Running a games table in a basement or garage
Three nerds who talk about gaming as literature have strong opinions about where you play it. The ideal is a dedicated room with a table nobody has to clear. For most people that means the basement, the garage or the room over it, and those spaces have a failure mode that has nothing to do with dice.
Four hours in a room tells you things an hour does not
A short visit to a cellar tells you very little. Four hours sitting still in one, twice a month, tells you everything. Players notice the cold at ankle height first, then the smell, then the fact that the character sheets have gone soft at the edges by the end of the night.
That earthy cellar smell is not atmosphere. It is airborne spores from something growing where you cannot see it, and the reason it registers after an hour rather than on the stairs is that your nose stops reporting it while the source keeps producing it.
Separate the two causes before you spend anything
Condensation shows up on the cold surfaces, spread fairly evenly, worst in winter, and it eases when air moves through the room.
Water coming in from outside is concentrated. A dark patch on one wall, a line low down that returns after it dries, a corner that is always worse. Ventilation does not touch it, and a dehumidifier runs forever without winning. Groups whose games room turned out to be in that second category have been sent to firms handling flood damage specialists in Buffalo and similar outfits nearer to them, because the question is where the water enters, and that is a survey rather than a gadget.
What this does to the things on the table
Paper and card are the first casualties, which in this hobby is most of the kit. Rulebooks swell along the spine. Card stock delaminates at the corners. Printed character sheets in a folder at floor level go wavy within a season.
Minis fare better, though the primer lifts off resin in a persistently damp room and a painted figure left on a shelf against a cold external wall will bloom.
Dice are fine. Dice are always fine.
Make the room usable while it is being sorted
Move everything off the floor and away from the external wall, even by a few inches. Keep the collection upstairs and bring down only what a session needs. Put a cheap hygrometer on the table and look at it in the second hour rather than the first, which is when the room has had time to show itself with four people breathing in it.
If a session leaves anyone with a headache or a cough that clears when they go home, stop using the room until someone has looked at it properly. That is not fussiness. The whole appeal of a basement table is that you can leave the game set up, and a room that is quietly rotting is one you should not be leaving anything in at all.
The good news
A sound basement is genuinely the best games space there is: no daylight on the screens, no neighbours, and a table nobody needs for dinner. Sorting out the water first is what buys you the fifteen years of campaigns afterwards.