AI summary of my soil test plasticity report.

Put my soil plasticity test results into AI. I don't know if it's right or wrong but it seemed good news to me. You could tell the soil near the trees was very gravely when we dug it. I was expecting around 2m depth along this wall so to find out it's going to be a lot closer to 1m is great news. I have to send all the details over to the engineer once the layout is confirmed. Hopefully the AI is accurate and he comes to similar findings.

Hi [Name],

Please find below a summary of the soil laboratory test results ( Report xxx), the BS 5837 Tree Survey (xxx), and site drainage investigations for the proposed new dwelling (approx. 11 m × 8 m footprint) at the rear of xxx:

1. Soil Classification & Shrinkability (Atterberg Limits)

• Hole A (1.00 m – North-West / Trees): Yellowish brown sandy CLAY with abundant gravel. Liquid Limit (LL) = 42%, Plastic Limit (PL) = 15%, Plasticity Index (PI) = 27%. With 47% passing the 425µm sieve, the Modified PI is 12.7% (Low volume change potential).

• Hole A (1.50 m – North-West / Trees): Orangish brown sandy CLAY with abundant gravel. LL = 42%, PL = 15%, PI = 27%. With 41% passing the 425µm sieve, the Modified PI is 11.1% (Low volume change potential).

• Hole B (1.00 m – South-West / Control): Greyish brown mottled grey CLAY with rare gravel. LL = 40%, PL = 12%, PI = 28%. With 99% passing the 425µm sieve, the Modified PI is 27.7% (Medium volume change potential).

2. Moisture Content & Desiccation Check

• No Soil Desiccation Recorded: Comparing the Equivalent Water Content (<425µm) against the Plastic Limit confirms the clay is not desiccated:

• Hole A (1.00 m): Equivalent Water Content = 21.4% vs. PL of 15% (Liquidity Index = 0.24).

• Hole A (1.50 m): Equivalent Water Content = 40.5% vs. PL of 15% (Liquidity Index = 0.94 – note: soft/wet matrix at 1.50 m).

• Hole B (1.00 m): Equivalent Water Content = 15.1% vs. PL of 12% (Liquidity Index = 0.11).

• Because the clay at 1.00 m is already at normal moisture levels with no desiccation profile, there is no significant risk of ground heave from removed vegetation.

3. Arboricultural Context (xxx)

• Removed Apple Trees (T003–T007): Confirmed in the survey as regularly pruned garden fruit trees (2.5 m – 5.0 m height; max stem diameter 430 mm). All have been felled and stumps completely grubbed out by excavator, eliminating any future regrowth or water extraction.

• Removed Conifer Hedge (T012 – South/Control Zone): Confirmed in the survey as a young, trimmed ornamental Cypress group only 1.0 m high, located ~6.0 m – 6.5 m from the proposed foundations, and now removed (well outside its 1.25 m zone of influence).

• Retained Boundary Hedge (T008 – North): Confirmed as a clipped 1.5 m high Holly and Privet hedge (Low water demand; 0.75 m zone of influence – no impact on foundations).

• Retained Apple Tree (T002 – North): Recorded in the survey as a regularly pruned fruit tree at 6.0 m height (currently trimmed to ~4.0 m) with a 4.7 m RPA radius, located approx. 3.0 m – 4.0 m from the northern foundation wall. (Note: T001 is a 4.0 m regularly pruned Pear tree to the east with a 3.6 m RPA).

4. Drainage & Warranty Context

• Existing Combined Sewer: Trial excavation has confirmed the existing combined drainage run sits outside the proposed house footprint, so no sewer bridging or Build-Over Agreement is required.

• Removed Rubble Soakaway: A small rubble soakaway serving the existing garage was located inside the proposed footprint. This has been disconnected, excavated, and removed (with garage surface water to be redirected clear of the new dwelling).

• Warranty Status: Not proceeding with an NHBC warranty; designing to Building Regulations Approved Document A.

5. Proposed Foundation Approach for Review

• Northern Wall (Adjacent to Retained T002 at 3.0 m – 4.0 m): 1.15 m – 1.25 m depth on Low shrinkability clay (Hole A), accounting for T002's 6.0 m regularly pruned height, lab-proven absence of desiccation, and xxx regional climate. Any excavation clipping the outer edge of T002's 4.7 m RPA will be carefully root-pruned in line with BS 5837.

• Remaining Perimeter Walls (Holes A & B): 1.00 m general trench depth across Low and Medium shrinkability zones.

• Localised Deepening (Stump & Soakaway Pits): Any foundation trenches crossing the excavated apple stump holes or the removed soakaway pit will be taken locally deeper through any disturbed soil down to firm, undisturbed natural clay (and backfilled with compacted granular fill where inside the floor void if required).

• Ground Floor: Standard suspended floor construction (e.g., beam-and-block with 150 mm void).

Please let me know if you need the full PDF reports to finalise the foundation drawings.

Kind regards,

[Your Name]

Edited just now1 min by Oz07