In this on‑site walkthrough, Jackson Digney of Enduro Builders explains the role of rammed earth walls as internal thermal mass in a Passive House. He describes how placing thermal mass inside the building’s airtight envelope maximizes temperature regulation and avoids thermal bridges, offering cost‑effective energy performance. Digney compares common thermal mass options—brick, block, tilt‑up concrete—and argues that rammed earth provides superior aesthetics, tactile appeal, and a low carbon footprint due to its simple mix of fines, aggregates, minimal cement, and water, compacted with pneumatic rammers in colored layers. He outlines the construction sequence, noting that after the rammed earth wall the next phases are steelwork and timber framing, and expresses enthusiasm for showcasing those future stages.
Chapters
Hi, it's Jackson Digney at Enduro Builders. We are at the display home and we're talking about rammed earth walls. So rammed earth walls are a form of thermal mass that you can put in a house, and one of the key reasons for putting thermal mass into a house is that it can act as a temperature regulator. A lot of older, leakier homes get away with Being leaky because they have a lot of thermal mass in them. Now imagine if you took that same home and made it airtight, then you're actually getting the real benefit from thermal mass, which is that it regulates the temperature throughout the year regardless of whether it's hot or cold outside. So the rammed earth wall in this house has been set up so that it's entirely inside the thermal envelope of the house. There's a few reasons for this. The first one is it avoids us having to have any thermal bridges, which is really important in Passive House. The second reason is that by having the thermal mass entirely inside the thermal envelope of the house, you get the maximum benefit from the money that was spent putting it here. And it's an important aspect when you're working out where to have thermal mass in the house, is balancing that against budget. And so So one of the key things that you can do to make sure that you get the best bang for your buck with your home is putting your thermal mass inside the thermal envelope of the house and protecting it from the cold or hot weather outside. So sometimes people ask, what are the other options for thermal mass? So some of the basic options for thermal mass are brick or block, tilt-up concrete, or rammed earth. The reason that we've picked rammed earth is that it's a beautiful end product that looks fantastic, and when people come into the house, they usually can't help but they want to touch it. And has a reasonably low carbon footprint in that the materials are essentially a mixture of fines and aggregates that is mixed with a very small amount of cement and some water. And then the material is rammed using pneumatic rammers, and in this case it's been rammed in different color layers to create a bit of texture and interest. Now that the rammed earth wall is up, the next stage is steelwork and then the timber framing. So I look forward to coming back and showing you these stages of building a Passive House.
