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Top Tips on how to paint a wall

Summer is in full swing and repainting interior walls is one of the easiest and quickest ways to freshen up your home. But it’s a home improvement project that can quickly turn into a DIY disaster if you’re not careful. Follow these top tips to paint like a professional.

It’s all in the preparation

So, you’ve got your tins of paint and are ready to start, but that doesn’t mean slapping on a new coat of paint right away. There’s a lot of preparation to the wall that you’re going to paint that must be done first. No paint, regardless of how many coats you apply, will hide a cracked or pockmarked surface. “Preparation is a massive part of the job because if you don’t fill in all the cracks on a wall, you won’t get a very good finish,” said Graham, who has been a decorator for 26 years.

Wash down the walls

Before painting, wash down the walls with a clean sponge and sugar soap solution mixed with water. “You can get sugar soap solution in liquid or powder form from most decorators’ merchants or DIY stores. This should get rid of any cobwebs or dirt like fingerprints,” said Graham.

Patch every hole and rub smooth

Then carefully inspect the wall you’re going to paint, and scrape, patch and sand every crack and hole. Use a filling knife to fill and repair any imperfections. “If there are any cracks in the plaster, you need to rake them out to form a V-shape as a key for the filler to hold onto.

“If it’s just surface cracks, then a fine filler, like Polyfiller, can be used. On the filler packs, they tell you how deep a crack it’s suitable for. The joint between the ceiling and top of the wall will often crack and you can use a mastic or decorator’s caulk to fill that.” There may also be gaps between the skirting board and walls and down the side of window frames which can be patched with decorator’s caulk too.

“Once all the cracks are filled and the filler is dry, then sand the whole wall and dust it off,” said Graham who uses a power-operated sander with a dust extractor. If you don’t want to spend hundreds of pounds on a power tool, you can also rub down walls with sandpaper and dust off with a decorator’s brush.

Painting a room
Painting a room

Masking tape

As a professional decorator, Graham has a super-steady hand and only uses masking tape along the bottom of the skirting board to protect carpets and wooden floors. But amateur house painters will find it easier to mask surfaces adjoining the wall they don’t want painted. Tape masking tape to skirting boards, around the floor, windows, door frames and the ceiling.

Paint brushes

You can buy inexpensive paint brushes, but you may be better off investing in higher quality ones. “You need to choose a good brush,” said Graham, adding: “I use Purdy brushes which are quite expensive, but they last and hold a good amount of paint.  Cheap brushes often have loose bristles that can come off when you paint and stick to a wall.” Brushes come in different sizes, so you’ll need to consider the job you want it to do and the type of paint you’ll be using. Synthetic bristles are used for applying water-based paints whereas natural bristles are best for oil-based paints. “You can get badger hair brushes which are used by specialist decorators but for more general use, I use mainly synthetic brushes,” said Graham.

Drop clothes

Drop clothes are essential to protect furniture and floors from paint splatters and spills. Plastic drop clothes are cheap but are mostly binned after just one use whereas canvas lasts longer and is less of a tripping hazard.  Graham said: “I prefer cotton twill to plastic drop clothes. I just find plastic tends to be slippery underfoot.” Or perhaps, you have an old sheet lurking in the back of your linen cupboard that could do the job. Remember to roll up any rugs and remove paintings and pictures from walls.


When painting interior walls, start with a technique called “cutting-in” to give a nice, straight edge. To cut in, paint along the top of the wall in a horizonal line, using firm and steady strokes, back and forth. “I use a two-inch wide paintbrush for cutting-in,” said Graham who uses the same technique to paint above the skirting board and around windows, door frames, light switches and sockets as well as corners.

Paint roller and tray

A paint roller is better than a brush for covering large areas of wall.  Graham said: “I use a nine-inch roller and frame. You don’t want to use anything smaller than that really.”  Pour the paint into the tray and dip the roller in. “Get a reasonable amount of paint on the roller but don’t overload it and apply to the wall with a firm, even pressure. Start at the top – at the edge where you have already cut-in a two-inch strip of paint - and roll down to the bottom. Roll up and down a couple of times. Then fill the roller up again, to paint another nine-inch section with fresh paint but go over the last one slightly so you have a wet edge all the time.” This prevents any gaps. Continue until you have painted the whole wall, then wait for it to dry and repeat. “You will need at least two coats of paint,” said Graham.

Extension pole

If you’re painting a ceiling or wall, it’s worth buying an extension handle for your roller. They are easy to find in DIY stores. It saves you lugging around a ladder and climbing up and down steps. “It’s definitely easier painting with an extension roller and you get a slightly smoother finish then a roller on its own,” said Graham.

Sand wall before applying second coat of paint

When you have finished the first coat of paint, wait for it to dry and then rub down with 180-grit sanding paper for a professional finish. “It gets ride of any bits or blobs that may have got on the wall from the roller,” said Graham.

To prime or not to prime?

A primer or undercoat is only really necessary when you’re painting over a dark colour, said Graham. “If the wall is a very dark colour, for example red or blue, and you want to change it to a lighter colour like cream, you probably should put white emulsion on first which will block the darker colour. But if you’re painting white on white, you don’t need an undercoat first and can just use two coats of white emulsion.”

Paint Equipment
Paint Equipment

What about radiators?

There’s no need to remove radiators when you paint a wall. “If you need to paint behind it, use a four-inch radiator roller with an extra-long handle that’s suitable for tight spaces and can go up and down behind it. I only take radiators off the wall when I absolutely have to, for example stripping wallpaper,” said Graham.

Look after your brushes

It’s important to clean your brushes so they are ready to use next time and are not stiff with paint.  Wipe any excess paint left on the brushes on to newspapers or a rag. For emulsion paint, rinse the brushes under clean, warm water and pat dry with a paper towel. For oil paints, soak the brushes in white spirit to clean.

Take paint to be recycled

There’s no point storing half-used pots of paint in your shed or garage for years. “If it’s older than six months, it will have separated, and you can’t paint with it. You need to take it to a council recycling centre to dispose of as you can’t pour paint down the drain. Some decorating merchants will also take back old paint,” said Graham.

Any other tips?

Remember to always read the instructions on the tin of paint.

Wear gloves (and long sleeves) when sanding by hand to protect your skin. Sandpaper has lots of small pieces of glass grit that can work its way into the skin, causing damage and irritation. If this happens, it can take months, or even years, for skin to fully recover.

Remember the importance of proper ventilation as build-up of toxic fumes from the paint can make it difficult to breathe. Before any interior painting begins, windows should be opened as wide as possible inside of the room that’s about to be painted and throughout your home. Then leave windows open for 12-24 hours. It can get cold in winter with windows wide open, so plan this home improvement project for warmer, summer days. 

Any other tips? Graham said: “Just be careful and methodical in everything you’re doing and there should be no paint splashes or spills. If you’re up a stepladder, make sure the paint pot isn’t at the bottom, so you don’t step in it!”

Paint and Brushes
Paint and Brushes