Ideal ground level

[mh12]

I've finally realised that high or sub-optimal external ground level seems to be a culprit and easy to fix source of internal damp issue.

Therefore, ideally how many cm below internal finished floor level should the external ground be in in-order to avoid and rising damp/internal damp issues from external grounds? i.e. is there a minimum threshold?

Thank you

 

[Cubist]

A very crude guide would be circa 200-250mm below the bottom edge of any air-bricks in hoes with suspended wooden floors OR 300mm for solid floors. BUT, no lower than two brick courses above the footings/foundations of the walls.

 

[mh12]

Have been doing some digging yesterday, Victorians built their properties properly. found I think it was about 10 layers of 76mm foundation bricks beneath ground level.

Currently 3 old blues (80mm showing above ground level) adjacent to wall perimeters.

I think I might need to lower the grounds around wall perimeter , thinking French drain , OR lower the whole of slabbed garden level, approx 30m2 by about 30mm to reach the required 300m you've suggested. There is some damp in the kitchen area solid wall construction and gypsum plastered.

However house has been unoccupied and unheated for a few years with locked doors, windows so poorly ventilated as well, currently undergoing renovations.

Im think cause of damp perhaps might be leaky guttering.

 

[stuart45]

When it's hammering down, go outside and check your gutters. Also a good time to get up into the roof space and check for any leaks.