with in the designated Fort area, all other vehicles must be parked in the visitor parking area. Additional restrictions may be imposed by the Superintendent. A special permit will not relieve Contractor of liability for damage which may result from vehicles and trailer use. Hauling Restrictions:

Contractor shall comply with all legal load restrictions for vehicles and trailers.

• Contractors will limit unnecessary noise, no radios, yelling and or swearing. Contractor is to ensure that employees do note wear article of clothing have vulgar statements or symbols.

• Contractor is to establish a smoking area for employees 25’ from the structure and post a fire extinguisher at smoking area.

• NO SMOKING IN BUILDINGS!

• No unattended heat source is permitted, all heat sources must be extinguished 2 hours prior to end of day and fire watch posted.

• Contractor must report all accidents which occur during the execution of this work.

Contractor is to comply with all applicable OSHA standards. The Park will be open to the public during this agreement. Contractor is to secure any hazardous area created during this agreement to prevent harm to visitors. Contractor is to maintain access of work area for National Park Service official business throughout the project.

• All exterior painting shall be completed in compliance with the Kansas Lead-Based Paint Renovation, Repair and Painting Rules.

SCHEDULES and SUBMITTALS:

• Period of Performance is 120 day after Notice to Proceed is issued.

• Contractor shall submit a digital copy of Progress Schedule, and a Schedule of Values 10 day after receiving the Notice to Proceed and before beginning work. The CO, Contract Specialist, and COR will review the Progress Schedule and the Schedule of Values for content. Progress Schedule shall have estimated start and completion dates for each phase of the project.

• Warranties and Guarantees: All workmanship shall be warranted free from defects in workmanship for a period of five (5) years from the date of the Letter of Acceptance. All products shall carry in effect, the manufacturer’s commercial limited product warranty.

The Contractor shall be responsible for correction of any deficiencies or failures which may result from normal usage at no cost to the Government during warranty period.

• Submit Shop drawing of repair work performed on each window.

Materials/Submittals

Contractor is to provide all materials needed to complete described work. All wood material is too be harvested from sustainable forest. Wood is to be clear or varnish quality. Wood material is to be of the same species as existing windows components.

• Submit 1liner foot or 1square foot samples of wood material with profile detailed as needed for comparison.

• Submit 1liner foot samples of brass weather stripping.

• Submit 1 paper copy and 1 electronic version Safety Data Sheet (SDS) of Paint, Cleaner, Paint Remover, Glazing or other product used in the performance of this contract.

WORK PERFORMANCE

Barriers Signage

• Construct barrier that clearly identify work area

• Post signage with appropriate warring or notice information for ongoing work activities;

and that identifies potential hazardous condition

Selective Demolition:

Contractor to field verify all dimension

• Construct temporary tenting for Lead Paint removal at friction points

• Remove lead paint in accordance with Kansas Regulation

• It is permitted to remove mortar along the area next to window jambs and sill to conduct needed repairs. Contractor will coordinate with NPS for mortar to repoint affected areas.

• Stones dislodged in this demolition process must be retained for use when installing new mortar.

• Remove window sashes for repair and or replacement. Sashes can be taking off site to a shop to perform repairs. Contract is to provide inventory of such item prior to removal for government property. If off site shop is use; shop must be accessible for inspection of work progress by the government.

• Removal and disposal of parting bead and interior stop is permitted

• When removing glazing from sash proceeds with caution to retain the glass for use in final assemble.

• Remove deteriorated wood features with sensitivity; retaining as much of the non-deteriorated material as possible. Reference NPS Preservation Brief that are attached to scope; these publication are the guidance this scope is based upon.

Construction/Installation

Contractor to field verify all dimension

Install windows sash so they are operational top sash is to be affixed by the installation of stop blocks; (Blocks to match those of similar window on other park structures).

Window Frames and Sashes

• Repair wood or stone pieces need to match existing in wood species, dimension and profiles

• Pieces are to be identified, permanently marked with the calendar year repairs are made.

This identification mark is to be place on non-finished surface.

• Replace parting bead and interior stop.

• Identify individual glass panes per the sash, and take appropriate precaution not to break glass in the removal process; they will be reused when sash repairs are complete.

Replacement glass is to be restoration reproduction such as provided by Bendheim Restoration Glass.

• Prime paint or linseed oil the sash glazing bed prior and let cure prior to install glass

• Bed glaze glass prior to setting in sash

• Glaze glass so that the glazing does not protrude past the bedding profile of the sash and install glazing point one inch from corner and four inch on center in field of glass.

