Splashback is eroding cob wall
- Thread starter ax222s
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- 21 Oct 2026
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Fixing the cause matters as much as the repair. If that roof is throwing water onto the base of the wall, a gutter or a downpipe to catch it (or a gravel strip / drain at the foot so it doesn't bounce back) will stop it happening again.
For the wall itself, cob needs to breathe, so avoid cement-rich render or any hard patch. A renderer who's used to cob would normally cut back the eroded area to sound material, then rebuild with a lime-based mix, and a lime plinth or a bit of stone/brick upstand at the bottom helps against splashback. Hard cement on cob traps moisture and tends to fail or damage the cob behind it, so ask any renderer what they'd use before you agree a price.
It's a straightforward job for someone who knows cob and lime, but not one for a general cement renderer.
For the wall itself, cob needs to breathe, so avoid cement-rich render or any hard patch. A renderer who's used to cob would normally cut back the eroded area to sound material, then rebuild with a lime-based mix, and a lime plinth or a bit of stone/brick upstand at the bottom helps against splashback. Hard cement on cob traps moisture and tends to fail or damage the cob behind it, so ask any renderer what they'd use before you agree a price.
It's a straightforward job for someone who knows cob and lime, but not one for a general cement renderer.
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