Cavity closer question

[Tally101]

HI All
Im having new windows soon to replace our 25 year old ones thats got various problems. Question is when the guy's surveyed the windows they took some trims off to see if they had cavity closers which we haven't. Will the new windows be fitted with cavity closer or are they not required. The new window guy's make the windows in their factory.
Thanks

 

[Wayners]

Something will have to bridge cavity. I don't know when cavity closers where first used but are spec to new buildings.
They might just fit windows and fit plastic trim to cover gap.
You need to ask window company what the plan is, but I've seen loads that are just covered over with plastic which caused me trouble especially with plastic trim fitted over wallpaper that I'm removing