Advice needed ref subfloor prep

i need to level this floor,, but I could do with a bit of advice reference a problem (see photo)..

Any help appreciated

 

NA the lot job done

 

does it have a working dpm ?

 

I'll put a hygro box on it Friday to get a good idea ref damp..
The rest of the job has been great as far as prep goes, hall (T shape), bathroom and kitchen all ply into existing floorboards..
The "outhouse" should be straight forward., but was concerned about how to overcome the timber covering pipes..

At my late (ish) stage of life I'm a novice floorer, but sad to say, anal in doing it right

All replies greatly appreciated

 

is there flex in the timber channel ? if so you need to fix any flex. Might be that you fix battens to sides. But need to know moisture readings first to advice which way to go.

 

Thanks Matt, the timber is solid.. I'll post a reading by Sat morning..

 

Reading is 76%

 

Karndean... Will order in a tub of DPM1c if that's the way forward..
Thanks for the reply