Filling in gaps on window sill

27 Apr 2014
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United Kingdom
I'm currently redecorating my living room and am just preparing to repaint the window sill. I removed the silicone that ran between the window sill and the double glazing window so I could sand the sill. The DG frame is uPVC. When it comes to refilling the gaps should I use silicone as previously used or could I use decorators caulk?

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Do you know if there would be any advantage to using silicone? Using decorators caulk would be my preference, but don't want to do it if silicone has advantages to using it.
If installing new windows in an already decorated opening, silicone is the neatest and cleanest option but, when repainting, I would choose caulk. As long as you paint the caulk the same as the windowsill then it will be fine but unpainted caulk gets grubby in no time.

Some silicones are more flexible than caulk and are supposedly mould resistant but, in my experience, even these don't always work.
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Caulk tends to shrink, or not expand when wood moves. Silicone is more flexible, in my experience. I used caulk round my skirting, and it has cracked, and I used caulk around the edges of a new ceiling I put up in my porch, and it has cracked too. Silicone was used by the builders when they replaced my window boards, but I removed it and put in new stuff as it was not the neatest job. Three years later and no cracks. Mould can be removed with dilute bleach.
Wouldn't that be down to using the wrong modulus filler? Surely a lower modulus wouldn't crack?
Thanks for all the replies. I'll go with the caulk, and if I have any problems I suppose I can always run a bead of silicone on top of the caulk.

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