# Forum Home Renovation Plastering  New Plasterboard - Undercoat and Painting Questions

## dilbadoon

Hi All, 
Sorry if this is more appropriate for the painting section, but I am chasing advice specific to plasterboard.  We have just finished the walls and cornices, and are ready to get to painting.  
I have never painted fresh plasterboard so hopefully you can shed some light on these issues:
1.  Do I need to undercoat?  We are trying to keep the budget down, but obviously not at the cost of quality, so if it needs undercoating i'd be happy to do it, would prefer an extra top coat if that's all that's needed.   If it does need undercoating is it just over the joints or should the whole sheet be covered?
2.  I think I've read somewhere to only use oil based paints on plaster sheet/joints rather than water based, is this the case?
3.  Is there a time limit on how soon we should paint?  We were wanting to focus on one room at a time, doing the kitchen first so the lounge may not be painted for a month or so?   
Any other tips much appreciated! 
Cheers.

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## REBSS

All new boad needs to have a sealer coat applied first. Water based paint is best used on walls and oil based on trim etc etc.
cheers

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## melton2

i would undercoat the plasterboards. it not only helps seal the boards as stated, but helps the top coats to bond better. paint the whole sheet, not just the joints. 
REBSS is spot on with when to use water/oil base paints.. 
and there is no time frame on when the plasterboards need to be painted. just make sure that they stay nice and clean in the mean time...

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## dilbadoon

Great, thanks guys.  :Smilie:

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## TheHammer

The raw compound is very porous. If you didn't use undercoat/primer the first topcoat will get sucked up into the compound. The other thing that often happens is the wallboard gets furry after the primer. You will need to sand that mess off. You do not want to sand topcoat. Its too soft and sands badly. Any waterbase primer is fine for wallboard. 
They do make wallboard sealer like Tradex. Its $50 cheaper than 3 and 1 if you buy 15 liters. Its ment for new wallboard. 
You absolutely need to get the dust off of the walls before painting. Get a bucket of clean water and a sponge at least as big as your hand. You need to damp sponge everything and constantly rinse the sponge in the bucket. You do not need to use any detergent like Sugar soap. Clean water is fine. Don't get the compound wet or you will start removing it. Basically wipe with the 4 edges of the sponge then rinse. Have fun.

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