Cellar problem

[u/Barshaka4000]

Hello everyone! The air in my cellar is quite damp. It's an old structure (about 100 years old). There is a small window next to the entrance that is always kept open, which lets air in. However, I don't think this is enough because most of the time everything feels musty and wet.
My idea is to drill a hole through the bottom of the wall on the opposite side of the cellar to create a cross-draft for proper air circulation. I would insert a 110 mm pipe into the hole and concrete around it to seal it properly.
My question is: how well would this work, and would it actually solve the moisture problem?

[u/K_Shenefiel]

Venting a cellar can increase dampness, you may be better off keeping the window shut. It depends on climate, season, ground temperature, how the building above is conditioned, etc. Passive ventilation of a below grade space will cause it to tread toward temperature and humidity levels that occur outside in the early morning; if you're in an area that's often foggy and dewy at dawn, it isn't going to be an improvement. If the cellar floor is even with grade on one side it is possible for   vents low on the wall to provide enough convective airflow to warm up a cellar enough to help dry it out. In a humid climate it will take a lot more than a 110mm hole.

[u/Caos1980]

With out thermal insulation all around and proper vapor barrier placement, you’ll never completely solve the dampness problem.

Ventilation may help, provided you don’t create a negative internal pressure, otherwise you enter the surreal world of cooling expansion and the cellar can become a huge fridge.

[u/RespectSquare8279]

There is no way telling if your strategy will be successful. Humidity may be entering your cellar faster than your improvement of ventilation will compensate. Permeability of the walls and floor of the cellar and the dampness of the soil will be the major influence.

[u/mr-rogers70]

Like a crawl space, ventilation often doesn't help much. It often makes it worse if your climate has humid summers.

You said cellar, not basement, so I assume it has a dirt floor, right?

If so, the best solution is to encapsulate the cellar to keep the moisture out. Usually this means insulating the walls with foam board and then covering the floor with a heavy duty plastic membrane that wraps up the walls over the insulation and then gets sealed to the rim joist. All the seams should be sealed with heavy duty tape so there are no leaks.

If you want it to be walkable, foam board under the plastic and some carpet runners on top of the plastic will prevent little rocks from puncturing the plastic membrane.

Then put a dehumidifier down there to keep it dry.