What sealant? UPVC window frame

[Miljah]

In our conservatory. These seams have opened up over time.

What white sealant should I use to fill them?

Ta.

white silicone. Mould-resistant if you can find it. Ther thinnest possible bead. Scrub out the gaps first (it will not stick to dirt) and do it on a cold, dry, sunless day when the plastic will have contracted.

look for a Fugi set of tools for shaping the sealant. Clean off any smears before they set.

Thanks!

Can I ask what solvent I need to clean up the black sticky gunge that collects in the corners of the glass units? White spirit didn't touch it!

that will be black mildew. you don't want a solvent. WUL, warm water and a soft paintbrush will clean it out.

To brush away the mildew, mix up a stronger solution in a mug.

Or, if you use car shampoo, you can wash down the frames as well and it will put a bit of shine on the PVC after rinsing off.

There is a product callled "Wet & Forget" that kills moss and mildew, it's easier to clean away once it's dead. I believe the chemical is poisonous until it's dried so you might not want it round the house.

Thanks- sadly it's not mildew! It's like congealed fat, jelly like and smears like glue!

I wonder if it could be silicone grease from assembly? It's translucent but might be mixed with dirt. WUL should shift it.

There is a special solvent for silicone grease but I think it's come off my hands with washing and wiping on a rag.

Yes, it probably is silicon grease, thanks!