• Allow glazing to cure prior to primer and finish paint

• Install brass weather strip at sashes meeting rail and lower sash. Kerf window sash as need to fit weather strip material. The Kerf cut shall not extend into either the top or lower sash meeting rails. Kerf cut is to limited to the dimension of the weather strip

• Install sashes so they are operational (see above note)

• Set and fill all fasteners holes and sand flush and smooth prior to painting

• Prime paint all bare wood and back prime any new wood elements

• Paint two coat with fine boar bristle brush

Suggested Material or Comparable

• Primer; Porter/ Pittsburgh Paint and Glass (PPG) bonding and encapsulating primer PPG 17921

• Paint: Porter/ Pittsburgh Paint and Glass (PPG) 631 Brilliant White

• Restoration Glass; Bendheim Restoration Glass

• Glazing Compound; Sarco Multi-Glaze

Attachment

Preservation Briefs #09 and #37

Kansas Lead-Based Paint Renovation, Repair and Painting Rule

U.S. Department of the Interior National Park Service Cultural Resources

Heritage Preservation Services

Preservation Briefs: 9 The Repair of Historic Wooden Windows

JohnH. ~yers------------------------------------------------------------------

The windows on many historic buildings are an important aspect of the architectural character of those buildings.

Their design, craftsmanship, or other qualities may make them worthy of preservation . This is self-evident for or namental windows, but it can be equally true for warehouses or factories where the windows may be the most dominant visual element of an otherwise plain building (see figure 1). Evaluating the significance of these windows and planning for their repair or replace ment can be a complex process involving both objective and subjective considerations . The Secretary of the In terior's Standards for Rehabilitation, and the accompany ing guidelines, call for respecting the significance of original materials and features , repairing and retaining them wherever possible, and when necessary, replacing them in kind. This Brief is based on the issues of significance and repair which are implicit in the standards, but the primary emphasis is on the technical issues of planning for the repair of windows including evaluation of their physical condition, techniques of repair, and design considerations when replacement is necessary.

Figure 1. Windows are frequently important visual focal points, especial lyon simple facades such as this mill building. Replacement of the multi pane windows here with larger panes could dramatically change the ap pearance of the building. The areas of missing windows convey the im pression of such a change. Photo: John T. Lowe

Much of the technical section presents repair techniques as an instructional guide for the do-it-yourselfer. The infor mation will be useful, however, for the architect, contrac tor, or developer on large-scale projects. It presents a methodology for approaching the evaluation and repair of existing windows, and considerations for replacement, from which the professional can develop alternatives and specify appropriate materials and procedures.

Architectural or Historical Significance Evaluating the architectural or historical significance of windows is the first step in planning for window treat ments, and a general understanding of the function and history of windows is vital to making a proper evalua tion. As a part of this evaluation, one must consider four basic window functions: admitting light to the interior spaces, providing fresh air and ventilation to the in terior, providing a visual link to the outside world, and enhancing the appearance of a building . No single factor can be disregarded when planning window treatments; for example, attempting to conserve energy by closing up or reducing the size of window openings may result in the use of more energy by increasing electric lighting loads and decreasing passive solar heat gains.

Historically, the first windows in early American houses were casement windows; that is, they were hinged at the side and opened outward. In the beginning of the eigh teenth century single- and double-hung windows were in troduced. Subsequently many styles of these vertical sliding sash windows have come to be associated with specific building periods or architectural styles, and this is an important consideration in determining the significance of windows, especially on a local or regional basis. Site specific, regionally oriented architectural comparisons should be made to determine the significance of windows in question. Although such comparisons may focus on specific window types and their details, the ultimate deter mination of significance should be made within the con text of the whole building, wherein the windows are one architectural element (see figure 2).

After all of the factors have been evaluated, windows should be considered significant to a building if they; 1) are original, 2) reflect the original design intent for the building, 3) reflect period or regional styles or building practices, 4) reflect changes to the building resulting from major periods or events, or 5) are examples of ex ceptional craftsmanship or design. Once this evaluation of significance has been completed, it is possible to pro-

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Muntin Profiles

These are only three examples of many possible profiles. Mun tins can contribute substantially to window significance.

Figure 2. These drawings of window details identify major components, terminology, and installation details for a wooden double-hung window.

ceed with planning appropriate treatments, beginning with an investigation of the physical condition of the windows.

