Hi Catherine, the glass panes in a louvre window overlap to ensure an effective seal against wind and water. We sell thousands of louvre windows each year and sealing of blades has never been an issue. However, you should always check that the manufacturer you go with and products you select comply with industry standard AS2047:2014. Products must comply to this Australian standard for wind and water penetration and are independently tested, before they can be certified compliant. All A&L products are certified compliant with this standard.

I you are changing from stacker to bi fold doors you should ensure that there is a single door included within one of the bi folds, preferably next to the kitchen. I wonder why you are deciding between white or black windows and doors for this room when you already have white elsewhere. What colour are the internal and external walls.

Flip up and bi-fold are indeed "all or nothing" options that can be tricky to screen too. Both also rely heavily on well-engineered operating mechanisms and as such come with increased potential for problems. I once stayed in a house on North Stradbroke Island which had a large flip up gas strut supported timber framed window over the north facing kitchen sink with views to Cape Moreton. (I now wish I had a photo to share, but sadly I was too much in the moment to take any.) Standing at the sink, looking north over the Coral Sea with Humpback whales breaching in the distance was one of those forever moments. Plus, our elevated situation seemed to reduce the number of insects that came through the unscreenable window. In that case I wouldn't have compromised on spending to get that window out of the way. For just about every other context I would opt for a less complex, less costly, screenable, servery style window.

Bifold windows have been installed in our new kitchen servery opening to the outside pergola as shown in the first picture. The windows are from Trend Windows. The gap at bottom ranges from 4mm to 6mm. There is an obvious concern of weather and insect ingress through the gap. The renovation contractor has stated that Trend offer no sealing solution in this application and was intending to leave it unsealed. There is a channel in the frame under the window as shown in the second picture. The contractor states this is not suitable for a seal installed in the channel (such as from Dooorseals.com) because of the metal plates at the end of each window panel. That is, there would be a gap in the seal at the end of each panel. The contractor’s recommendation is to use a stick on brush type seal adhered to the outer side of the channel and also covering the end plates. Is my contractor right? Has anyone encountered this problem before and can recommend a product that would best suit the purpose. Many thanks.