Ceiling paint looks chalky & patchy

I painted 2 ceilings first the bathroom which came out perfect, the second the lounge room but for some reason the lounge came out chalky in one area where the light comes in the window. I used Taubmans easy coat for both rooms and a decent brand roller. I have done 4 coats now in the lounge thinking it would get better but it's still the same. The paint in the lounge prior to painting had no defects. Anyone know why this has happened and how to fix?

When you say chalky, does chalk come off on your hand when you rub it?

No nothing comes onto my hand just looks chalky and patchy. Thanks

I used to do paint inspections for a living but this has me stumped a bit.
Does the surface feel rougher than the other areas?

Yes it does feel rougher but the paint previously before I painted was perfect. After talking to my local hardware store they reckon this has happened because I had the heater on whilst painting hence the paint drying to quickly. If you look at the picture that patchy area is next to the heater vent. I am not convinced but I am going to give it another coat without the heater on and see what happens.

That's a high possibility. Give the rougher area a good sand first.
Never a good idea to paint ceilings with heaters on or even air conditioners in the sumner.
Hope all goes well

Forgot to ask. What roller sleeve are you using?

I don't know the brand but was told by my hardware store that the one I am using is one of the best. It's not lambs wool but does feel fluffy. I don't believe it's the roller as the other room I did which doesn't have a heater vent in it came out perfect.
Will give it a light sand on the weekend and paint over the patchy part with the same paint and same roller. If that doesn't work then I am going to change paint and roller and paint the whole ceiling again with no heater on. I am from Australia it's winter here and freezing in the mornings about 1 degrees hence why I had the heater on.

Im going to go out on a limb here, and hopefully this is not the case....
but are you sure you dont have this problem everywhere but just can't see it unless there is a window behind it shining light on it?
I can see a distinctive roller pattern there, indicative of either
not enough paint on the roller,
poor quality roller tray used, (needs nice deep ripples on the tray part)
trying to spread the paint to far (nto being generous enough)

You are probably right as you can only see the patchy part near the window. But why did the other room come out perfect same paint same tray same roller same rolling pattern. only difference no heater vent.
When I did the 3rd and 4th coats I put heaps of paint on the roller to try to cover it up but made no difference.

well that patchiness is evident and consistent with a roller pattern.
so the problem is not in the substrate, so rule that out and not due to heating, so rule that out as well.

please do not take offence, but this is typically seen when a roller is rushed across the surface.
The different sheen levels are most often the result of overworking the paint.
different areas of the paint are thicker than others, and the thicker parts dry slower than the thinner parts. so when you run your roller over it to remove the roller lines, it picks up up tacked thin parts and gives them a rough texture.
Go back and try it again with a 12mm nap synthetic/lambswool blend 230 mm (not 270) and do it very slowly in no more than 2 passes. one pass of the roller to apply the paint, and one pass to level it out.
one roller application should cover 2 lineal metres by one roller width, then reload roller.
give that a shot in that area and see if you can get a uniform texture.

Ok so I had another go. Gave it a lite sand Changed paint changed roller tray changed paint changed my rolling pattern as advised by rebuilder86 turned off heater and.......exactly the same the patchiness remains.

I then tried another room my outdoor patio ceiling came out perfect no lines patches or anything.

I am convinced there is something wrong with that room. Because the paint was perfect before I am starting to think I damaged the ceiling when I did the very first coat with the heater on paint dried too quickly and it has made it rough. Any ideas recommendations?

i blame the paint then!
last resort, but that is the most likely culprit if you are certain you have eliminated application problems.

We are having the same issue. Country NSW, ceiling was perfectly fine but in a tinted colour prior so wanted to paint it white. Used Taubmans easy coat flat white. Four coats later, last one with windows wide open, new fluffier roller....still patchy and see all the roller lines. Definitely think it dried too fast when the first coat or two were done. Paint seemed quite thick and gluggy, so even did a coat with watered down paint. Don't know how to fix it. Looks terrible. druving us nuts.

Did either of you end up fixing the ceiling and what did you end up doing to fix it?