It’s been a bad summer for historic churches in Hudson. First, Emanuel Lutheran was vinyl-sided--with the knowledge and consent of its congregation. Now, there’s word that the masons at work on the First Presbyterian Church may be using an inappropriate mortar mix--without the knowledge and consent of the church’s small but very preservation-conscious congregation.
The church awarded the masonry repair project to the lowest bidder with the full expectation that the job would be done according to specifications. Since grant money is involved, strict adherence to established preservation standards is a requirement. The church even hired a project manager to oversee the work and make certain it was being done properly. But earlier this week, local preservation specialists not involved with the project reported to a church member that the mortar being used didn’t look right. Some surreptitious investigation at the work site discovered bags of Quikrete—a “just-add-water” mortar mix of sand and cement available at places like Lowe’s.
Mortar is critical in masonry repairs to historic buildings. New mortar needs to match the original mortar for aesthetic reasons--so that it’s the same color and looks the same as the original mortar--and for very important physical reasons. The mortar cannot be harder than the stone or brick it is used with. Historic masonry buildings were designed to absorb water and then release it. The mortar used in historic buildings was lime mortar, which allows water to pass in and out of the joints, so it doesn’t get trapped in the brick or stone. Mortar containing Portland cement, which wasn’t used in the United States until the 1930s, is very hard--harder than stone or historic brick--and it is less permeable than lime mortar. It doesn’t wick water out of the walls, so water gets trapped in the stone or brick, causing it to deteriorate. The bitter irony is that the masonry repairs being made on the church now are to correct the problems caused by repointing done with inappropriate mortar in the past.
Representatives of the church are investigating the situation.