Those involved in the restoration and preservation of the nearly 250-year-old Fort Pitt Block House received some good news Thursday when X-rays revealed less internal deterioration than originally anticipated to two tiers of gun loop timbers.
"The X-ray exam showed that the gun loops did not have any significant internal wood deterioration and did not require complicated internal structural repairs," said Dirk Taylor, the structural engineer overseeing the Block House restoration project.
"Rather, wood deterioration worked its way from the exterior surfaces inward, requiring only relatively simple repairs applied to the surface."
The blockhouse was built as part of Fort Pitt, which was located at what is now Pittsburgh's Point State Park. The fort, constructed in the last years of the French and Indian War, was the largest British fortification in North America.
Much of the stone foundation, brick and timber in the two-story blockhouse are original. The mostly solid walls of the structure are punctuated by two rows of wooden-framed gun ports that gave defenders stationed in the blockhouse a 360-degree view around the building.
As the Block House approaches its 250th anniversary in 2014, the Fort Pitt Society initiated a restoration and preservation project earlier this year whose first priority was to insure the stability of the gun loop timbers, the most fragile element of the structure.
The main issue that remains is how to delicately work the necessary structural repairs into the wood without harming the appearance of the gun loops.
Allegheny Restoration was selected to handle that specialized aspect of the work. Structural epoxy will be injected into any voids that have formed in the gun loops to restore their structural integrity. The few areas identified as severely deteriorated will be replaced and a small steel brace will be installed in one section of the lower gun loop.
While on site, Allegheny Restoration will also repair and clean the wood shingle roof of the Block House before applying it with preservative.
Starting this week, the Block House will be closed from Tuesdays through Fridays so that the technicians can complete the preservation of the timbers.
Michael A. Fuoco: firstname.lastname@example.org or 412-263-1968.