Beneath the woodchip

[Ky12]

Hi,

I have removed all woodchip. This left a yellow glue which I have since got rid of and I'm now at bare plaster.

What do I need to put on now? A primer, a mist coat, straight on with top coats??

Thankyou

 

[misterhelpful]

Bare plaster needs to be sealed first. This would normally be a mist coat of watered down emulsion but, as your walls have been previously papered, and may still be somewhat contaminated with paste residue, a coat of Zinsser Gardz would be the safest bet. This will seal the surface and allow you to paint directly onto it. Just ensure you sand down any rough spots before applying the Gardz.

 

[Ky12]

That's really helpful thanks.
So wash the walls with sugar soap, sand high spots, fill low spots and sand these down, prime with guardz all over the whole wall then top coat??

Or do I sugar soap wash again just before priming?

 

[misterhelpful]

You can use sugar soap if you feel it is necessary but to remove the paste residue you can usually do the same job with a sponge/scourer and hot water. If you use the sugar soap then make sure you rinse that off with plain water before proceeding with anything else.
Having said that, if using the Gardz, it isn't essential to remove all paste residue because the product is designed specifically to seal it in, but try and remove as much as possible. You will need to even out any imperfections before applying it though. If you want to go down the mist coat route instead, then you must remove all paste residue before proceeding. Also, ensure that the surface has dried after being washed before applying anything to it.

 

[emilybronte]

If you are planning to paint the walls afterwards, and you are concerned that the surface is not 100% plaster-perfect, you may want to line the walls first with a good quality lining paper such as Wallrock Fibreliner. It addds to the cost slightly (approx £1.50 per square metre inc. adhesive) but it gives you a much more satisfactory finish with old or imperfect walls. If you are careful when hanging it, the joints should be invisible and the surface looks very much like new, smooth plaster.

I did this in the end in the sitting room of my own house, having spent 3 whole days sanding and filling and re-sanding the living room (and gibbering a lot) trying to get a perfectly smooth finish (on 150 year old walls which had been mightily abused over the years).