I had ridge venting installed when I had my roof redone on my bungelow. Now the gutters are of need of replacement and one contractor is recommending installing a gutter shield. To me, it looks like the gutter shield will block the air flow for my ridge venting. The contractor said the air flow will be the same as air will go under the gutter guard into the gutter and then up into the ridge venting. Is the contractor correct or will installing this large gutter shield reduce my venting?