Polyfiller and floorboards

[Monaco]

I am trying to insulate my house more and can feel cold air coming though these gaps where my wood floor meets the brick/doorway. Can I polyfiller this gap or do I need something else to fill it in?
Thank you

 

[Alec_t]

Something which blocks the air, is waterproof, and allows for expansion would be better. Strip of foam plastic?

 

[jacko555]

Not polyfilla, will crack.
Cheap and quick - grab a handful of loft insulation and stuff it in there.

There's professional stuff for this (compraband?) but expensive.

Or caulk/mastic gun the gaps. I did that under some skirtingboards to stop a breeze

 

[Monaco]

Thank you- will caulk not crack with expansion? I may go for this option

 

[Koolpc]

Flexible sealant may be a good option

 

[Deleted member 174758]

Silicone is a better alternative than caulk and won't crack, but neither can be guaranteed to span a gap of more than 6 or 7mm without slumping. For bigger gaps, stuff some closed cell foam into the gaps (e.g Fossa Caulk Saver) pushed a couple of millimetres below the surface, then finish with silicone. Silicone can be purchased in a variety if colours. Use a silicone finger to finish the surface off rather than a finger - much less messy!

There's professional stuff for this (compraband?) but expensive.

Compraband, a highly compressed closed cell rubber foam "tape" is what we use to seal around uneven floor edges (e.g. laminate flooring to original brick walls in mill conversions, etc). Brilliant stuff, expands to fill gaps from about 4mm to 30mm but I agree that it is rather expensive. But you do pay for speed, convenience and lack of mess