Which Sealent/Caulk around window (Internal)

[Bobbya82]

Hi,

Was wondering if someone could advise on which or what type of mastic I should be using around windows and window board internally. So far I have tried Dow Corning 781 Acetoxy Silicone Sealant http://www.screwfix.com/p/dow-corning-781-acetoxy-silicone-sealant-white-310ml/45959 which gave a good finish but seemed to leave a clear line on the painted plaster where I have cleaned it off and Geocel Painters Mate Flexible Acrylic Filler http://www.screwfix.com/p/geocel-painters-mate-flexible-acrylic-filler-white-310ml/35403 which left no marks but has cracked up in places.

Any advice would be really helpful?

Thanks.

 

[misterhelpful]

I always had trouble deciding which sealant was best to use for perimeter pointing upvc frames and was pointed to this link courtesy of crank39 a while back.

http://www.thewindowman.co.uk/sealants.htm

Since then I have used low modulus silicone and it has worked perfectly well with much greater flexibility.

The Dow Corning you are using is high modulus and more prone to problems. You could try their C60 which is low mod, and has worked well for me in the past, although I mostly tend to use whatever low mod is immediately available to me, as and when required, these days.

 

[Grenage]

Do folk not generally just use decorators caulk for internal trim? I only ask, as I'm about to do the very same.

 

[Bobbya82]

Thanks I will take a look, just to confirm these low modulus silicones are ok for use internally?

 

[Bobbya82]

Would this be ok then? http://www.screwfix.com/p/no-nonsense-builders-silicone-white-310ml/70356#

Thanks again

 

[misterhelpful]

The one from Screwfix might not be the best but I've never used it so can't say for certain. It does tick all the right boxes, and the reviews seem good, though. I have used some of their other No Nonsense products and found some to be fine while others are poor, so it's a bit hit and miss.

As for the query about caulk, yes, people do use it for frames but as the OP has found, in some instances it will crack. It all depends on the flexibility of the chosen product and the amount of movement in the frame but in a lot of circumstances it is perfectly fine, providing you use one with a high flexibility.

EDIT: Yes, they are fine internally, but can sometimes take a little longer to cure so try to avoid rubbing anything over it.

 

[Grenage]

Thanks a lot for the clarification.