Fireplaces, Heating Stoves, Flues and Chimneys - Safe for wood to touch chimney?

Dumb question probably...but here goes.

I have a steam boiler fuled by oil. There is a concrete block chimney going up from the basement to the roof (one story ranch). There is a gap around the chimney where it passes through the floor and also when it passes through the ceiling. Since the attic is open to the outside (through vents) it also makes my basement effectivly open to the outside.

The basement gets very humid and I want to run a dehumidifyer down there, but obviously I can't dehumidify the world ...

Is it okay to close the gap with wood, or what should I use? I don't think the hot air going up the chimney is hot enough for the flash point of wood but I figure its best to ask and make sure.

Although many older homes were built tight against the chimney, wood should be held back, I believe it is, 2". To close your gap, use some metal flashing and seal it with fire rated foam caulk. It is important to seal both top and bottom. This gap is referred to as the chimney chase and has been costing you some $$ over the years. So, good idea, seal it up.

While you are at it and have some extra foam, locate and seal all vent pipes and electrical holes. Check any recessed lights, they should be air sealed and IC (insulation contact) rated. You can also find a substantial listing of "thermal bypasses" that the energy auditors look for when recommending efficiency upgrades.

You also mention excess humidity in the basement. In addition to the dehumidifier, try to locate the source of the moisture and correct the problem there. Any spaces with a dirt floor are noted as having excess moisture and should be covered with a vapor barrier.

Hope this helps
Bud