Basement flat damp

[Furnace]

My daughter's London basement flat has a damp issue. She's had a 'damp specialist' report that proposes various remedies including chemical damp proof in places and tanking slurry in others.
In addition, the patio door cill and base of the stiles have rotted as the cill is at exterior FFL.

 

   

Do the experts think the patio door issue could be resolved by installing a threshold drain directly adjacent to the cill and bedding the new door on a dpm and sealant?

Or does the exterior concrete (about 15sqm) need to be lowered to achieve the typical 'all thresholds are 2 brick courses above exterior FFL'
TIA

Mark

        

Edited Thursday at 16:26 by Furnace
Resize images

[ToughButterCup]

3 minutes ago, Furnace said:

...
Do the experts think

...

 

The one thing we are not is expert.  We encourage everyone to do their own Due Diligence.

 

It would  seem from the images that the (lack of ) difference in height between the Inspection Chamber (IC) cover and FFL has a lot to do with the problem. It looks certain that that design is guaranteed to cause problems

[Redbeard]

Ideally the latter but the former might help. Also be aware that some interventions may cover rather than cure.

Edited Thursday at 16:31 by Redbeard
'would' to 'might'

[Furnace]

1 minute ago, Redbeard said:

Ideally the latter but the former would help. Also be aware that some interventions may cover rather than cure.

Indeed. I'm sceptical of damp stuff. I understand it can often be due to poor guttering/leaking pipes rather than 'rising damp' so that has been the first area for inspection. Water in the ground has to go somewhere, so stopping it in one place can often force it to another. Then there's the whole breathability issue.

I certainly didn't encourage her when a basement garden flat was on her wish list....

 

7 minutes ago, ToughButterCup said:

 

The one thing we are not is expert.  We encourage everyone to do their own Due Diligence.

 

It would  seem from the images that the (lack of ) difference in height between the Inspection Chamber (IC) cover and FFL has a lot to do with the problem. It looks certain that that design is guaranteed to cause problems

 

Not the sort of guarantee she was after...