raised ground or separate retaining wall?

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I am at the 'idle curiosity' phase of planning a large extension. Currently the ground rises about 1.5m from the end of the house to the boundary about 5m away. Would there be much difference in cost between excavating to a new retaining wall at the boundary (well over 6m from neighbouring structures) or having the elevated ground against the end wall of the house 1m from the boundary?

My guess is that a retaining wall would be expensive and not achieve much. The ground is chalk and probably over 30m above the water table, so subsidence or drainage shouldn't be a problem.
 
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One thing i would mention is depending on the area you will be very surprised at how much material you need to cart away and that may add significantly to the cost of taking the wall back to the boundary.

When you say ''having elevated ground against the end wall of the house''

I am not quite sure what you mean? A retaining wall near the house would be fine but if your keen to level the ground that rises to the boundary you may need to cart in some material. On the other hand if you were just planning to slope this area you will be surprised at how difficult it can be to 'do something' with a face like that if its anything more than a metre.
 
you will be surprised at how difficult it can be to 'do something' with a face like that


No need to get personal now is there! :LOL:


I too am confuddled as to what the hell he's going on about.
 
There is about 1m wide of ground at the high level. I could cart that away (about 12m³) and have a retaining wall at the boundary with a side path in the 'normal' place below the normal damp course. Alternatively, I could have the side path about 1.5m higher at the level of the neighbours' garden but over 1m above floor level. I assume that the house wall construction would be more complicated/expensive as the cavity cannot drain to outside.

The question is whether the extra complication of the house wall with ground level above floor level is worth it to avoid a separate retaining wall?
 
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Oh ok, i got the retaining wall at the boundary idea but misunderstood the other option. I would steer well clear of raising the ground level in contact with the house as it has a risk of giving you problems down the line.

Also if it touches the house BC will be interested and will may want to see SE calc's. The expense of tanking, building a secondary wall (as a normal 4inch outer leaf wouldn't be up to the job) and the slight risk factor of future problems would definately make me more keen on the boundary wall option.
 
Oh ok, i got the retaining wall at the boundary idea but misunderstood the other option. I would steer well clear of raising the ground level in contact with the house as it has a risk of giving you problems down the line.

Agree.

Bite the bullet and hire a digger.
 

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