Physical Evaluation

The key to successful planning for window treatments is a careful evaluation of existing physical conditions on a unit-by-unit basis. A graphic or photographic system may be devised to record existing conditions and illustrate the scope of any necessary repairs. Another effective tool is a window schedule which lists all of the parts of each win dow unit. Spaces by each part allow notes on existing conditions and repair instructions. When such a schedule is completed, it indicates the precise tasks to be performed in the repair of each unit and becomes a part of the specifications. In any evaluation, one should note at a minimum, 1) window location, 2) condition of the paint,

3) condition of the frame and sill, 4) condition of the sash (rails, stiles and muntins), 5) glazing problems, 6) hard ware, and 7) the overall condition of the window (ex cellent, fair, poor, and so forth).

Many factors such as poor design, moisture, vandalism, insect attack, and lack of maintenance can contribute to window deterioration, but moisture is the primary con tributing factor in wooden window decay. All window units should be inspected to see if water is entering around the edges of the frame and, if so, the joints or seams should be caulked to eliminate this danger. The glazing putty should be checked for cracked, loose, or missing sections which allow water to saturate the wood, especial ly at the joints. The back putty on the interior side of the pane should also be inspected, because it creates a seal which prevents condensation from running down into the joinery. The sill should be examined to insure that it slopes downward away from the building and Cl-llows water to drain off. In addition, it may be advisable to cut a dripline along the underside of the sill. This almost in visible treatment will insure proper water run-off, particu-larly if the bottom of the sill is flat. Any conditions, in cluding poor original design, which permit water to come in contact with the wood or to puddle on the sill must be corrected as they contribute to deterioration of the win dow.

One clue to the location of areas of excessive moisture is the condition of the paint; therefore, each window should be examined for areas of paint failure. Since ex cessive moisture is detrimental to the paint bond, areas of paint blistering, cracking, flaking, and peeling usually identify points of water penetration, moisture saturation, and potential deterioration. Failure of the paint should not, however, be mistakenly interpreted as a sign that the wood is in poor condition and hence, irreparable. Wood is frequently in sound physical condition beneath unsight ly paint. After noting areas of paint failure, the next step is to inspect the condition of the wood, particularly at the points identified during the paint examination.

Each window should be examined for operational soundness beginning with the lower portions of the frame and sash. Exterior rainwater and interior condensation can flow downward along the window, entering and collecting at points where the flow is blocked. The sill, joints be tween the sill and jamb, corners of the bottom rails and muntin joints are typical points where water collects and deterioration begins (see figure 3). The operation of the window (continuous opening and closing over the years and seasonal temperature changes) weakens the joints, causing movement and slight separation. This process makes the joints more vulnerable to water which is readi ly absorbed into the end-grain of the wood. If severe deterioration exists in these areas, it will usually be ap parent on visual inspection, but other less severely deteri orated areas of the wood may be tested by two traditional methods using a small ice pick.

An ice pick or an awl may be used to test wood for soundness. The technique is simply to jab the pick into a wetted wood surface at an angle and pry up a small sec-

Figure 3. Deterioration of poorly maintained windows usually begins on horizontal surfaces and at joints where water can collect and saturate the wood. The problem areas are clearly indicated by paint failure due to moisture. Photo: Baird M. Smith, AlA tion of the wood. Sound wood will separate in long fibrous splinters, but decayed wood will lift up in short ir regular pieces due to the breakdown of fiber strength.

Another method of testing for soundness consists of pushing a sharp object into the wood, perpendicular to the surface. If deterioration has begun from the hidden side of a member and the core is badly decayed, the visi ble surface may appear to be sound wood. Pressure on the probe can force it through an apparently sound skin to penetrate deeply into decayed wood. This technique is especially useful for checking sills where visual access to the underside is restricted.

Following the inspection and analysis of the results, the scope of the necessary repairs will be evident and a plan for the rehabilitation can be formulated. Generally the ac tions necessary to return a window to "like new" condi tion will fall into three broad categories: 1) routine main tenance procedures, 2) structural stabilization, and 3) parts replacement. These categories will be discussed in the following sections and will be referred to respectively as Repair Class I, Repair Class II, and Repair Class III.

Each successive repair class represents an increasing level of difficulty, expense, and work time. Note that most of the points mentioned in Repair Class I are routine main tenance items and should be provided in a regular main tenance program for any building. The neglect of these routine items can contribute to many common window problems.

Before undertaking any of the repairs mentioned in the following sections all sources of moisture penetration should be identified and eliminated, and all existing decay fungi destroyed in order to arrest the deterioration pro cess. Many commercially available fungicides and wood preservatives are toxic, so it is extremely important to follow the manufacturer's recommendations for applica tion, and store all chemical materials away from children and animals. After fungicidal and preservative treatment the windows may be stabilized, retained, and restored with every expectation for a long service life.

