Pavadry and Energy Efficiency

NBT Updates

Natural Building Technologies are close to completing the installation phase of a research project with Willmott Dixon using our BBA certified Pavadry internal wall insulation.

Joining forces with the Building Research Establishment (BRE), Willmott Dixon and Letchworth Garden City Heritage Foundation have retrofitted a 1920s semi-detached home as part of a project to show how traditional properties can be made more energy efficient. Pavadry was included among a number of robust, complimentary products chosen to deliver a simple cost-effective approach that compliments the existing building and avoids over-complication.

Retrofitting Energy Efficiency

The building will be monitored over the next 12 months to see how energy use is affected by the retrofit. The aim is to demonstrate how much energy and money can be saved by those living in traditional dwellings without adversely affecting occupant comfort or the building. Making heritage homes more energy efficient, whilst retaining the character and aesthetics of the building is also one of the challenges the project seeks to overcome.

BRE Assessments

The building was assessed by BRE with co-heating and airtightness tests to record the baseline energy performance. The data will be used to gauge how much the property improves following the work. Once complete, BRE will carry out analysis on a number of factors such as energy use and internal conditions, the performance of various design features and the experience of the property’s residents. This will be compared against a similar property which does not have these modifications.

The Benefits of Pavadry

Natural Building Technologies are sponsoring the project by providing Pavadry internal wall insulation and site support. Pavadry was chosen due to its ability to promote drying of the wall internally while managing the moisture generated by the occupants, thus eliminating harmful build ups of moisture within traditional walls. The solidity it affords the internal surface was also a consideration.


Ease of Installation

Initial feedback from the installation phase is good. Rokzen Ltd who have undertaken the works on behalf of Willmott Dixon, have remarked on the ease of installation, saying it is “like tiling with giant tiles”. As specialist IWI contractors, they have particularly noted the time savings relative to systems based on lightweight insulation with vapour barriers. There is reduced measuring up, elimination of a whole stage of works (VCL installation), and simplification of window reveal detailing.

BBA Certified

Pavadry has recently received BBA certification which has rubber stamped NBT’s rigorous approach to product specification and assessment. Pavadry is the first and only IWI system that has been assessed by BBA according to BS EN 15026, the relatively new assessment methodology which is now widely recognised as the only appropriate standard for IWI assessment. BBA is recognised by building control, government departments, architects, local authorities, specifiers, and industry insurers.

The standard assesses the impact of a much wider range of moisture transfer mechanisms and sources than alternative methods, including the impact of rain on the external surface, which is now understood to be a much more significant contributor to moisture levels in solid masonry than occupancy related moisture.

Products used in this project…