How to prepare a room for decorating

prepare a room for decorating

Learn how to prepare a room and your walls like a professional painter and decorator



Preparation is the most important stage of decorating. 90% of decorating is in the preparation, get this right and the painting will be the easy part. A professional decorator knows that spending time in preparation work is the key to a flawless finish. This post will guide you on how to prepare a room for decorating.

Tools you will need:


  • Filler knives
  • Caulk gun
  • Wet cloth
  • Brush
  • Roller & roller tray (only necessary if mist coating)


Materials you will need:


  • Sand paper (120G in most cases)
  • Filler
  • Decorators Caulk
  • Stain blocker (Zinsser BIN)
  • Matt emulsion & Primer (only necessary if you got fresh plaster and bare woodwork).


Before you get started:

If you have not already protected your work area, use this blog to help guide you.

Fresh plaster

Before you do any preparation work on new plaster it needs sealing with matt emulsion. Pour the emulsion in to a scuttle or bucket, add 30% water and stir until all the water on the top is mixed in. Paint your bare plaster walls and ceiling, cutting in first followed by rolling. Professional decorators may also mist coat (watered-down layer of paint that is applied to new plasterwork) first before preparation to help spot imperfections. Another benefit of mist coating before preparation is that fillers adhere to the surface better.

Bare Woodwork

Like fresh plaster, woodwork needs sealing before filler and caulk can be applied. Most newly fitted woodwork now comes pre-primed so will not need priming again. Any bare woodwork should be knotted and checked for protruding nails before sealing. Quickly go over all new woodwork and check for any protruding nails, use a nail punch and hammer to punch the nails couple mm below the surface.

Knotting solution applied to knots helps to prevent the sap seeping out and coming through your paint later on. A modern decorator may use Zinsser BIN rather than knotting solution. Apply BIN to the knots and allow 20 minutes to dry then using a water based primer apply this to the bare woodwork.


Probably one of the most over looked tasks to DIYers. Sanding is crucial as it provides a smoother finish and allows paint to adhere to the surface better. Depending how poor / rough the surface is depends on the grit sand paper you’ll need. Most cases 120G sand paper is a good all-rounder. If you have poor oil based woodwork surface you may need to consider 80G but you would not use 80G on new woodwork or plaster as this will scratch up the surface and do more damage than good. The higher the number of the sand paper the less rough it will be and leave a smoother finish.

Sandpaper Grade Best use
80G – 120G Rough surfaces oil based painted woodwork, poor condition walls.
120G – 180G General key up on most surfaces and used on most walls and ceilings.
180G – 240G For smooth surfaces and for sanding between coats.


There are hundreds of fillers out there all with different purposes, so let’s keep it simple. For walls & ceiling Easifiller is a go to general filler and comes either readymade or in powder form. For hairline cracks you will be better using a more flexible filler. For woodwork fillers we recommend Toupret Ready Mixed Wood Filler as this is straight forward to use.

Remove any loose debris before applying the filler. A common mistake that many people make is try fill it in all at once. If you do this you will overfill it which will make it harder to sand and longer to dry. Try filling in layers to avoid these issues.


Decorators caulk is used for internal corners with gaps as caulk is designed to flex unlike most fillers. Apply the caulk bead smoothly and evenly, using a wet cloth, wet your finger and smooth off the caulk the caulk should be pushing in the gap as you are smoothing it off and not a lot sitting of the surface like pictures below.

Stain blocking

Most rooms we come across have a stain of some sort from water leaks, blue tack, drink spills etc. I recommend using Zinsser BIN for most stain blocking. Bare in mind if you got a current water leak still occurring this must be fixed and left to dry out before stain blocking.

If you would like to know more on how to stain block please follow this blog LINK………

This blog is only scratching the surface of preparation covering most common to dos in prep. This is usually the longest part of decorating. Take a look at our post on how to paint a wall next.


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