Retrofitting – A series in progress 

Blog By Dermot Moore
Frequently Asked Questions

We receive a heap of questions about hemp’s application in retrofitting. From whether hemp is water-resistant. Does it protect against mould? Is it 100% safe to handle? The resounding answer is yes. Below we’ve briefly outlined why. However, over the coming weeks, we’ll delve into each question and ask our experts to help us dig deeper into each area. 

Conventional Costs

Conventional retrofits usually involve the installation of dense insulation materials behind denser plasterboard. When using this form of sealing heat is kept in and the space airtight, which leads to the indoor space lacking in permeability and breathability. This can increase indoor air humidity and mould growth. Ailments can harm skin, airways and eyes. Current retrofit systems involve cycles of toxic instalments, where new versions of the same mould-cultivating airway-suppressing materials replace the initial retrofit. These intended restorative measures are often more costly than relief, as both spare time and money are spent along with harm to human health. 

Hemp Solutions

Hemp and biomaterials, in general, will be conventional in the future, and rightly so. Insulating with hemp allows vapour to pass between interiors and exteriors while retaining ideal levels of heat and moisture that do not harm skin, eyes or respiration. This is due to both its density and consistency of non-hazardous material. 

  • Retrofitting with hemp won’t be as effective if installed with solid, nonpermeable plasterboard or similar materials. Non-breathable material allows pockets of condensation to harbour and propagate mould. 
  •  Exposed hemp insulation or hemp covered by plywood reduces the risks of moisture accumulation behind interior walls. Using our Bio Board adds an extra layer of breathable construction board. 
  •  A further step that can be taken to ensure mould resistance is to combine hemp with lime. Hemp and lime can be exposed to even higher humidity levels before mould growth becomes a risk.

Hemp is safe to handle without protective equipment, but small particles, like any fibrous material, might cause eye irritation during installation. Therefore, we always recommend wearing eye protection. 

Most importantly, the successful application of hemp in any construction, be it retrofit or new, requires expert advice and an agreed approach from all parties (architect, construction team, homeowner, sustainability advisors, risk assessors etc.). 

If you have a retrofitting question that you’d like answered by our team, get in touch with Dermot, and we’ll make sure that we put it to them. 


Further Sources

What causes mould growth behind plasterboard?

Causes of condensation and black mould

Preventing damp and mould

Can damp and mould affect my health?