One of the most beautiful uses of Earth Pigments is in lime plaster. However, for plaster enthusiasts, the rich body and smooth application is worth the effort.A Provence lime plaster similar to our Natural Sienna. You’ll need to be patient though, as high calcium lime needs to stay in putty for for at least 3 months prior to use. Plastering with any hydrated lime can give the appearance of frosting a cake.įor an even richer plaster, try high calcium lime. Hydrated limes are rich in texture, with a lush, buttery feel. We recommend presoaking the lime for up to 16 hours prior for use in plasters. Type S lime benefits from being pre-wetted before application, but can be used directly from the bag, an impossible feat with high calcium. This product is widely available, and is very affordable, especially in bulk. Of all the hydrated limes, the dolomitic lime meeting the ASTM standard of Type S is the most production-ready plaster in the US. Unfortunately, its no longer available on the market, but that’s another story. Sold as two different products - a double hydrate agricultural lime and a Type S building lime, this dolomitic lime product is suitable for lime plaster. The shortened set and cure time of the hydraulic lime plaster allowed us to apply two coats before the temperatures dropped below freezing.įor the interior, we chose a local lime from Lee, MA. Due to Covid-19, plastering came 2 months later than we’d planned. Given our latitude, the decreased setting time and curing time was also a bonus. By shifting from a hydrated lime to a hydraulic lime, we are able to take advantage of increased hardness. In cases such as this where overhangs are shallow and buildings are tall, a little extra protection goes a long way. Proper detailing, especially around bulk wetting - rain drops, drip edges, and capillary wetting - is essential for the life of any finish. This combination is hard on all finish surfaces, and plaster is no exception. This lime was imported from France, and will cure more quickly, be harder on the wall, and have more resistance to erosion.Įxposed facades, like the one shown here are common throughout New England, provide little protection from wind, rain, snow, hail, and sun. High calcium lime is less abundant but can also be found, and is highly prized among many plasterers.įor the Hempcrete House in Goshen, MA, we had 3 factors that dictated our choice of lime: large facades with significant exposure on the windward side, a wet and harsh climate, and an impending frost date.įor these reasons, we chose to install a NHL 3.5 hydraulic lime plaster. Produced into Type S lime, it’s seen as a valuable material in the plastering and mortar markets, so is easy to find at mason supply shops and building supply stores. The distinguishing characteristic is the percentage of Magnesium Carbonate in the limestone.ĭolomitic limestone is quite common. The differences between high calcium, magnesium, and dolomitic limestone are shown below, as determined by ASTM. In the US, these limes are generally referred to as Hydrated Limes. In the US and Canada, Pure Limes dominate, though the term Pure Lime is a bit of misnomer. These variations in lime can be used to good effect, depending on your needs as a builder or designer. These additional minerals affect the properties resulting from limestone production. Many limestone deposits have other minerals in addition to pure calcium carbonate, or lime. Within the boundaries of lime is a surprisingly complex and varied material, depending on the constituent elements of the material.
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