Traditional and Historic buildings
Hempcrete was first developed in France as a method of adding thermal performance to medieval timber frame buildings whilst allowing the historic building fabric to continue working in the way it was intended to. Hempcrete is a vapour permeable material, and the hemp shiv is a hard cellulose material very similar to timber, so it “manages” moisture as a similar rate to existing wooden elements within the structure, preventing a build-up of moisture against vulnerable historic building fabric.
For this reason, about half of the work we do is repairing and upgrading the thermal performance of traditional, or historically important buildings. The most common applications of hempcrete in this field is as in-fill to historic timber frames or casting against existing stone or brick walls. English Heritage and SPAB have both highlighted hempcrete as one of the most suitable materials for improving the thermal performance of our architectural heritage.
As well as its vapour permeability (“breathability”), hempcrete offers a unique application method which also makes it perfect for very old buildings: As a wet-mixed, loose fill material which sets and holds its own shape, hempcrete can be applied against uneven walls, and within irregular timber frame panels, or strange-shaped voids in the wall, and act to fill every last space with its highly thermally effective mixture of insulation and thermal mass. The surface of the hempcrete (whatever shape) can then be plastered, bringing a very high level airtightness to the thermal envelope of the building.
Compare this to the process of installing regular shaped panels or rolls of lightweight insulation against, around or within an irregular-shaped historic frame or masonry wall: No amount of cutting will achieve exactly the right shape to fit the building, and the resulting insulation layer will be very difficult to make airtight.
Because of this loose fill method hempcrete also has aesthetic advantages over regular-shaped panels in an old building. Hempcrete can be applied to the original structure in a way that follows the curves and irregular shapes of the existing fabric, meaning that the final surface of the hempcrete retains the character of the old building, without the need for any further processes or faking of “old character details.”
Because every historic building is unique, there is not a one-size-fits-all solution to adding hempcrete to your historic building. It’s important that a bespoke solution is designed / adapted on site to meet the specific needs of your building, and that the hempcrete installation (and any other thermal upgrades) are considered within the context of the other building elements and systems to ensure a holistic approach which maximises thermal performance while protecting and maintaining the historic building fabric.
In addition to being the renowned industry leader when it comes to repairing and upgrading traditional and historic buildings with hempcrete, Hemp-LimeConstruct also has the expertise in house to undertake, timber frame repairs, traditional roofing, lime and clay plastering, stone and brick repairs using traditional mortars, cob repairs, the construction of limecrete or clay floors and the use of a wide range of building limes, which allow us to work effectively within this sector however large or small the project.
To discuss your traditional or historic building with an expert, contact us.
To see some examples of our previous work in this area visit the gallery.