Repair Class I: Routine Maintenance

Repairs to wooden windows are usually labor intensive and relatively uncomplicated. On small scale projects this allows the do-it-yourselfer to save money by repairing all or part of the windows. On larger projects it presents the opportunity for time and money which might other wise be spent on the removal and replacement of existing windows, to be spent on repairs, subsequently saving all or part of the material cost of new window units. Regard less of the actual costs, or who performs the work, the evaluation process described earlier will provide the knowledge from which to specify an appropriate work program, establish the work element priorities, and iden tify the level of skill needed by the labor force.

The routine maintenance required to upgrade a window to "like new" condition normally includes the following steps: 1) some degree of interior and exterior paint removal, 2) removal and repair of sash (inCluding reglaz ing where necessary) , 3) repairs to the frame, 4) weather stripping and reinstallation of the sash, and 5) repainting.

These operations are illustrated for a typical double-hung wooden window (see figures 4a-f) , but they may be adapted to other window types and styles as applicable.

Historic windows have usually acquired many layers of paint over time. Removal of excess layers or peeling and flaking paint will facilitate operation of the window and restore the clarity of the original detailing. Some degree of paint removal is also necessary as a first step in the prop er surface preparation for subsequent refinishing (if paint color analysis is desired, it should be conducted prior to the onset of the paint removal). There are several safe and effective techniques for removing paint from wood, depending on the amount of paint to be removed . Several techniques such as scraping, chemical stripping, and the use of a hot air gun are discussed in "Preservation Briefs:

10 Paint Removal from Historic Woodwork" (see Addi tional Reading section at end) .

Paint removal should begin on the interior frames , be ing careful to remove the paint from the interior stop and the parting bead, particularly along the seam where these stops meet the jamb. This can be accomplished by run ning a utility knife along the length of the seam, breaking the paint bond. It will then be much easier to remove the stop, the parting bead and the sash. The interior stop may be initially loosened from the sash side to avoid visible scarring of the wood and then gradually pried loose using a pair of putty knives, working up and down the stop in small increments (see figure 4b) . With the stop removed, the lower or interior sash may be withdrawn . The sash cords should be detached from the sides of the sash and their ends may be pinned with a nail or tied in a knot to prevent them from falling into the weight pocket.

Removal of the upper sash on double-hung units is similar but the parting bead which holds it in place is set into a groove in the center of the stile and is thinner and more delicate than the interior stop. After removing any paint along the seam, the parting bead should be carefully pried out and worked free in the same manner as the in terior stop. The upper sash can be removed in the same manner as the lower one and both sash taken to a conve nient work area (in order to remove the sash the interior stop and parting bead need only be removed from one side of the window). Window openings can be covered with polyethylene sheets or plywood sheathing while the sash are out for repair.

The sash can be stripped of paint using appropriate techniques, but if any heat treatment is used (see figure 4c), the glass should be removed or protected from the sudden temperature change which can cause breakage . An

Figure 4a. The following series of photographs of the repair of a historic double-hung window use a unit which is structurally sound but has many layers of paint, some cracked and missing putty, slight separation at the joints, broken sash cords, and one cracked pane. Photo: John H. Myers

Figure 4d. Reglazing or replacement of the putty requires that the existing putty be removed manually, the glazing points be extracted, the glass removed, and the back putty scraped out. To reglaze, a bed of putty is laid around the perimeter of the rabbet, the pane is pressed into place, glazing points are inserted to hold the pane (shown), and a final seal of putty is beveled around the edge of the glass. Photo: John H.

Myers

Figure 4b. After removing paint from the seam between the interior stop and the jamb, the stop can be pried out and gradually worked loose using a pair of putty knives as shown. To avoid visible scarring of the wood, the sash can be raised and the stop pried loose initially from the outer side.

Photo: John H. Myers

Figure 4e. A common repair is the replacement of broken sash cords with new cords (shown) or with chains. The weight pocket is often accessible through a removable plate in the jamb, or by removing the interior trim. Photo: John H. Myers

Figure 4c. Sash can be removed and repaired in a convenient work area. Paint is being removed from this sash with a hot air gun while an asbestos sheet protects the glass from sudden temperature change. Photo: John H. Myers

( ( 1 Figure 4£. Following the relatively simple repairs, the window is weathertight, like new in appearance, and serviceable for many years to come. Both the historic material and the detailing and craftsmanship of this original window have been preserved. Photo: John H. Myers overlay of aluminum foil on gypsum board or asbestos can protect the glass from such rapid temperature change. It is important to protect the glass because it may be historic and often adds character to the window.

