How we achieve air-tightness in window installations – Dukes Meadow, visit 2

Today marked our second visit to Dukes Meadow in Woodbridge, and a lot has changed since we made the first video for our YouTube channel at this remarkable project. (Click here to watch that video.)

During this visit, many of the windows were being installed, including the visually striking small “punched hole” windows. okoHaus team member Dan talks us through how airtightness is achieved using the Illbruck i3 system. He also explains the use of TP600 Compriband, FM330 expanding foam and ME508 airtight tape, all of which are used to create the internal seal.

Our host, okoHaus founder John Lewis, explains how and why airtightness testing is carried out at multiple stages throughout the build. Now that windows and doors are going in, John walks us through several key features, including side-hung windows, night vents, restrictors, and safety additions like Juliet balconies. These enable the use of full-height windows on the upper floor, making the most of the stunning Suffolk countryside views. John also explains the difference between a casement door and a side-hung window within the Velfac system.

Since we’re still mid-build, it’s a great opportunity to take a closer look at how aluminium pressings and flashings are integrated after the windows are installed. This ensures a flawless finish and uninterrupted sight lines. The project includes bespoke elements such as corner flashings and mitred detailing.

This episode also gives another glimpse of our SmartLift in action. John explains why we decided to purchase a SmartLift rather than hire one, and how it contributes to both efficiency and safety on site.

One of the goals of the okoHaus YouTube channel is to give you a behind-the-scenes view of modern sustainable building. In this video, we show how windows are packaged and palletised before shipping to site. We also reveal how pre-labelling ensures that each window is fitted into the correct opening. In earlier videos, we talked about the importance of preparation before installation. In this episode, you’ll see that preparation pay off. The newly installed doors now align perfectly with the polished concrete floors.

Alongside explaining why the client chose the Velfac system, we also take a look at some of the other sustainability features built into this project. We’ll be returning to the site for future updates, but it’s already clear we’re beginning to capture what it will feel like to live in this home: natural light, peace and quiet, and clean air.

Have you been inspired by this visit? If you're planning a project, please get in touch to see how we can help. And if you enjoyed the video, don’t forget to like and subscribe – it really does help.