Does it matter if undercoat and topcoat are different colours?

[freefriday]

Just had a quote for some decorating work. To keep costs down decorator suggested an undercoat of white emulsion followed by a topcoat of my preferred colour Dulux timeless. The walls are a creamy colour at the moment so no deep colours to cover. This seems sensible but neither of the other decorators who gave me quotes suggested it, which makes me think there must be some problem with this approach. Is there?

I'd be surprised if a single coat of the colour was enough to give a flawless finish. When painting over dark colours I've done cheap white undercoat then two coats of the colour on top.

I did a white undercoat with colour on top for some rooms and was happier with how those rooms looked compared with 2 coats of colour. I did the whole house myself in 5 weeks so was in a position to compare.

I will do the white undercoat next time I paint as standard. I was really happy with the results.

You'll probably need two coats of the colour for a good finish but I've had white undercoat on almost all my walls and it gives a lovely finish nice and cheap.

When I didn't do it I needed 3 coats of dulux because it was uneven underneath

I had half my last house in Dulux timeless done with a white undercoat then one coat of the colour on top, as it is such a pale colour it was a great finish (I usually do at least two coats when changing colour). I was expecting to have to go round and maybe do a few touch ups but couldn't find any faults.