Im looking at changing my gas fire back to a coal/log fire. Ive read about a lining being needed for one or the other but not sure which. With it originally being a coal fire then being changed to a gas fire would i need to have the lining removed or would it be fine to just put in a new hearth and use coal/wood (after having it swept) or is there more to it? The house was built around 1990 if it makes a difference.