Roof Leaks and Water Damage

The trigger is evidence of water near the organ, not damage to the instrument. Church Music Dublin’s guidance for parishes, approved by the Diocesan Councils of the United Dioceses of Dublin and Glendalough in 2019, states that organs are particularly at risk from water damage from roof leaks and that if any evidence of water is found near the organ, advice should be sought from an organbuilder immediately. The Diocese of Chester’s technical advice separately calls leaking roofs a significant danger to organs, notes that a roof leak inside a chamber may go undetected for some time, and says any problems should be addressed very quickly.

Both are instructions to seek advice, not to take physical action on the instrument, and neither says anything about the electrical supply. Water seen or heard anywhere near the organ meets that trigger whether or not the instrument shows any change.

The sources named in organ-care guidance are all parts of the building, not parts of the organ. Dr David Knight, writing on church building maintenance in Historic Churches in 2003, states that a roof leak, possibly caused by one slipped tile, can cause expensive damage if it is over the organ, and that a blocked gutter on the outside wall by the organ chamber is a potential source of expensive damage. The British Institute of Organ Studies makes the same point about drips from a faulty roof or drain falling on leather and timber.

Patrick J. Murphy & Associates, an organbuilding firm in the United States, adds air-conditioner condenser units, plumbing and interior sprinkler systems to the roof as the water sources an owner should inspect regularly, and states that even small amounts of water can wreak havoc on an organ’s pipes, action, leather and wood.

These lists are inspection targets, not a ranking of how often each source fails. A plumbing failure can be as serious as a roof: the Pipe Organ Database record for Wicks Opus 67298 at the Chicago Temple attributes serious water damage on 6 May 1988 to an upstairs sink overflowing.

The Diocese of Chester’s advice is to inspect the chamber regularly so that a roof leak is detected promptly; it addresses prevention and detection only and gives no guidance on drying, humidity, mold or the electrical supply after a wetting event.

Knowing where the water came in, or seeing a stain, does not establish how far water has travelled inside the instrument. Windchests, leathered components, wiring and pipework are enclosed, and those paths are reachable only by someone permitted inside the instrument; the Organ Historical Trust of Australia’s conservation and maintenance guide restricts access to the organ interior to specialists. Patrick J. Murphy & Associates, recounting a 1981 water-damage project at St Mary’s Church, states that water damages pipes, action, leather and wood, and that excessive water will seep into even the most solidly constructed windchest, causing internal damage plus potential warping and glue failure in critical areas.

The practical consequence is that a water event is scoped from inside the instrument, not from the room. A description of the loss based only on what is visible can under-scope it.

Water changes leather and glued wood in ways that do not reverse when they dry. Conservation guidance on tanned leather describes water dissolving vegetable tannins and carrying them to the surface, where they darken and embrittle the material; repeated wetting and drying leaves leather permanently stiffer, and at high humidity soluble components can dissolve and then redeposit on the surface as humidity drops, restricting movement of the grain layer. The Canadian Conservation Institute states that wetting alum-tawed skin produces a hard, horny condition, and alum-tawed leather is the type supplier catalogs identify for organ valve, pallet and gusset leathers. This is guidance on leather objects generally; organ leather uses varying tannages and these sources do not test organ leather specifically.

Hide glue is softened by moisture, so joints may separate and veneers may lift, according to the American Institute for Conservation’s guidance on stabilizing wet furniture and wood. Organ windchests and reservoirs are hide-glued assemblies, which is why that mechanism matters here, but the guidance is written for furniture and wooden objects and does not name organs.

Cleaning water- or mold-affected leather is an irreversible action, and conservation guidance says degraded leather should be protected pending professional assessment rather than cleaned. For an owner, that means leaving wetted leather alone until the organbuilder has seen it.

Heritage-collections guidance gives specific numbers, and every one of them is written for collections generally rather than for pipe organs. The Canadian Conservation Institute’s Technical Bulletin 26, revised 2020, states that action is required within 48 hours after water intrusion to prevent mold onset, and that if relative humidity is above 60 per cent, air should be circulated and the space dehumidified to below 40 per cent until materials are dry. The same bulletin reports that at 80 to 90 per cent relative humidity mold growth is noticeable within one to five days, at 75 per cent between two weeks and three months, and that three-year experiments at 65 per cent showed no noticeable growth.

