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Home > Publications > Historic New England Magazine > Fall 2004 > The North Wind Doth Blow

The North Wind Doth Blow

ABOVE A solid blanket of rooftop snow indicates a cool attic, which will prevent ice dams.

BELOW Poorly maintained exterior elements invite moisture infiltration and rot.

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ABOVE Icicles at the roof line suggest ice dam conditions.
BELOW These wooden exterior storm windows blend unobtrusively with the historic character of the house.

New England's historic homes are distinguished survivors, having sheltered generations of occupants through countless blizzards and ice storms. As hardy as they have proven to be, though, they must be well maintained to keep performing at their peak. Fall is the ideal time to carry out preventive maintenance so that bad weather will not turn minor problems into big ones.

Winter exposes the exterior of a house to more moisture, and for longer periods, than other seasons. Trim tree limbs at least six away feet from the roof and prune shrubs at least two feet back from the side walls. This will ensure adequate air flow around the house and allow it to dry quickly after wet weather. Now is also the time to remove dead branches that might fall and cause damage in a storm. To minimize the build up of snow against wood siding, carefully lower the grade level around the house to expose three to six inches of the foundation. Divert water away from the foundation by grading soil down and away from the house.

To prevent damaging moisture from entering, breaches in the building envelope should be repaired. Pay particular attention to open mortar joints in chimneys, foundations, and other masonry, compromised roof coverings or flashing, deteriorated or missing siding and trim, broken windows, and areas of bare wood or failing paint. To divert roof runoff from streaming down the sidewalls, clear debris from gutters and downspouts, repair open joints between gutters, and replace damaged sections or supporting hardware. Adjust the gutters' pitch to ensure proper water flow.

Maintenance projects may affect significant historic features and should therefore be carried out to preserve as much as possible of the existing building material. Only elements that have deteriorated beyond repair should be replaced, with the new material matching the old in appearance, composition, dimension, and fastening techniques. Employ the gentlest methods to achieve your objectives in order to avoid damaging historic features.

To block cold air, close gaps between exterior architectural elements, and tighten window and door openings. Clear dirt and deteriorated caulk from open gaps between exterior siding and trim material and seal with new caulking. Polysulfide caulking is recommended, as it forms a paintable, watertight, long-lasting bond. Caulk junctures between wood elements and masonry, particularly along the top of the foundation. Open joints along the underside of clapboards, shingles, and window and door casings should not be caulked, however, as they allow water vapor to escape, an important function in an otherwise tight house.

Among the most effective ways to minimize drafts and heat loss is to install storm windows and doors. Tight-fitting and well-constructed exterior storm windows are recommended over interior installations that can cause condensation and damage to the wood. Exterior storm windows also protect the historic windows. Homeowners who object to the appearance of exterior storm windows can use wooden ones to soften their visual effect or camouflage metal versions by painting them to match the window casings.

Block drafts further by adding weatherstripping to loose-fitting windows and doors. A variety of weatherstripping options is available, including traditional types, such as strip felt, bronze spring strip, and bronze V-strip, as well as newer versions, such as rubber, plastic, and adhesive-backed foam. Metal or plastic spring strip versions are an excellent choice for most uses, as they are relatively easy to install, effective, and visually unobtrusive. Install pulley seals to block air from leaking though window sash pulley slots and door sweeps to seal the gap between the door and threshold. Historic windows that are kept in good repair and tightened with weatherstripping and exterior storms can easily match the thermal performance of replacement windows.

Ice dams are one of the most disastrous kinds of winter-weather damage. They form when a warm roof melts the underside of the snow above, which then partially refreezes to create a pocket of trapped water. This water can back up under roof shingles and flow into the house, damaging structural members, plaster, and other historic features. Snow melting from the upper portions of your roof in freezing weather and refreezing as a mass of ice and icicles along the edge of the roof indicates that this condition may be present. To prevent ice dams, keep the attic cold so that rising heat cannot warm the roof and melt the snow and ice above. Thoroughly insulate the attic floor, but not the roof, and ventilate the attic with louvered or screened openings. Replace insufficient, wet, compressed, or settled insulation. Tighten up the opening around the access door or hatch, seal off gaps around plumbing or wiring, and wrap insulation around heating ducts in the attic.

It is not typically advisable to insulate side walls of historic houses. Blown-in or other loose insulation materials, such as urea formaldehyde foam or cellulose, are particularly inappropriate for use in historic homes, as they tend to introduce or trap moisture inside the walls. To prevent air infiltration, caulk open joints inside exterior walls, especially around windows and doors. Where you can access them, insulate pipes that run through exterior walls with lengths of extruded foam made for this purpose, taking care to seal the insulation well with duct or insulating tape.

Finally, in the cellar, repoint the foundation as necessary, and seal open joints with caulk. Add weatherstripping to the door from the living space to the cellar, and tighten up the bulkhead leading to the exterior of the house. Insulation added to the ceiling of the cellar and crawlspaces can also help to keep the living space warm.

For nine months of every year, most New Englanders forget just how bitter our winters can be. Unavoidably, though, the mild weather and colorful display we enjoy in the fall will give way to another long bout of snow, wind, and ice. With sensitive and timely winterization, your historic house will be snug and warm for this and many more winters to come.

-Roberta Lane
Stewardship Manager

The North Wind Doth Blow