Shoring It Up, Sealing It Tightly

Of course, the layout isn't the only hurdle to overcome in converting a barn. Many are in poor shape because busy farmers of limited means struggled to maintain these massive structures. The biggest problems tend to be in foundations, typically made of loose-laid dry stone. Since barns rarely have in-ground drainage, wet soil gradually works its way between the stones, loosening them and causing the building to shift. The timbers themselves — particularly the rafters — are also vulnerable to water damage. Cracks in the roof boards let in rain, which runs into the walls and causes them to warp and bulge over time. Then there are the bugs, like the termites and powder post beetles that were discovered in the Carlisle barn. There, at least, the treatment was simple: Exterminators sprayed on a nontoxic borate, which poisons the insects' food supply.



Another issue is how to create an energy-efficient and weather-tight home while preserving the barn structure's character. A popular solution is to sheathe the exterior with structural insulated panels, sealing and insulating the barn from the outside. The original barn-board sheathing, posts, and beams can then be left exposed for the interior walls and ceiling, adding to the rustic feeling of the house; or, for a more finished look, the barn boards can be covered over with finished drywall between the exposed posts.

The energy-efficient plan for Carlisle, however, preserves both the barn's interior and exterior. Tom Silva will install 2x3s turned flat, on 16-inch centers, between the posts and beams, spray between and behind them with polyurethane foam, then apply drywall on top. The resulting walls will leave 1 1/2 inches of the timbers showing.



While such challenges don't necessarily rule out a barn or other outbuilding for conversion, they can add considerably to the cost. For a large barn like the one in Carlisle, treating an insect infestation runs about $500. But jacking up the structure, replacing its foundation, and adding an in-ground curtain drain around its perimeter can cost over $25,000 (and considerably more if the new foundation is stone). The good news is that if a barn qualifies as a historic structure, homeowners may be eligible for tax relief. The federal Rehabilitation Tax Credit offers a tax reduction based on a percentage of the money spent to fix up a historic structure. In addition, many states offer income-tax credits or property-tax abatements to homeowners who rehabilitate old buildings.

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