Hi Roger and Zach,

Now I understand the terminolgy and yes firring or furring strip would be run vertically and might generally placed over a gap e.g. vertical plank siding or panel join and battens run horizontally.

Zach,

Your observations re the interection between cedar and tyvec are very important as are the typar comments. Since you effectively have a 2 layer system would it be possible to dispense with either Tyvec or Typar and just encourage free ventilation to dry out water ingress ?

I currently have a problem with water ingress into our 2 bay oak framed granary (about 1600). Check out a photo of the south west floor taken yesterday morning after experiencing heavy windblown rain.

http://www.kfhume.freeserve.co.uk/pictures/Granary%20Interior.jpg

and also check out the corresponding exterior view of the larch siding on the exterior corner.

http://www.kfhume.freeserve.co.uk/pictures/Granary%20Exterior.jpg

There is no liner paper and the boards are attached by nails direct to the oak frame infill studs. Clearly this problem has been at work for quite a while (100 years +) since a previous attempt has been made to cut out and replace some of the interior elm plank lining planks which in turn have themselves had rat holes knawed through (to help improve ventilation of the void space - nice work rats !).

I suppose that I might need to tear off the lower sideing on this 400 year old historic building in order to try and identify the source of this water but the problem then remains as to how best to prevent water ingress or alternatively should we continue to allow sporadic events like this and then simply ensure that sufficient ventilation is present to quickly dry out the water.

Your thoughts would be much appreciated.

Regards

Ken Hume