Damp patches on carpet underlay

Boohoo

Eldi_Dos said:

I could see water tracking along that electric cable and in through the conduit.You want to see if you can get a bit of slack so you have a drip loop before cable enters conduit, then get a pug of some sort to seal the conduit.I would use putty myself if nothing else is to hand, just make sure it is well kneaded before use.

A bigger area of concern is the patio stonework going right up against wall, did the people who put in the airbricks not mention it to you?

Edit: you could take off those three cable clips and drop the cable so it is lower than the conduit an then reclip and seal conduit.

I think it's a bit cruel to use a dog(pug) to seal the conduit.

Water could also be getting on the wall when the OP waters the plants maybe.

twopenny

Both the paving can trap moisture and the roots of the climbing plant go into the ground right at the base of the wall.
Wrong corner for sure but that may mean there is soil against the bay window and to some depth.
That will hold moisture against the bricks 

Nubley

Yes I had been worried that the level of the patio might have been such that it was breaching the DPC but the surveyor from Timberwise dismissed that, thought the DPC was sound and said there was no evidence of penetrating damp in the wall.

twopenny

What was his technique for testing damp in the brickwork?

I must admit from the pattern of damp on the underlay it does look first like the radiator valve leaking. A little water can go a long way.
Try wrapping some paper towels around the pipe and check the next day.

With such a major case as having to replace joists I'd be inclined to chip a small area of plaster away just above the skirting, about the size of a 50p, and see if it's damp behind. Dab with toilet tissue, maybe leave a bit there overnight.
Refill with a small tub of ready mixed plaster and spatula.

I'd also lift the membrane that's under the gravel. That soil will be damp. 
Scrape some away about 4" and look to see if the bricks are damp.

Easy to do these and easy to put back.