Deteriorated putty should be removed manually, taking care not to damage the wood along the rabbet . If the glass is to be removed, the glazing points which hold the glass in place can be extracted and the panes numbered and removed for cleaning and reuse in the same open ings. With the glass panes out, the remaining putty can be removed and the sash can be sanded, patched, and primed with a preservative primer. Hardened putty in the rabbets may be softened by heating with a soldering iron at the point of removal. Putty remaining on the glass may be softened by soaking the panes in linseed oil, and then removed with less risk of breaking the glass. Before reinstalling the glass, a bead of glazing compound or linseed oil putty should be laid around the rabbet to cushion and seal the glass. Glazing compound should only be used on wood which has been brushed with linseed oil and primed with an oil based primer or paint. The pane is then pressed into place and the glaz ing points are pushed into the wood around the perim eter of the pane (see figure 4d) . The final glazing com pound or putty is applied and beveled to complete the seal. The sash can be refinished as desired on the inside and painted on the outside as soon as a "skin" has formed on the putty, usually in 2 or 3 days. Exterior paint should cover the beveled glazing compound or putty and lap over onto the glass slightly to complete a weathertight seal. After the proper curing times have elapsed for paint and putty, the sash will be ready for reinstallation.

While the sash are out of the frame, the condition of the wood in the jamb and sill can be evaluated. Repair and refinishing of the frame may proceed concurrently with repairs to the sash, taking advantage of the curing times for the paints and putty used on the sash. One of the most common work items is the replacement of the sash cords with new rope cords or with chains (see figure 4e). The weight pocket is frequently accessible through a door on the face of the frame near the sill , but if no door exists, the trim on the interior face may be removed for access . Sash weights may be increased for easier window operation by elderly or handicapped persons . Additional repairs to the frame and sash may include consolidation or replacement of deteriorated wood. Techniques for these repairs are discussed in the following sections.

The operations just discussed summarize the efforts necessary to restore a window with minor deterioration to "like new" condition (see figure 4f) . The techniques can be applied by an unskilled person with minimal training and experience. To demonstrate the practicality of this ap proach, and photograph it, a Technical Preservation Ser vices staff member repaired a wooden double-hung, two over two window which had been in service over ninety years. The wood was structurally sound but the window had one broken pane, many layers of paint , broken sash cords and inadequate, worn-out weatherstripping. The staff member found that the frame could be stripped of paint and the sash removed quite easily . Paint , putty and glass removal required about one hour for each sash, and the reglazing of both sash was accomplished in about one hour. Weatherstripping of the sash and frame , replace ment of the sash cords and reinstallation of the sash, part ing bead, and stop required an hour and a half. These times refer only to individual operations; the entire proc-ess took several days due to the drying and curing times for putty, primer, and paint, however, work on other win dow units could have been in progress during these lag times.

Repair Class II: Stabilization The preceding description of a window repair job focused on a unit which was operationally sound. Many windows will show some additional degree of physical deteriora tion, especially in the vulnerable areas mentioned earlier, but even badly damaged windows can be repaired using simple processes. Partially decayed wood can be water proofed, patched, built-up, or consolidated and then painted to achieve a sound condition, good appearance, and greatly extended life. Three techniques for repairing partially decayed or weathered wood are discussed in this section, and all three can be accomplished using products available at most hardware stores.

One established technique for repairing wood which is split, checked or shows signs of rot, is to: 1) dry the wood, 2) treat decayed areas with a fungicide, 3) water proof with two or three applications of boiled linseed oil (applications every 24 hours), 4) fill cracks and holes with putty, and 5) after a "skin" forms on the putty, paint the surface. Care should be taken with the use of fungicide which is toxic. Follow the manufacturers' directions and use only on areas which will be painted. When using any technique of building up or patching a flat surface, the finished surface should be sloped slightly to carry water away from the window and not allow it to puddle. Caulk ing of the joints between the sill and the jamb will help reduce further water penetration.

When sills or other members exhibit surface weathering they may also be built-up using wood putties or home made mixtures such as sawdust and resorcinol glue, or whiting and varnish. These mixtures can be built up in successive layers, then sanded, primed, and painted. The same caution about proper slope for flat surfaces applies to this technique.

