Trickle vents partly in extension

NeverTooLate

We're having an extension built along the back of the house. The existing kitchen wall will be removed to create a large kitchen/diner.

In the new part of the room (extension) there will be french doors with trickle vents. I am also replacing the 2 existing windows in the kitchen (down the side) with new.

I understand that building regs specify that trickle vents have to be installed in windows in new builds and extensions but not in replacement windows if there were none originally.

So do I have to have trickle vents in the replacement windows too? Are they classified as being part of the new extension somehow as it will be one room, or am I overthinking it?

Trying to save bits of money where I can and as they are aluminum windows it adds a bit to the cost.

Doozergirl

I don't fancy the argument with the building inspector because you saved a few quid. 

They are likely to treat the entire room as new.  

Trickle vents do good work, and you don't know exactly how the changes will have affected the airtightness of the room, so it's a no brainer to have them anyway, imho. 

NeverTooLate

Doozergirl said:

I don't fancy the argument with the building inspector because you saved a few quid. 

I agree, but this is mse, so trying to save a few quid is what we're about.

There will be loads of ventilation in the room, extractor fan, and trickle vents in the main windows (massive windows). The windows I'm talking about are only 570mm wide, 2 of them so I can't see that the vents will have much effect on the whole room.

I think I'll just ask the building inspector if he's happy without the vents before I order the windows.

Just wondered if anyone else had had the same situation.