A separate flood-recovery booklet from the Minnesota Historical Society, dated June 1993, states that materials should be dried within 48 hours to prevent mold growth and that dehumidifiers should reduce humidity gradually to 50 to 55 per cent relative humidity. Those are targets for a drying space in a museum context, stated by a different source for a different scope than the Canadian figures, and the two sets are not interchangeable.

Two cautions attach to all of these figures for an organ. They describe collection materials generally, and the inside of a wetted organ can hold local moisture well above the room reading, so a hygrometer in the chamber does not settle whether mold is starting inside a windchest. And mold needs only moisture and nutrients to germinate, with growth accelerated by elevated temperature, poor air circulation, dim light and accumulated dirt, according to National Park Service guidance for museum collections.

Fast drying of thoroughly wetted unpainted wood causes irreversible damage, and drying wet wooden objects quickly causes warping and cracking. That is the Minnesota Historical Society’s statement for wooden objects generally, and the American Institute for Conservation’s wet-furniture guidance says the same in qualitative terms: wet wooden objects are dried slowly and not in direct heat. The National Park Service’s 2002 salvage sheet for object collections directs that wet wooden objects be air dried slowly and that wet leather, which it describes as fragile, be treated within 24 hours with a conservator consulted where flexibility must be retained. None of these sources gives a numeric drying rate or a relative-humidity target, and none addresses pipe organs or windchests.

The one organ-specific statement comes from Patrick J. Murphy & Associates: only after slow careful drying can the true damage be realized. It is an organbuilding firm’s own statement rather than a trade-body position, and it is qualitative; it gives no rate, target, time window or mold threshold.

The organ-care, conservation and organbuilding guidance available to owners gives no organ-specific number for either hazard: no relative-humidity or time threshold for mold onset after an organ has been wetted, and no safe drying rate or relative-humidity target for a wetted wooden windchest. Every numeric figure in the two sections above is heritage-collections guidance, and every organ-specific statement is qualitative. The two are not to be blended into one organ figure.

The two hazards pull in opposite directions. The collections thresholds press toward removing moisture quickly to stop mold, while wood- and furniture-conservation guidance warns that fast drying of thoroughly wetted wood warps and cracks it and that moisture-softened hide-glue joints may separate. No source reconciles the two for an organ, which is why how a wetted windchest is dried is an escalation trigger for a qualified organbuilder or conservator rather than a rule an owner can apply. The absence of an organ figure is not evidence that rapid drying is safe, and it is not evidence that the collections figures are wrong for organs; it is a scope caution.

If mold is already visible, the Canadian Conservation Institute sets area thresholds for professional remediation: 4 to 10 square metres of visible mold for large infestations, and above 10 square metres for extensive ones. Those thresholds are difficult for an owner to apply to an organ, because the visible area inside the instrument cannot be assessed without the interior access that conservation guidance restricts to specialists. The same bulletin notes that approximately 8 per cent of the population is predisposed to be affected by exposure to mold, which is a reason to keep people out of a moldy chamber while the decision is made.

The guidance written for electrical equipment in general does not accept drying out and switching on as a sequence. The National Electrical Manufacturers Association’s 2011 guideline Evaluating Water-Damaged Electrical Equipment states that electrical equipment exposed to water can be extremely hazardous if re-energized, that is, switched back on, without a proper evaluation carried out by qualified personnel. The Electrical Safety Authority of Ontario’s guideline for installations exposed to water, revised May 2025, states that allowing equipment and wiring to dry out and then re-energizing it is not a recommended practice, and distinguishes submerged from sprayed exposure with different requirements for each equipment class. Building Commission NSW advisory note 4/2023, written for flooding in New South Wales, requires inspection by a licensed electrical person and specified tests before an installation that was disconnected is energized again.

Taken together, those sources converge on a sequence rather than a numeric trigger: exposed equipment is not re-energized, isolation of the supply is verified, a qualified electrical person evaluates and tests it, and reconnection follows the authorization route of the jurisdiction, which in Ontario may mean written authorization from the Electrical Safety Authority before the utility reconnects. Each element is stated for general electrical installations by a manufacturers’ association or a single regulator; the three do not agree on procedural detail, none of them mentions a pipe organ, and requirements vary by jurisdiction.

