What to do (if anything) with the gap between wall and flooring

Just moved house and had to remove some baseboards in the new house that had a mouldy look to them and found these rather substantial gaps behind them. The gaps are about one inch deep and 2-3 inches tall. I wonder if they were the reason for the mould, perhaps moisture was getting trapped behind the baseboards (eg after washing floors) with all that space being an ideal place for a damp environment. There are no other indications - like a leak - of anything else that would have cause the baseboards to go mouldy. What should I do with these gaps before attaching new baseboards? Fill them with foam ? Should I fill them? Or is the gap normal? Thank you

May 16, 2025 - 23:02

What to do (if anything) with the gap between wall and flooring

Just moved house and had to remove some baseboards in the new house that had a mouldy look to them and found these rather substantial gaps behind them. The gaps are about one inch deep and 2-3 inches tall. I wonder if they were the reason for the mould, perhaps moisture was getting trapped behind the baseboards (eg after washing floors) with all that space being an ideal place for a damp environment. There are no other indications - like a leak - of anything else that would have cause the baseboards to go mouldy.

What should I do with these gaps before attaching new baseboards? Fill them with foam ? Should I fill them? Or is the gap normal? Thank you