Old drawings

[roythegrass]

In a previous post under ‘building’ I have raised various questions relating to foundations for a conservatory. Due to clay soil conditions and a nearby mature tree two separate structural engineering companies have advised me to have a hole dug as close as possible to the existing house foundations and take a soil sample for analysis which must be from at least 1m deep or at the depth of the existing house foundations whichever is the deepest. It is entirely possible that the existing foundations are 2.7 m deep and the practicality and safety of excavating a test trench to this depth is questionable to say the least.
To establish the existing foundation depth I approached the LA to see if they still had the drawings for the house – built in 1987- and they say they have no records pre-dating 1990. Is this normal for LAs not to archive plans over 27 years old ?
Roy
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[freddiemercurystwin]

Does it really matter? If they haven't got any they haven't got any have they?

 

[CambridgeBrummie]

The only reason to obtain a soil sample is in order to determine the potential shrinkability of the clay. If you don't want to do the sample then assume it has high shrikability (which is the general rule for most over consolidated clays). Depth of foundation will then be determined by the tree water demand, mature tree height and proximity of the tree to the foundations.

 

[JohnD]

round my way they take these samples by boring into the ground and/or bashing a hollow steel pipe into it to take a core.