Cedar cladding

[paul_round]

We have recently had a large two storey extension, clad with cedar, it was finished about 9 / 10 months ago.
Recently after some very heavy rain we noticed some damp on the inside above the window. In the attached photo you can also see some discolouration on the closing panel underneath the cladding.
My question is, should there be ventilation / drainage holes in this closing panel.

 

[freddiemercurystwin]

Yes there should be a gap for ventilation at the head and cill (and also at the bottom and top of the wall), this allows any moisture to vent out and any actual rainwater to drain out at the head of the window or bottom of the wall. Fundamental stuff with timber cladding, plenty of typical details on google eg:

Did the drawings not show there was ventilation/drainage to be provided?

 

[paul_round]

Thanks for that. None of that was on the drawings.
I have forwarded it to the builder.

 

[^woody^]

The detailing above and below the frame is wrong.

Above the opening there should be a screened ventilation slot, plus a drip to cast off rain water away from the window frame, and there should be a tray fitted the timber frame behind the cladding, to direct any water in the cavity out over the drip.

Below the cill there should be a screened ventilation slot and a flashing to direct any water from above the cill out off the cladding and prevent it entering the cavity.