Hi,
We live in a house that's half 1920's and half 2008. The old part of the house is great, no major issues, the new part has a fibre filled cavity wall with rendered concrete block outer and aerated concrete block inner. The house his fairly exposed at the top of a hill and it gets pretty damn windy.
2 upstairs rooms on the new end of the house are colder than the rest, even the downstairs room is a little colder but more manageable. It's certainly not loft insulation as there's 400mm up there. I had to drill a hole through the wall recently and as soon as I reached the cavity I could feel a fairly significant breaze coming through. I lifted a corner of carpet and put a hole through there too and I can feel the breeze under the floor too.
Is it normal to have that much airflow in a cavity and/or under the floor? If not any suggestions on how to find the cause and fix it?
Take a guess which rooms are at the new end.