CHIMNEY STACK nightmare. We have a situation where we wish to install a log burning stove, but our chimney stack downstairs is actually just a single skin thermalite box and doesn't contain anything other than a flue opening in the top right corner. It is apparently unsuitable as a functioning chimney. The rest of the stack is brick above. Has anyone had extensive chimney work/rebuilding done in the area who may recommend a competent and structurally aware building company for such a task? General builders don't seem to want to touch it.