Wood may also be strengthened and stabilized by con solidation, using semi-rigid epoxies which saturate the porous decayed wood and then harden. The surface of the consolidated wood can then be filled with a semi-rigid epoxy patching compound, sanded and painted (see figure 5). Epoxy patching compounds can be used to build up

Figure 5. This illustrates a two-part epoxy patching compound used to fill the surface of a weathered sill and rebuild the missing edge. When the epoxy cures, it can be sanded smooth and painted to achieve a durable and waterproof repair. Photo: John H. Myers missing sections or decayed ends of members. Profiles can be duplicated using hand molds, which are created by pressing a ball of patching compound over a sound sec tion of the profile which has been rubbed with butcher's wax. This can be a very efficient technique where there are many typical repairs to be done. Technical Preserva tion Services has published Epoxies for Wood Repairs in Historic Buildings (see Additional Reading section at end), which discusses the theory and techniques of epoxy repairs. The process has been widely used and proven in marine applications; and proprietary products are avail able at hardware and marine supply stores. Although epoxy materials may be comparatively expensive, they hold the promise of being among the most durable and long lasting materials available for wood repair.

Any of the three techniques discussed can stabilize and restore the appearance of the window unit. There are times, however, when the degree of deterioration is so ad vanced that stabilization is impractical, and the only way to retain some of the original fabric is to replace damaged parts.

Repair Class III: Splices and Parts Replacement When parts of the frame or sash are so badly deteriorated that they cannot be stabilized there are methods which permit the retention of some of the existing or original fabric. These methods involve replacing the deteriorated parts with new matching pieces, or splicing new wood in to existing members. The techniques require more skill and are more expensive than any of the previously dis cussed alternatives. It is necessary to remove the sash and / or the affected parts of the frame and have a carpenter or woodworking mill reproduce the damaged or missing parts. Most millwork firms can duplicate parts, such as muntins, bottom rails, or sills , which can then be incorporated into the existing window, but it may be necessary to shop around because there are several factors controlling the practicality of this approach. Some wood working mills do not like to repair old sash because nails or other foreign objects in the sash can damage expensive knives (which cost far more than their profits on small repair jobs); others do not have cutting knives to duplicate muntin profiles. Some firms prefer to concen trate on larger jobs with more profit potential, and some may not have a craftsman who can duplicate the parts. A little searching should locate a firm which will do the job, and at a reasonable price. If such a firm does not exist locally, there are firms which undertake this kind of repair and ship nationwide. It is possible, however, for the advanced do-it-yourselfer or craftsman with a table saw to duplicate moulding profiles using techniques discussed by Gordie Whittington in "Simplified Methods for Reproducing Wood Mouldings," Bulletin of the Association for Preservation Technology, Vol. III, No . 4, 1971, or illustrated more recently in The Old House, Time-Life Books, Alexandria, Virginia, 1979.

The repairs discussed in this section involve window frames which may be in very deteriorated condition, possibly requiring removal; therefore, caution is in order. The actual construction of wooden window frames and sash is not complicated. Pegged mortise and tenon units can be disassembled easily, if the units are out of the building. The installation or connection of some frames to the surrounding structure, especially masonry walls, can complicate the work immeasurably, and may even require dismantling of the wall. It may be useful , therefore, to take the following approach to frame repair: 1) conduct regular maintenance of sound frames to achieve the longest life possible, 2) make necessary repairs in place wherever possible, using stabilization and splicing tech niques, and 3) if removal is necessary, thoroughly in vestigate the structural detailing and seek appropriate pro fessional consultation.

Another alternative may be considered if parts replace ment is required, and that is sash replacement. If extensive replacement of parts is necessary and the job becomes prohibitively expensive it may be more practical to pur chase new sash which can be installed into the existing frames . Such sash are available as exact custom reproduc tions, reasonable facsimiles (custom windows with similar profiles), and contemporary wooden sash which are similar in appearance . There are companies which still manufacture high quality wooden sash which would duplicate most historic sash. A few calls to local build-ing suppliers may provide a source of appropriate replace ment sash, but if not, check with local historical associations, the state historic preservation office, or preservation related magazines and supply catalogs for information.

If a rehabilitation project has a large number of win dows such as a commercial building or an industrial com plex, there may be less of a problem arriving at a solu tion . Once the evaluation of the windows is completed and the scope of the work is known, there may be a potential economy of scale. Woodworking mills may be interested in the work from a large project; new sash in volume may be considerably less expensive per unit ;

crews can be assembled and trained on site to perform all of the window repairs; and a few extensive repairs can be absorbed (without undue burden) into the total budget for a large number of sound windows. While it may be expensive for the average historic home owner to pay seventy dollars or more for a mill to grind a custom knife to duplicate four or five bad muntins, that cost becomes negligible on large commercial projects which may have several hundred windows.

