Shiny patches coming through the wall on matt paint?

[Fluffycloudland77]

There's an area of about 5ft long by one foot wide going up the stairs above where the hand rail was that's forming swirly shiny areas.

It was like this when we moved in 4 years ago.

I've painted two coats of Matt, then we had 7% sheen paint, now three coats of Matt paint again. Slowly in the 24hrs after painting they show again.

Do I need to stain block the area with zissiner stain block?.

It's not where we touch the walls, we don't have kids who might do so. It's spoiling the look of the hall.

Is it damp?

What's on the other side of the wall? Terrace house/garage etc? What's above? Where's your chimney/boiler etc?

I don't think so, we had a house with damp as a child.

It's a newbuild & that walls never been repaired or damaged etc.

It's a swirly pattern.

The other side of the wall is the lounge & a bedroom upstairs. The chimneys on an outside wall & the boiler vents on the back of the house.

This walls internal.

Pictures might be helpful?

I'll try tm.

What's under the Matt? Anything 'shiny' should be lightly sanded first

DH says if is swirly pattern it might be where the Ames taper has used his circular sanding machine to sand off where the tapes have been. He said you need to do a light layer of finishing plaster then sand it to smooth it in then paint it