Old house footings and ground level

[Kaymo]

Hi,
I've been dealing with dampness issues on an old house. I believe I have found the main source of the problem which was a leaking pipe at the base of the downpipe that comes down into the corner in the pic (removed at time of photo).

I also suspect that the ground levels have been raised and I want to ensure before I finish up here I get them back to the right levels. I'm hoping that there might be someone out there that has some experience with this, because I am not sure how I would identify where the original level should be. This is further complicated by my belief that the porch on the right was added in around 1885, while the original house I think is at least 1820. I suspect due to a few clues in the house that the floors were lowered in 1885 to suit the fashion of high ceilings when the porch and a Victorian bay window were added. In digging down I found what is like a sandstone plinth that my gut tells me should be above ground, but I am fairly clueless about this and there doesn't seem to be very much information online about what footings should look like. I suppose where I am coming from is that I the cut sandstone seems too good to be underground, as they seem to have normally only used cut stone back then in places where it would be seen.

Any help or suggestions much appreciated.

https://www.dropbox.com/s/flq58gvotntwwrr/2018-11-04 15.15.57.jpg?dl=0

Thanks.

 

[blup]

It may be that the "plinth" was constructed of whatever convenient stone was to hand.

You may be lucky and find that the damp is localised to the area of the down pipe leak but you will need to take up the floorboards inside to check this.

Blup

 

[Kaymo]

It may be that the "plinth" was constructed of whatever convenient stone was to hand.

This is the difficulty, it could be that the plinth is actually the footings and its meant to be underground, but I don't have a clue how to judge this. The fact that the vent was nearly at ground level is a sign that the ground levels were too high, but how low to take it down is the difficult part.

you will need to take up the floorboards inside

This is part of the plan. I believe the solum has been blocked by debris and is not ventilating and that is another contributing factor, but I want to finish up outside and ensure that part is sorted before I move to checking joists etc.

 

[blup]

Be aware too of the use of modern plasters and renders which might inhibit the building from "breathing"

There appears to be a step on the right of the photo which might be bridging damp through to the floor.

Blup

 

[Kaymo]

Thanks Blub, i'm aware of breathability issues and will be looking at this. My first priority is to resolve any ground water issues from leaking gutters and pipes (which I have done), then ensure the ground level and slope away from the house is right, before I start to deal with the issues internally.