Old wood loft smell

[sealed]

1930s semi. Roof underboarded. No felt. No soffit vents.

I put a PIV in the loft. I read that there might be a stale air smell for a week but it has lasted longer.

so a roofer added two vent tiles to the front and two to the back to increase ventilation. There’s also a small window open in the loft.

It still smells stale. Do I just need to increase ventilation? More vents?

or is this type of loft always going to smell musty?

 

[Wayners]

Maybe treat wood with clear primer preserver