Preservation projects are nothing like new construction since there are unknowns. Because they are normally bid just like new construction, the surprises that arise later make preservation projects more expensive. Too often risk mitigation on restoration projects means increasing the budget 50% or more. This isn't necessary. By reserving the first month of the project for on-the-scaffold investigations by the conservators with the key members of each team of tradesmen, optimal details can be developed and any training needed to show tradesmen new skills can occur before contractors finalize their bids for the project.
As this 1917 military structure was re-purposed into offices, the wood graining of the formwork for the concrete pours was repaired with grout and faux bois graining tools and the surfaces were casein painted in a tone that matched the reaction of high pH lime from the original concrete pour attacking the oil from the formwork and the tannins in the wood, creating a visibly soft and inviting interior to a concrete and glass structure.
This is part of larger series on carbon fiber (CF). If you are just joining this blog now, please take a moment to review the previous carbon fiber repair posts. In initial attempts to determine which CF cloths and resins to use, we reviewed loads of technical literature. Too often though it was focused… Continue reading Carbon Fiber: From Woodwork to Masonry
Mortar matching is often seen as difficult to do, but once you understand that historic mortars primarily came from local sources, one need only look to the local geology including at roadside cuts to recognize the aggregates of a sand in their former condition. This is the wonder of the fractal nature of stone reduced to sand. And often the sand you seek is right beneath your feet!
Google Maps for mortar matching?! Go local when seeking to match historic mortars as the sand you seek may well be under your feet. If you need to go off site, look nearby. When the mortar analysis checkbox is clicked by sending away for a report that does not give you an exactly matching source (without relying on tweaks from pigments that may not be stable and will change the lime-sand ratio of a mortar and its working properties), your money is being wasted and your building is not getting the best treatment.
Sand is not sand is not sand. Often when people are having stucco or plaster application problems (although the same can happen with bricklaying mortar), it turns out the aggregate is to blame. In short, it is not as simple as accepting whatever is at the local masonry supply house. Nor for that matter if… Continue reading What you need to learn from a mortar analysis about aggregates and ratios