Undercoat for internal walls of a new house

chuckles30

I'll be getting the keys for my new house in a couple of weeks and just doing a bit of research at the moment as this is all new to me. The first thing I'm going to have to do is start painting & I'm just wondering about the undercoat - do I specifically have to use 'undercoat' or would ordinary white paint do the same job? It seems to be easy enough to pick up the big 10L buckets of white paint, but not undercoat. Also how many coats of undercoat should I put on - some people say one and others two.

Any help will be greatly appreciated.

mad m

What you refer to as an undercoat is water based emulsion,you will probably need more than one ten litre bucket.For first coat mix the emulsion with some water so that it will soak in easier.If your walls are plastered you will find that the first coat will dry fairly quickly. Are you going to keep walls white?

If you are then you will need to paint walls atleast two coats,but if you are going to be painting walls a different colour in each of the rooms, then I would just put one coat of white on to give your walls a base coat for following colours of your choice.

Corkey123

Bond any newly plastered walls and ceilings with PVA before painting

mad m

MartinCorcoran wrote:

Bond any newly plastered walls and ceilings with PVA before painting

Whatever you do dont do this. Pva (Polybond) is for sealing up dusty holes before doing patching or general sealing.If you put this on newly plastered walls in my opinion the emulsion will just sit on the layer of Pva and not soak in.

But I suppose in some if not most water based emulsion paints the binder is actually (Pva aka polyvinyl acetate),jesus im rambling,blah blah blah blah blah.......:)

muffler

Im not saying this is the best thing to do but what I did was to put wallpaper paste on the walls first before painting. It acts as a sealer and prevents napping.

A good paint shop should be able to supply you with undercoats/sealer coats

mad m

muffler wrote:

Im not saying this is the best thing to do but what I did was to put wallpaper paste on the walls first before painting.

Your only meant to do this prior to wallpapering,its called sizeing up the wall.Im in disbelief you did this before painting your walls as the wallpaper paste can be acidic and attack the emulsion and cause blistering, plus wallpaper paste can work back up when wet and the emulsion will take ages to dry.

muffler

mad m wrote:

Your only meant to do this prior to wallpapering,its called sizeing up the wall.Im in disbelief you did this before painting your walls as the wallpaper paste can be acidic and attack the emulsion and cause blistering, plus wallpaper paste can work back up when wet and the emulsion will take ages to dry.

I should have elaborated a little. The paste which was a very well diluted mix was put on the bare walls and the painting wasn't done for about 3 weeks after that.

I was given this advice by a man in the painting business for over 30 years. The walls as you know will dry out unevenly and the paste would act as a sealer coat thus preventing napping of the follow up paintwork.

That was 15 years ago and I never had a problem

CJhaughey

If you are just painting bare slab, you can get 10l buckets of Dulux Supermatt for about 25 euro, these cover well and are ideal as a basecoat or if you want a very flat finish.
you can then put a topcoat of low sheen emulsion on to allow the surface to be washable.
I don't like to use wallpaper paste as it contains high levels of fungicide which I would rather not breathe.

Macy

For the normal plasterboard/skimmed rooms, we followed the instructions on the normal white emulsion. I think it was mixed up 80-20 paint to water (following advice of a mate who's a painter and decorator). For plasterboard with a skim, this and a top coat of colour was enough.

Block work and plaster though would be several undercoats and several top coats, judging from our experience with the chimney breast.

chuckles30

Thanks for all the information & tips. It's great to hear how different things have worked for different people.