insulation/filler for gaps in window frames

For the outside Aluminium angles are standard. Inside you can fill with expandable foam for larger gaps. Smaller gaps say 10mm and under you can use sikaflex

great thanks i will try foam backing road for smaller gaps as DIY
will the have bigger in size for bigger gaps?

This is a really good example of one of the many differences between the building methods employed by a project home builder and a custom home builder, and why you pay a bit more for a custom built home.

With the windows, a project home builder will order pre-made or pre-fabricated frames and windows sort of sized to to those frames.

The issue is that that the it is nearly impossible to get your brick courses to match the window sizes and therefore you get left with large gaps around the windows. The standard fix for this is aluminium angles on the outside and gyprock on the inside. This will happen on nearly every window.

Having such large gaps is not great for the thermal performance of the home and in the long term there is also the possibility of bugs entering the home.

A custom builder will build the openings first, then the window manufacturer comes to site, measures and custom builds the windows for a much tighter fit. If there are gaps they will be filled both inside and outside with silicone and or an expandable foam.

Occasionally there is a need for aluminium angles to some windows, but this is generally more an aesthetic thing rather than a primary defence against the elements.

One of the things I have learnt building flame zone houses is the attention to detail, thought and planning that goes into building a really high quality home, and whilst customers pay more to have a home that complies with the FZ code, they end up with a super high quality build.

We basically can't have any holes or gaps in any part of the structure or roof with the exception of one stink pipe. So we really need to put a a lot of thought and care into how we run all of our services and cables, and where we do need to run some services through a wall, we have to use fire rated silicone and foam to ensure nothing gets in and out.

In addition, the roofs have 15mm of structural ply with every joint fire siliconed, eaves have 3 layers of sheeting rather than 1, window glass is thicker and the list goes on.

So basically, you end up with a home that is built to an extremely high standard. A lot of these techniques can easily be employed in building a non flame zone home without breaking the bank.

yes that window needs a header, good pick up