Should i fill gaps between blocks and joists?

CCoomber · 2025-12-09T20:50:43+0000

Hi, I'm currently replacing my dining room ceiling and I noticed where the joists rest on the inner blockwork wall there are some pretty big gaps (see attached photos). Some are large enough to see the cavity insulation and the outer skin of brick.
Should I fill these in with some mortar? or is there a reason I should leave a gap around each joist for some ventilation?

Thanks in advance for the advice.

freddiemercurystwin · 2025-12-09T21:47:19+0000

Yes fill with some mortar or expanding foam.

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Should i fill gaps between blocks and joists?

CCoomber

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