The project

In Aberdeen, ABN7 Architects undertook the full renovation of an early 20th century building. Previously, three flats, the project involved converting the building into two flats, with particular emphasis on the improvement of energy efficiency and air quality throughout the site.

Goals

• Total building refurbishment
  
• Energy efficiency and air quality improvements
  
• Maintain the original structure and features of the building
  
• Minimal damage during install  
  

Why Sisalwool?

In older buildings, it is vital to use breathable insulation that can deal with any moisture in the existing walls. This retrofit included Aberdeen’s infamous granite walls. Being an area known for its high levels of rainfall, and unfortunately, granite absorbs a lot of that water. Thankfully, the Sisalwool team, many of whom have grown up in Scotland and are accustomed to this kind of thing, had breathability in mind when our product was developed. Sisalwool is a natural fibre insulation with top-grade breathability, making it the perfect choice for this retrofit. 

Furthermore, Sisalwool aids in energy efficiency of buildings by improving thermal regulation, keeping buildings cool during the summer and cosy during the winter. Ultimately, this will reduce reliance on fossil fuels and lower energy bills.

Excellent breathability and thermal efficiency aside, Sisalwool also offers Grade A sound absorption for maximum peace and privacy, is made from natural and non-toxic fibres, is non-irritating and easy to install, resulting in minimal disruption to the building’s original structures. 

The team were able to install Sisalwool quickly and easily, with the peace of mind that once Sisalwool goes in, everything is taken care of.

Benefits

• Improved indoor air quality
  
• Increased energy efficiency
  
• Grade A sound absorption
  
• Minimal/no damage done to building fabric
  
• Quick installation time
  

Installation

Installing Sisalwool is a straightforward process and was vital for this retrofit to respect the integrity of the building’s original structure while delivering the highest performance possible. 

The internal walls were first stripped back. A new 4x2 stud wall was constructed, with Sisalwool 100mm friction-fitted between the studs. To help tackle cold bridging, a 35 mm wood-fibre board was fixed over the frame, followed by the application of an intelligent membrane. A service cavity was then created, finished with plasterboard for a clean interior look.

In areas where the original timber studs were in good condition, they were retained. Sisalwool was friction-fitted directly between them, preserving original features while still improving insulation.

For the sloped roof, the existing structure was carefully stripped back. Sisalwool 100 was installed between the rafters, maintaining a 50 mm ventilation gap between the insulation and the sarking board to allow for airflow.

In the loft, Sisalwool 100 was installed both between and over the joists for complete coverage. Underfloor insulation followed a similar approach, with Sisalwool friction-fitted snugly between the joists to reduce heat loss from below - even fitting in the triangle spaces around the turrets!

The result?

A warm, breathable, and energy-efficient home with minimal disruption to its historic fabric and best-in-class sound absorption.

“Sisalwool is easy to cut, fast to install and safe to work. It’s bloody brilliant! Also, there was basically no waste as off-cuts could be used elsewhere, unlike PIR.”