Why do you paint emulsion on lining paper before filling?

[taz15964]

Hi there,
I have a builder and his team who are are lining walls for me, 6 rooms in total.
They have lined the walls with a 2mm gap between each sheet and they just started before I stopped them to fill the gaps with filler without putting emulsion on first.

I have read that you have to paint emulsion first before filling and rubbing down, but why is that?

And if these guys have messed up, is there a solution to fix this as I have read people saying leave a small gap and others say but the joints of the paper.

Any help explaining why this is the case would be greatly appreciated.

Tom

 

[dcdec]

Its bad practice to do what they are doing, a competent decorator should be able to line a room with butted seams invisible to the eye.
There are two main problems with filling seams.
1. The filler is a different texture to the paper and can be very noticeable when looking down a painted wall.
2. When you go over the filler with a roller it can flex and crack, even more so with the next point.
The paper is porous and will suck the moisture out of the filler, so a thinned coat of emulsion on the area you wish to fill will satisfy the porosity of the paper. The filler will be 'brittle' and is likely to crack as i mentioned if its not primed.

He'd be better off using a non woven LP as there's no expansion or shrinkage, its a bit more idiot proof.

 

[taz15964]

So leaving a 2mm on purpose is not common practice? Or is it just simply wrong and I need to have a word with them?
Sorry I'm now worried the finish will be terrible.

Thank you for the help.

Tom

 

[xr4x4]

Just to add fuel to the fire, you will always see joins on paper, no matter how well it's done.

With filler, I would assume its possible to create a virtually invisible join.

I say this with no actual experience of filling the joins.

 

[dcdec]

Sure an invisible join can be created but it will often cause the problems i mentioned. I'd say its not common place but there's a lot of people calling themselves decorators that have had no training or knowledge passed to them, so bad practice is increasing in the trade. I can line a room and you won't see the seams, and i don't mean to be arrogant in any way its just the standard i was taught.

As for your builder, i can't condemn a guy without seeing his work, his method may work well for him, my biggest worry would be the change in texture and if its visible once painted.