Howdie folks.. bit of a newb question here..

When selling a property, is the seller obligated to disclose any repairs that were done by the properties previous owners, or is the current owners obligation only to disclose issues or repairs that occurred since they assumed ownership of the property? For example, if the prior owners had hired a specialty contractor to install some piers to the foundation in response to some settlement issues that they observed during the time they lived in the house, am I obligated to disclose the work that they had done to the foundation slab, since its an issue that was resolved prior to me owning the property?