Painting flexible Filler

[TimSteer]

Hi Everyone,
I have a bit of a problem in that the ceiling of our bedroom, which is angled as it extends into the angle of the roof, had some largish cracks in it. As I thought there might be some movement there I decided to use some "Polycell Flexible Gap PolyFilla" which came in a blue tube that could be squeezed out. Now there was a slight step between the sides of one of the cracks I was filling so I applied a couple of applications of this filler and spread it out to even up the surface. I realised when I was applying it that it was very much like a silicone sealant and dried with quite a sheen to it and was quite rubbery.
So 24 hours on and this morning I have gone to paint over it...I've given it 2 coats of Dulux Magic White Matt (I had some left) but I can still see the sheen through the matt paint.
I am expecting to have to redo the whole ceiling again anyway but I need to deal with this sheen which is showing through the paint where I have applied this flexible gap filler.
I would appreciate any advice on this as there are 4 loactions on the ceiling that I have used this.
I am wondering whether I need to use some form of undercoat or whether I should just build up coats of the magic white and then when its covered give the whole ceiling a fresh coat of a better matt white?
Would really appreciate some advice.
Many thanks
Timmo

 

[joe-90]

If in doubt get the oil based undercoat out - it sorts nearly every type of coverage issue.

 

[TimSteer]

Thanks, so just cover the are I have filled with that and then when I put the white matt emulsion on top I won't be able to see any demarkation where the undercoat or filler was? I hope it is that simple.
Thanks for your advice
Tim

 

[joe-90]

Yes. Simples.

 

[TimSteer]

Thank you very much for that...I'll wait until tomorrow to make sure the emulsion is totally dry and then I'll slap on some undercoat..I'm sure I've got osme in the garage..Whats the recommended matt white emulsion to use for a nice bright white finish?
Thanks
Tim

 

[joe-90]

Most of the big names are pretty good. Dulux costs about the same as the rest these days. Glidden are good too.

 

[TimSteer]

Well is the Magic White renowned for not being that good..Where it has dried (and is not on top of the filler) it doesn't seem as bright as the rest of the white matt which a decorator used about 3 years ago..which is worrying..