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Exterior Hempcrete Insulation to a Semi Detached Residence

Project Details

Location: Veenendaal, Netherlands.
Project Type: Two Storey Detached Residence with Rear Extension.
Project Duration: 5 weeks.
Project Summary: Exterior insulation to side and rear of the building and extension using 150mm Hempbuild Isohemp hempcrete blocks and Isohemp supporting brackets at flat roof detail area. The hempcrete blocks provide extra thermal insulation to the side and rear of the house, where the prevailing weather systems were having an adverse effect on the thermal performance of the building. 

Methods of construction specific to this project.

This is a highly resilient exterior insulation system, and thanks to its high mechanical strength, the 150 mm block is ideal for this type of project. The exterior painted surface of the building was scraped and roughed up to provide a key for the adhesive to create a good bond with the hempcrete blocks. Next, a stone plinth was laid along the ground to carry the hempblocks and match the front of the house. The 150 mm blocks are then built/fixed against the exterior of the wall using Isohemp adhesive and galvanized wall ties ensuring a strong and lasting bond. 

  • 150mm carrier brackets were used where necessary to support the new wall.  

  • Finally a 25mm coat of breathable sand and lime plaster was applied in two coats - a straightening scratch coat and a 10mm top coat, to provide a fine elegant finish. 

  • N.B. The exposed edge of the hempcrete block was later weathered with a 25mm coat of breathable sand and lime plaster. 

Materials used:

  • 150mm Hempbuild Isohemp hempcrete blocks

  • Isohemp mortar adhesive

  • Hydraulic lime 

  • Washed plastering sand

  • 150mm Isohemp carrier brackets

  • 150mm Isohemp reinforced hempcrete lintels

Additional construction methods available on this project.

While Hempbuild’s Isohemp hempcrete blocks are an excellent substrate for breathable natural plasters, its also ideal for cladding that can be directly attached to the insulating blocks, accordingly, avoiding the creation of potential thermal bridges.

Hempbuild’s Isohemp hempcrete blocks are available in various thicknesses, providing options for larger or smaller blocks to be used as per the requirements of the client, > thermal mass, acoustics, etc.

A range of plasters and finishes could be used on the exterior facade. Traditional sand and lime mixes may be used. Clay based plasters and paints maybe used or external wood cladding may be used, all depending on the specification from the client and architect.

150 mm Hempbuild Isohemp Hempcrete Block Advantages.

  • Quick and easy implementation, lightweight, significant thermal mass.

  • Easy and problem free to fix items directly to the wall, gutters, lights, etc.

  • Thermal regulation: The hempcrete block naturally stores and dissipates accumulated heat, which help to keep the house cool in summer and warm in winter.

  • Natural humidity regulation: Thanks to its high permeability to water vapour, the hemp block acts as a moisture buffer. Deals well with moisture and dampness in old walls.

  • Mold resistant: Hemp has a strong natural resistance to mold and bacteria.

  • Environmentally friendly: Our hempblocks are carbon negative and contain no VOC's or harmful toxins for inhabitants.

  • Fire resistant: It is inflammable and does not release toxic gases during its combustion.