Interior Painting Preparation

Interior painting preparation is the most important part of your painting job. Preparations make your paint hold, and they make your new paint coats look good. The time it takes is well-spent: it will make your paintjob last for the longest time.

interior painting preparation supplies

Interior painting preparation

Any old surface can be made to look like new, if you invest some time in it. Here I'll go into interior painting preparation for woodwork and other trim. Click here for more on:

Every job needs its own preps

The amount of preparation needed depends on the state of your surface, your old and new paint sheen, and the level of durability you’re going for.

  • Oil based paint always needs sanding and a primer. Check here to see how to know if it's oilbased
  • Holes always need taking care of – unless you like it ‘shabby chic’
  • Chipping and loose paint layers (or wallpaper) need to be taken off.
  • If the old paint layer is high-gloss, do at least some light manual abrasing
  • For painting matte, some irregularity is OK (it wil be hidden), but highgloss paint needs a flawless surface. Highgloss paint puts a highlight on every drip and dent.
  • If you want your paint coats to hold: do some careful abrasing and cleaning, and apply thin coats
  • Before sanding, degrease the old paint with water and ammonia. Your sandpaper will last much longer, as it won't get stuffed.
  • Paint coats can’t be layered untill infinity – if there are more than 5 underneath the surface, consider taking them all off (check here for an eco-safe paint stripper).

door in need of painting, and lots of preparation

Primer paint

The right primer can help you to block stains or have a better hide. Some primers can be ordered in the same color as your top-coat, which saves you one or more paint layers. However, when you need to block fire-damage, water-stains or nicotine, a heavy-duty primer is needed. Click here for more on primer paints.

Surface repair

The first step in interior painting preparation is checking your surface:

  • how well stuck is the old paint layer
  • irregularities – holes, damages

First check the ‘hold’ of the old paint layer, by scratching a little (softly at first, to avoid unneccesary damage). If the layer is well stuck you can paint over it
with the right kind of paint. If bits are loosening: use a shave-hook and scrape off as much as you can. Take a sharp shave-hook in the right form (to avoid changing the shape of your painting surface). If you don't want to take off everything: use abrasive pads and fillers to level the surface.

Filling holes and small damage repair is best done in between the abrasing, but rough repair (replacing pieces of wood or woodpanel) is best done before starting your interior painting preparation.

Paint removal

For a good painting preparation, sometimes it’s necessary to remove old paint layers. Reasons:

  • Your object already has too much paint layers. When your wood trim is covered in a whole pack of paint layers, it needs to be stripped.
  • Your object was painted with the wrong paint (and is peeling, chipping or crumbling off).
  • Durability investment - old paint is a risk, it may chip. Taking it off is a time investment, but you won't have to again for a long time. When the old paint layer (and its primer) comes loose, you can shave-hook, scrape and sand, and then caulk - or just take it all off.
  • Getting the natural wood-look back. Some staining will probably remain visible, but once the wood fully shows again, you can stain it like you do untreated wood.

Paint removal can be done chemically or mechanically, or by applying heat - check here for paint strippers. For mechanical removal, we have shave-hooks, abrasing machinery and abrasive paper or pads, and the heating gun. With a heating gun: be careful near windows (they might crack because of sudden heat), and only use it if you plan to do a full paint removal. If you can do with partial removal (for the rougher jobs, with not much paint layers on the surface already), first take a shave hook and take off what can te taken off. After that, level the edges with abrasive papers or machines. Another choice might be: to take all the old paint off, eventually with the help of chemicals. If you do so: protect your hands, and all materials that don’t need paint removal (and the floor). This stuff is really agressive, I really advice to use an eco-safe paint stripper. Put it on with a brush (use gloves!), let it work in for a while, then take it off with a sharp shave hook. Try to find the right shape of shavehook for your job - you don't want to change the shape of your woodtrim.

Sanding tools

Sanding machines can be handy for big surfaces, but for wood trim you might just as well take some extra good, fresh and sharp paper or abrasive pads. Sharp paper does a lot of the work for you, and it’s good to work your fingers into the woodgrain. If you use machines: take the right shape for the job. A round spinning sander is great for bigger and easy surfaces (doors), a triangle sanding machine is good for difficult corners, and a strip sander is good for floors. A strip sander needs to be kept moving, or else it might do too much damage. Change the paper in time, to keep your work effective.

If you choose the noble handwork: take soft abrasing pads. They protect your fingers from sharp little stickouts (nails etc.).

Abrasing (partly) removes the old paint layer. But it also creates a fine structure on which the new paint coat can get a “grip”. For removing old paint and coarse irregularities, use coarse abrasive paper or pads. For normal sanding, use a medium grained paper, and finish abrasing with a fine paper. If the old paint coat still looks really good, you can do with only fine paper. Abrasive houshold equipment can also be used here.

If you’re in a real hurry, and have a solid good-looking surface to paint on, you can do your interior painting preparation by just washing the surface with a fluid abraser, a liquid agent that 'bites' to make your surface ready to paint over.

Filling and repair

Filling is best done in between the abrasing phases – like: after the medium and before the fine abrasing. Then the filler also gets a good grip on the painting surface.

there are many filling products – make sure you get the right material, and try to find one that dries out quickly. It says in the manual how long you should wait before painting it over. For filling holes in real wood, consider taking a wood filler that’s also made of (the same kind) of wood.

Apply the filler with a painting- or a palette knife, as neatly as you can – after it has dried, you can abrase off eventual rims.

Cleaning

Cleaning and degreasing is an important part of interior painting preparation: the surface should be free from fat (fingerstains) and dust. Clean it with ammonia and water, or use a paintgripper fluid. After drying, you can start to paint.

Other stains also need removal. Permanent text marker stains will bleed through in your new paint layer. In this case, priming with a blocking primer is necessary for interior painting preparation. Als bad smells can be eliminated this way. Consider using a shellac blocking sealer or primer. Shellac needs to be painted over with either latex or oil-based paint. Latex can be made stronger later, by finishing it with a polyurethane laquer.

Interior painting preparation for highgloss paints

Highgloss paint needs the most elaborate preparations, to look good. It needs a flawless surface. Just sanding usually isn't enough: you have to use fillers for equalizing, and sand again. But when it’s done, it is the most durable paint coat – and if the preps were done right, the most classy as well. An offwhite panelled door can look stunning, when done in a perfect highgloss. Other paint sheens maybe can do with a little less preparation – but cleaning and light abrasing is always a basic procedure for interior painting preparation.

Related pages:



Oil Painting Techniques

Acrylic Painting

Watercolor painting

Color Schemes

Interior Painting techniques

Interior Painting Ideas

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