Deep hempcrete retrofit


Deep Hempcrete Retrofit to an Oceanfront Residence.

Project Details

Location: Skerries, County Dublin, Ireland.
ProjectType: Two storey, 1200 sq. ft. semi detached oceanfront residence.
Project Duration: 3 weeks.
ProjectSummary: Interior breathable cladding of exterior walls with 90 mm Hempbuild Isohemp hempcrete blocks to increase insulation and thermal mass performance of a large yet old semi detached oceanfront residence whilst dealing with moisture issues.

Methods of construction specific to this project

Cladding internal face of external brick walls with 90 mm hempcrete block to combat moisture and thermal issues brought about by  the application of non breathable external plasters. The result was a trapping moisture which caused internal bricks to become saturated and degrade significantly over many years. Using hempcrete blocks provided a solution as insulation that will manage moisture built up, allowed the internal brick to breath and continue to dry out for the future duration of the structures habitation and use.  

  • All old internal plaster was removed, exposing brick.
  • All dust and debri from surface of brick was removed. 
  • All services were run on surface to limit  vibration risks of damage to original structure.
  • All electrical sockets and services were cut out of the hempcrete blocks.
  • The  90 mm hempcrete blocks were applied using ISO hemp adhesive and galvanised wall ties to ensure bond to brick and mechanical fixing to brick.
  • 10mm of PCS breathable plaster was applied to the hempcrete blocks in 2 coats leaving a high quality surface to paint directly on to.
  • Ready to paint once fully dry, 2-3 weeks.

Materials used

  • Hempbuild 90 mm Isohemp Hempcrete Blocks
  • Isohemp Mortar Adhesive
  • PCS Interior Plaster
  • Tools & Accessories
  • Galvanised wall tiesProject

Additional construction methods available on this type of project

Although space was an issue on this project in most cases a 120 mm block could have been used to increase thermal phase shifts and insulation values internally. A range of plasters and finishes could be used. Traditional sand and lime mixes may be used. Clay based plasters and paints maybe used. Internal wood cladding may be used.

90 mm Hempbuild Isohemp Hempcrete Block Advantages

  • The 90 mm hempcrete block is not bulky, thus no significant loss of living space.
  • Quick and easy implementation.
  • Easy to fix items directly to the walls, pictures, kitchen units, etc.
  • Thermal regulation: The  hemp 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.
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