Window installation guide and Velux VFE

[GrantMcscott]

Hi

Does anyone know of a good guide on the correct way to install a window (mine are ali clad) into a timber frame house.  What flashing are needed ect and how to make sure it is water tight as they will be installed into the cavity barrier.

 

Also install some Velux VFE windows (the vertical ones) should they have cavity barriers around them and also how do I seal them as there is a 10 mm gap around them 

 

thanks

[Timedout]

We did this back in 2012. Our house had timber frame with brick outer skin. The recess left by the frame designer did not work out correctly and we had to improvise on site. Our joiner was a very resourceful chap and got it sorted. Our cavity closers were the mineral wool firestop type. The VFE projected slightly into the brick but being mounted to the frame and roof had to have movement allowance. We used Compriband expanding foam tape for various junctions but the final seal was usually low modulus silicone. The Compriband was certainly under the VFE. The VFE windows (we only used two) did have a flashing kit and if I recall there were lots of bits left over. We would have followed the Velux hieroglyphs very carefully. They often take a lot of thinking about.

 

My memory is unlikely to fully accurate and I don’t have access to any of my photos at the moment or indeed the next three months or more. I do recall going over the house about a year after finishing and re-sealing where some silicone has torn due to the differential movement. Thereafter it seemed fine. However, we sold the house in 2015 and moved hundreds of miles away. What I do know is that we never had any issues with water ingress at all anywhere in the house. So, whatever we did with the VFE and top hung roof windows attached to them worked as it ought to.

Compriband is great stuff but tricky to use. I don’t think there is really a suitable alternative though. Regular squirty foam definitely not. Flexifoam possibly but I do not know if it really has the range of movement the application demands.

 

[GrantMcscott]

1 hour ago, Timedout said:

We did this back in 2012. Our house had timber frame with brick outer skin. The recess left by the frame designer did not work out correctly and we had to improvise on site. Our joiner was a very resourceful chap and got it sorted. Our cavity closers were the mineral wool firestop type. The VFE projected slightly into the brick but being mounted to the frame and roof had to have movement allowance. We used Compriband expanding foam tape for various junctions but the final seal was usually low modulus silicone. The Compriband was certainly under the VFE. The VFE windows (we only used two) did have a flashing kit and if I recall there were lots of bits left over. We would have followed the Velux hieroglyphs very carefully. They often take a lot of thinking about.

 

My memory is unlikely to fully accurate and I don’t have access to any of my photos at the moment or indeed the next three months or more. I do recall going over the house about a year after finishing and re-sealing where some silicone has torn due to the differential movement. Thereafter it seemed fine. However, we sold the house in 2015 and moved hundreds of miles away. What I do know is that we never had any issues with water ingress at all anywhere in the house. So, whatever we did with the VFE and top hung roof windows attached to them worked as it ought to.

Compriband is great stuff but tricky to use. I don’t think there is really a suitable alternative though. Regular squirty foam definitely not. Flexifoam possibly but I do not know if it really has the range of movement the application demands.

 

Thanks for that ours are projecting quite a bit into the cavity maybe just touching the timber frame.

 

was not sure if firestops were put against windows that they needed to be sealed by something else.  It looks like screw fire stops to windows and screw to frame and put tray above nothing else needed