Draft under floor

Hi,
So I pulled up the carpets in my new-old house and saw some lovely pine floorboards. Hardly a mark on them at all. I thought I could save myself a few quid by just sanding and varnishing them.

The problem is that there's a gale blowing under the floor. On the front and the back of the house there are air vents below floor level.

I cant pull up the floor to put insulation in. Can I just close the vents outside the house. Surely with the chimney and various other holes there will be enough fresh air in the house?


Thanks!

the clue is where the vents are

if you block them off after around 5 years could be sooner or longer you floors will rot and collapse

I was afraid of that

I'm also afraid of spending the rest of my life holding a silicone gun hunting around the house for drafts while my wife complains of the cold!

I also have airbricks set just above the dpc which makes the underfloor space extremely cold when the wind blows.. In the winter I put a concrete paviour up against them then remove them in the spring.