Having deeper cills on the inside, any issues?

[dedvendies]

Hi there, we're having a new extension.

I guess the standard thing is to have the thickness of the exterior wall and place the double glazed window in the middle.

We were thinking it would be good if the window was closer to be flush with the exterior wall so on the inside you have a deepr cill. The thinking being that we can put small basil plants etc.. in the window.

Is this weird, or will it cause any issues?

Thanks in advance.

 

[Gazman16]

Weathering and insulation issues with externally flush.
Ideally want to be at least 30mm back from external for weathrproofing but you BCO may want behind the external brick for cavity insulation.

Have a word with your builder and BCO

 

[phatboy]

Gazman, didn't you post a while back about issues when plastering across the cavity, which it sounds like would be required here?

 

[crank39]

New build so you can incorporate cavity closers so no issue plastering over the cavity, generally the inside face of the window should fall in line with the inner face of the external bricks, this would like gaz says give you the 30mm you need on the outside

 

[dedvendies]

Thank you for all the help.

Our architect has allowed 4 cm on the outside so this sounds good. He's made a lot of mistakes which has meant resubmitting a few times so I'm just double checking things

 

[Gazman16]

Gazman, didn't you post a while back about issues when plastering across the cavity, which it sounds like would be required here?

As Crank said. Generally new builds use pvc cavity closers so no issues. Brick returned cavity's could cause problems if the window does not go bast the vertical DPC though.