How deep can a periscope airbrick go?

[Weetabix]

Hi - old damp stone cottage - built into slope - circa 1900 - no visible DPC - rotten kitchen floor and joists.
Low crawl space - approx 12 inches.
Surveyor thinks penetrating damp from outside levels is causing wet rot.

Outside level approx 2m higher than flloor at back of kitchen (built into road to can't excavate) sloping down along side of kitchen.

Airbricks in place, but at 2m high at back - are these workable?
Is it actually possible to ventilate this floor or should I pour a concrete one?

Thanks.

 

[tell80]

Insulated concrete floor tied into bubble sheet tanking on the walls and probably channels and a sump pump needed.Specialist tanking/sumping guy needed on site.

 

[^woody^]

If the rot is at the bearings then the surveyor is probably correct, and the problem is penetrating damp not humidity.

Has the surveyor specified a repair?

Btw, lack of adequate ventilation tends to lead to dry rot.

 

[Nige F]

Have a look at Newton waterproofing. for the "bubble sheet"