Category > Building

Handwerker_Logo_EN_tradesperson

I qualified as a Passivhaus Tradesperson.

Although I’m a Passivhaus Designer already I’m looking at doing some training for contractors around low energy buildings. For research and some top up learning I went on the BRE Passivhaus Tradesperson course along with Bill Butcher from Green Building Store.

The course is a slimmed down version of the Designer course and I was surprised at the level of technical content, although the exam was much easier and multiple choice. The BRE delivered a translated version of the PHI German material which was dry. There was a lot of powerpoint, no physical example materials, and mainly German project examples.

Thankfully I passed the exam. In German this makes me a Passivhaus Handwerker, a
somewhat dubious title!

Whole house balanced ventilation is relatively new in the UK and many of the problems reported by users relate back to poor installation and commissioning.

To help me design better systems and to find out first hand about reality on site I decided to dust off my tool bag and got the opportunity to install this system at Cocreate’s Whipley Lodge Passivhaus project. I’ve put down some of my experiences to help me remember, and to help other designers and anyone considering installing.

Design lessons

  • Make sure the rigid connection between the unit and the external wall allow for installation. At least one bend is required here. Very short ducts have to be installed before the unit and this needs to be clear in design information.
  • Preference for fan units that have internal frost protection, the external box and associated cabling seemed an add on which wasn’t well thought through.
  • Make sure the control panel for the system is on the drawings and there’s a spec for the cable.

Installation lessons

  • Insulate the exhaust and inlet ducts through the wall with a short length of insulation at first fix. Carry out all sealing and air-tightness measures back to the external wall at this time.
  • Provide very robust temporary sealing to the duct ends post first fix.

I attended a training seminar organised by the Green Register and run by Fraunhofer IBP last week for a piece of software called WUFI Pro.

WUFI is great, if a bit specialist. It simulates the distribution of moisture and heat in a construction build up over time. If that’s not enough (and for some people that is probably more than enough) it can do this using hourly weather data and over periods of tens or hundreds of years. I know, amazing!

In the real world that means I can use the software to help predict if there will be a problem due to moisture inside a wall. This might be useful when planning to insulate or upgrade an existing wall in an old building (such as Insulating Bungaroosh walls in Brighton), checking a new type of roof build up, or for working out why there is a problem in a building. At its most basic it can predict interstitial condensation, getting more complicated it can show the variation in thermal performance as the construction dries out, show what happens if there is a fault in the building fabric, and even predict actual expected mould growth and type.

Probably too much information! It can also produce pretty animations like the one below lifted from the Fraunhofer website.

WUFI animation

 

It shows a section through a wall. The left hand side is the outside of the wall with water due to rain penetrating the brickwork, the right hand side is the lovely warm and dry inside.

I’m looking to use my new found skills and am planning on putting together some standard wall constructions for insulating walls, specifically in Brighton to start with. Contact me if you’re interested.