A water event does not, by itself, establish an organ-specific rule that the instrument’s supply must be isolated, or say who may isolate it. No organ-specific source states such a rule; the closest organ-related material is a United Kingdom church insurer’s checklist that records evidence of moisture as a visual inspection finding. That absence is not evidence that isolating the supply is inappropriate. It means the question belongs to an electrical or fire authority in your jurisdiction, and this page does not supply the rule.

NEMA sorts water-exposed equipment into replace and recondition categories, placing motors and motor controls with solid-state components in the replace category, low-voltage electronic and signal equipment in the replace-or-return-to-manufacturer category, and wire listed for dry locations only in the replace category. NEMA names no organ component. Whether a particular organ’s blower motor, rectifier, low-voltage keying wiring or solid-state control equipment falls into those categories is a judgement for the qualified evaluator on site, not an organ rule.

For the owner, the decision is simpler than the evaluation: the instrument stays out of use until an organbuilder has advised, and the switching-on question stays with a qualified electrical person, because the general guidance above treats water-exposed equipment as not re-energized before evaluation.

A water event can become a project rather than a repair. At First Presbyterian Church of Kilgore, Texas, water damage traced to a damaged wall required restoration of the Choir Division, roughly 300 pipes of an organ of about 3,000. The work was reported in July 2021 as estimated at about three months and as involving deteriorated pipe pouch leather, a condition the report attributes partly to age rather than solely to the water.

Water damage is recorded on at least three named Wicks instruments: Opus 67298 of 1982 at First Methodist Church, the Chicago Temple, seriously damaged on 6 May 1988 when an upstairs sink overflowed; Opus 1228 of 1934 at St. Alphonsus Liguori in St. Louis, which suffered smoke and water damage; and the 1956 instrument at Morningside Presbyterian Church, Atlanta, described by its owner as a victim of severe water damage over the past 50 years. These cases establish what is possible, not how often it happens, and none of the three records identifies which component failed.

Where smoke or fire residue is present alongside the water, as the St. Louis record notes, the recovery picture changes; soot, fire residue and suppression agents are covered on Fire, Smoke and Suppression-System Damage.

A durability claim made for a chest action does not settle how a particular instrument fares in a water event. A 2019 organ dedication leaflet from St. Martin’s in the Desert Episcopal Church in Pahrump, Nevada repeats a claim, traceable to the manufacturer and its encyclopedia summary, that the Wicks Direct Electric chest action “is not affected by temperature or humidity”. That is a marketing-derived statement carried by a parish booklet, not an engineering finding.

The three water-damage records above stand separately on their own sources and dates. They do not show that Wicks instruments are more or less vulnerable to water than other builders’ instruments, and because none identifies the failed component, they neither confirm nor refute the claim about the chest action. One side is an attributed self-description; the other is a set of documented incidents, and neither settles the other.

Take the instrument out of use and seek an organbuilder’s advice immediately; that is the diocesan instruction, and it is triggered by evidence of water, not by damage. Do not go inside the instrument to look, because access to the organ interior is restricted to specialists, and do not begin drying it by any method until the organbuilder or conservator has decided how, for the reasons in the drying section. If mold is visible, keep people out of the chamber while that decision is made.

The electrical supply is a separate question for a qualified electrical person under your jurisdiction’s rules, and this page does not tell you whether or how to isolate it.

The building-fabric water source has to be found and fixed by whoever maintains the building, or the water returns; that is the point of the inspection advice from Knight, the Diocese of Chester and Patrick J. Murphy & Associates.

Record what you saw, where and when, before anything is moved or dried. That record is what you pass to the organbuilder, and what to record before calling a technician covers it in detail.

Patrick J. Murphy & Associates also advises annual professional appraisals for insurance purposes and separate coverage if an organ is removed for storage or renovation; that is the firm’s own advice in United States insurance terms rather than an insurer’s or association’s requirement.

For the rest of the emergency picture, including rodent contamination and the fire and suppression cases, start at Pipe Organ Repair and Emergency Guidance.