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Insulation and rising damp

We have a wooden floored house approx 100 square metres. We have a rising damp issue that needs serious remediation and insulation. After the earthquakes it appears the ground water table has risen. Also the ground under the house has risen and there is now insufficient space to crawl much around underneath. What are our options if any? A poly sheet, a foamcrete, or does the floor need to come up?