Saving your home and your trees: new research on Geobear clay treatment impact on trees
Finding out your home is suffering from foundation subsidence is stressful enough. But for many homeowners, the traditional solution—which often involves chopping down or heavily pruning beloved mature trees—is just as heartbreaking.
Geopolymer soil injection has become a popular, less disruptive alternative to traditional underpinning. But a big question has always lingered for garden lovers: Does injecting this resin into the ground actually harm the nearby tree roots?
A recent multi-site case study across London and the East of England set out to answer exactly that. Researchers monitored the health of trees at several residential properties before and after geopolymer treatment to see how they reacted.
A "blood test" for your trees
To get highly accurate results, the researchers didn’t just look at the leaves. They used an advanced diagnostic tool called Arborcheck.
Think of it like a health screening or a blood test for plants. Arborcheck measures the tree's chlorophyll content and how efficiently it processes light (known as chlorophyll fluorescence). This scientific "vitality test" allows experts to detect hidden, underlying stress in a tree's system long before its leaves actually start turning brown or falling off.
The trees were tested before the geopolymer injection to establish a baseline, and then rigorously monitored again one and two years after the foundation repair.
The results: great news for your garden
The findings are incredibly reassuring for homeowners. Across the test sites, the vast majority of trees exhibited stable or even improving health following the geopolymer soil injections.
While a small number of trees did show a decline, researchers found that these specific cases were strongly linked to outside factors—such as pre-existing diseases (like ash dieback), overly aggressive pruning, or separate construction work happening nearby. Ultimately, the study found no evidence of widespread or substantial harm caused by the geopolymer treatment itself.
The takeaway
If your home is sinking due to clay-shrinkage and thirsty tree roots, you don't necessarily have to choose between saving your house and keeping your garden. This practice-based evidence suggests that geopolymer injection can successfully mitigate clay shrinkage below your foundation while allowing your beautiful, mature trees to safely remain right where they are.
