Dig trench lower or leave

Sekekama

1935 semi-detached Yorkshire. I had raised ground levels and obstructed air bricks which caused damp (image 1). 

Created a trench but I now found an old brick below new one (image 4) I dug down to get all air bricks to at least ground level. I've removed big stones to just have soil. 

There's 2 drainage gulleys for my house along this trench which I had found voids underneath but I filled with spare soil. I hosed water into the trench and eventually water soaks into ground but it does collect just below the old air bricks for awhile (image 4/2).

I've tried to remove as much of the concrete as possible off the face of the now exposed bricks (I will continue doing this before filling trench with pea gravel). 

Before winter I'm considering sealing the old air bricks (image 4) and half of the other one (image 2) in case of winter heavy rain because surely there's enough ventilation now? 

When I dug down deeper I just found clay soils and bricks and voids near the drainage gully, so I got worried as last thing want to do is disturb foundations. The inner subfloor is roughly 20 inches deep.

Also some of the air bricks are above DPC and some level/below. 

Dustyevsky

What is your question and why is this post in 'Gardening?' It should really be in the 'In my Home' (DIY) section, so maybe a moderator could move it for you.

As a previous owner of an old semi-dee, I'd not want to block up any subfloor air vents, especially if in a high radon gas area. I'd also want the ground level 150mm below the DPC, except perhaps in a sheltered spot where rain splash might not be an issue.

FreeBear

Dustyevsky said:

What is your question and why is this post in 'Gardening?' It should really be in the 'In my Home' (DIY) section, so maybe a moderator could move it for you.

Same question asked over on the house buying/selling/rental section.

https://forums.moneysavingexpert.com/discussion/6601595/should-i-lower-trench-or-leave