Add insulation to joists over plinth foundation

[JF.]

Hi!

I'm planning to add extra insulation to my floor, which is over an open pillar foundation. I find the floor gets cold in the autumn/winter. I crawled underneath to check and saw that there are some gaps here and there in the subfloor, which lets the wind blow into the joists. The question is whether a wind barrier is needed to protect against the wind, or if it's enough to just carefully add extra insulation?

 

[saltet]

We did the opposite. Tore up the floor and built new insulation because we only had sawdust as insulation. Also took the opportunity to reinforce the joists.
House on a pillar foundation.

 

[JF.]

We did the opposite. Tore up the floor and built new insulation since we only had sawdust as insulation. Also took the chance to reinforce the joists.
House on stilt foundation.

not an option to tear everything apart. Will be insulating from underneath.

 

[epw]

Put on a windbreaker and a facade board on the outside.