Most windows should not require the extensive repairs discussed in this section . The ones which do are usually in buildings which have been abandoned for long periods or have totally lacked maintenance for years. It is necessary to thoroughly investigate the alternatives for windows which do require extensive repairs to arrive at a solution which retains historic significance and is also economically feasible . Even for projects requiring repairs identified in this section, if the percentage of parts replacement per window is low, or the number of windows requiring repair is small, repair can still be a cost effective solution.

Weatherization A window which is repaired should be made as energy ef ficient as possible by the use of appropriate weather stripping to reduce air infiltration. A wide variety of products are available to assist in this task . Felt may be fastened to the top, bottom, and meeting rails, but may have the disadvantage of absorbing and holding moisture, particularly at the bottom rail. Rolled vinyl strips may also be tacked into place in appropriate locations to reduce infiltration. Metal strips or new plastic spring strips may be used on the rails and, if space permits, in the channels between the sash and jamb. Weatherstripping is a historic treatment, but old weatherstripping (felt) is not likely to perform very satisfactorily. Appropriate con temporary weatherstripping should be considered an in tegral part of the repair process for windows. The use of sash locks installed on the meeting rail will insure that the sash are kept tightly closed so that the weatherstripping will function more effectively to reduce infiltration.

Although such locks will not always be historically accu rate, they will usually be viewed as an acceptable contem porary modification in the interest of improved thermal performance.

Many styles of storm windows are available to improve the thermal performance of existing windows. The use of exterior storm windows should be investigated whenever feasible because they are thermally efficient, cost-effective, reversible, and allow the retention of original windows (see "Preservation Briefs: 3") . Storm window frames may be made of wood, aluminum, vinyl, or plastic; however, the use of unfinished aluminum storms should be avoided. The visual impact of storms may be minimized by selecting colors which match existing trim color.

Arched top storms are available for windows with special shapes. Although interior storm windows appear to offer an attractive option for achieving double glazing with minimal visual impact, the potential for damaging con densation problems must be addressed. Moisture which becomes trapped between the layers of glazing can con dense on the colder, outer prime window, potentially leading to deterioration. The correct approach to using in terior storms is to create a seal on the interior storm while allowing some ventilation around the prime window. In actual practice, the creation of such a durable, airtight seal is difficult.

Window Replacement Although the retention of original or existing windows is always desirable and this Brief is intended to encourage that goal, there is a point when the condition of a win dow may clearly indicate replacement. The decision proc ess for selecting replacement windows should not begin with a survey of contemporary window products which are available as replacements, but should begin with a look at the windows which are being replaced. Attempt to understand the contribution of the window(s) to the ap pearance of the facade including: 1) the pattern of the openings and their size; 2) proportions of the frame and sash; 3) configuration of window panes; 4) muntin pro files; 5) type of wood; 6) paint color; 7) characteristics of the glass; and 8) associated details such as arched tops, hoods, or other decorative elements. Develop an under standing of how the window reflects the period, style, or regional characteristics of the building, or represents tech nological development.

Armed with an awareness of the significance of the ex isting window, begin to search for a replacement which retains as much of the character of the historic window as possible. There are many sources of suitable new win dows. Continue looking until an acceptable replacement can be found. Check building supply firms, local wood working mills, carpenters, preservation oriented maga zines, or catalogs or sUl'pliers of old building materials, for product information. Local historical associations and state historic preservation offices may be good sources of information on products which have been used success fully in preservation projects.

Consider energy efficiency as one of the factors for replacements, but do not let it dominate the issue. Energy conservation is no excuse for the wholesale destruction of historic windows which can be made thermally efficient by historically and aesthetically acceptable means. In fact , a historic wooden window with a high quality storm win dow added should thermally outperform a new double glazed metal window which does not have thermal breaks (insulation between the inner and outer frames in tended to break the path of heat flow) . This occurs because the wood has far better insulating value than the metal, and in addition many historic windows have high ratios of wood to glass, thus reducing the area of highest heat transfer. One measure of heat transfer is the U-value, the number of Btu's per hour transferred through a square foot of material. When comparing thermal performance, the lower the U-value the better the performance. Accord ing to ASHRAf 1977 Fundamentals, the U-values for single glazed wooden windows range from 0.88 to 0.99.

The addition of a storm window should reduce these figures to a range of 0.44 to 0.49. A non-thermal break, double-glazed metal window has a U-value of about 0.6.

