Damp patch under floor

[G1nzo]

Your advice would appreciated with this

Had a damp patch about 15 inches on the carpet
I have attached some photos
Lifted the carpet its being changed anyway
Turns out its right at the point where the extension was built and whats damp is the exterior brick course that was left there
There is some plastic sheet and torn dpc
The soil was damp around the area but the joists and everything else is dry
Whats the best action here
I was planning to clear all the damp soil out and put down membrane and cover the area in stone chippings
Any ideas gents

 

[Mr diy a lot.]

It’s a suspended timber floor spanning across the old external wall into the extension. If the joists are not damp then damp patch on your chipboard is completely unconnected to the damp you feel from the soil area. You sure there is any correlation at all?

 

[G1nzo]

Thanks for the reply
The block and external bricks that were there before the extension are still there it was the soil and bricks that were damp
There was a row of outside bricks left loose it was these that were damp as well as damp soil
The chipboard floor had a round hole in it about 30mm diameter this was under the damp patch on the carpet
Should Ieave the bricks there and cover with a membrane or leave it open to the air
The joists are not damp at all

 

[Mr diy a lot.]

The damp maybe moisture in the air condensing at the mystery 30mm hole where your warm house air was meeting you colder air under floor or something. Anyways - you don’t have a problem here. No membranes required in my view it won’t do anything. Insulate the space between the joints and install new piece of chipboard (without hole!) and you are all good I reackons.

 

[G1nzo]

Sir
Thank you
Will start tomorrow