Conclusion Technical Preservation Services recommends the retention and repair of original windows whenever possible. We believe that the repair and weatherization of existing wooden windows is more practical than most people realize, and that many windows are unfortunately re placed because of a lack of awareness of techniques for evaluation, repair, and weatherization. Wooden windows which are repaired and properly maintained will have greatly extended service lives while contributing to the historic character of the building. Thus, an important ele ment of a building's significance will have been preserved for the future.

Additional Reading ASHRAE Handbook-1977 Fundamentals. New York: American Society of Heating, Refrigerating and Air-conditioning Engineers, 1978 (chapter 26).

Ferro, Maximillian. Preservation: Present Pathway to Fall River's Future.

Fall River, Massachusetts: City of Fall River, 1979 (chapter 7).

"Fixing Double-Hung Windows." Old House Journal (no. 12, 1979): 135.

Look, David W. "Preservation Briefs: 10 Paint Removal from Historic Woodwork." Washington, DC: Technical Preservation Services, U.S. Department of the Interior, forthcoming.

Morrison, Hugh. Early American Architecture. New York: Oxford University Press, 1952.

Phillips, Morgan, and Selwyn, Judith, Epoxies for Wood Repairs in Historic Buildings. Washington, DC: Technical Preservation Ser vices, U.S. Department of the Interior (Government Printing Office, Stock No. 024-016-00095-1), 1978.

Rehab Right. Oakland, California: City of Oakland Planning Depart ment, 1978 (pp. 78-83).

"Sealing Leaky Windows." Old House Journal (no. 1, 1973): 5.

Smith, Baird M, "Preservation Briefs: 3 Conserving Energy in Historic Buildings," Washington, DC: Technical Preservation Services, U.S.

Department of the Interior, 1978.

3 7 PRESERVATION

BRIEFS

Appropriate Methods for Reducing Lead-Paint Hazards in Historic Housing

Sharon C. Park, FAIA, and Douglas C. Hicks

National Park Service U.S. Department of the Interior

Lead-based paint, a toxic material, was widely used in North America on both the exteriors and interiors of buildings until well into the second half of the twentieth century. If a "historic" place is broadly defined in terms of time as having attained an age of fifty years, this means that almost every historic house contains some lead-based paint. In its deteriorated form, it produces paint chips and lead-laden dust particles that are a known health hazard to both children and adults. Children are particularly at risk when they ingest lead paint dust through direct hand-to-mouth contact and from toys or pacifiers. They are also at risk when they chew lead-painted surfaces in accessible locations. In addition to its presence in houses, leaded paint

Before After chips, lead dust, or lead-contaminated soil in play areas can elevate a child's blood lead level to a degree that measures to reduce and control the hazard should be undertaken (see Action Level Chart, page 6)

The premise of this Preservation Brief is that historic housing can be made lead-safe for children without removing significant decorative features and finishes, or architectural trimwork that may contribute to the building'S historic character (see fig. 1). Historic housing -encompassing private dwellings and all types of rental units-is necessarily the focus of this Brief because federal and state laws primarily address the hazards of lead and

Figure 1. A large-scale historic rehabilitation project incorporated sensitive lead-hazard reduction measures.

Interior walls and woodwork were cleaned, repaired, and repainted and compatible new floor coverings added. The total project was economically sound and undertaken in a careful manner that preserved the building's historic character. Photos:

Landmarks Design Associates.

lead-based paint in housing and day-care centers to protect the health of children under six years of age. Rarely are there mandated requirements for the removal of lead-based paint from non-residential buildings.

Ideally, most owners and managers should understand the health hazards created by lead-based paint and voluntarily control these hazards to protect young children. A stricter approach has been taken by some state and federal funding programs which have compliance requirements for identifying the problem, notifying tenants, and, in some cases, remedying lead hazards in housing (see Legislation Sidebar, pg.15). With new rules being written, and new products and approaches being developed, it is often difficult to find systematic and balanced methodologies for dealing with lead-based paint in historic properties.

This Preservation Brief is intended to serve as an introduction to the complex issue of historic lead-based paint and its management. It explains how to plan and implement lead-hazard control measures to strike a balance between preserving a historic building's significant materials and features and protecting human health and safety, as well as the environment. It is not meant to be a "how-to guide" for undertaking the work. Such a short-cut approach could easily result in creating a greater health risk, if proper precautions were not taken. Home renovators and construction workers should be aware that serious health problems can be caused by corning into contact with lead. For this reason, there are also laws to protect workers on the job site (see Worker Safety Sidebar,

pg. 4). Controlling the amount of waste containing lead based paint residue will also reduce the impact on the environment. All of these considerations must be weighed against the goal of providing housing that is safe for children.

Lead…