Do you need undercoat when repainting?

Asked By: Jerzy Fettweiss | Last Updated: 23rd May, 2020
Category: hobbies and interests painting
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Most surfaces require two coats of paint, and if you're painting over a dark colour or a new wall, you'll probably need an undercoat. That said, many paint companies now offer “one coat wonders”, so it's worth having a good browse of the paint shelves.

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Correspondingly, do you need to use undercoat when repainting wood?

the wood will need a decent coat of primer (or two) followed by a spirit undercoat. some of the better gloss paints are self-undercoating, however a primer is still necessary. and as it is bare wood i would undercoat as well, even if it is a self-undercoating gloss as it will help build up the opacity.

Similarly, do you have to remove old paint before repainting? If you are going to repaint your house and your new paint is different than the old paint, you should first scrap the whole old paint and then apply only new paint. If existing paints are whitewash and distemper, you should scrap the whole paint first.

Beside above, can I just paint over old paint?

Priming is best. If you have to do two coats of paint to cover the old color, why not use a good primer or primer/sealer and one coat of a good paint? Most people will say otherwise, but primer will stick to old paint a lot better than new paint will. Use one coat of primer and one coat of paint.

Can I paint over gloss without sanding?

If you want to update semi-gloss painted walls but don't want to sand and prime; or, if lead-based semi-gloss walls prevents you from sanding, it is possible to paint over semi-gloss walls with a satin-based paint without sanding or priming. If it's water-based, use a water-based satin paint.

23 Related Question Answers Found

Is primer and undercoat the same thing?

While the primer paint is used right before painting a new surface, the undercoat paint is used before painting a surface that has been painted in the past. In other words, an undercoat can be a primer but a primer is never an undercoat. Primers work best on flat wall surfaces and low-gloss ones.

Do I need to undercoat over old Gloss?

If you want to paint over gloss with gloss there's no need to use it. Just give the surface a clean and sand before painting.

How many coats of undercoat should I use?

Once the undercoat is dry (normally two to three hours, but check on the tin), apply another coat on top. Two layers of undercoat should cover any darker paint finishes underneath and also helps to build a better base for the gloss coat.

Can you paint over glossy wood?

You can paint over stained wood, painted wood and so much more with this simple method. To get paint to adhere to wood, you have to sand it, to rough up the surface. This allows the paint to grip the surface, especially with anything that's varnished. Liquid sandpaper dulls a glossy surface, with far less effort!

Do I need to use primer on already painted wood?


Paint will not adhere to bare wood unless it is primed first. Generally, you do not need to prime painted wood to promote adhesion; however, there are instances where the opposite is true. You need to properly prepare painted wood for a fresh finish, or peeling may result.

Should I sand before painting wood?

Sand the Primer to Make It Smooth
Because of primer's uneven texture, it is necessary to sand it down before painting. Use very fine #220-grit sandpaper, and apply light pressure to prevent gouging the primer.

Do I need to sand before painting?

While sanding is not required for every paint project, rough spots on walls, whether they have been previously painted or not, need to be sanded before they are painted to ensure the paint goes on smoothly. For previously painted water-based paint, sand with a fine-grit sandpaper.

Do you have to sand off old paint before repainting furniture?

There are times when you can skip sanding furniture. However, before painting it, you might need to degloss it. If the piece you are painting has any sort of finish on it that is shiny, slick, glossy, semi-glossy, even satin, then you need to degloss it before painting it.

Do I need to wash walls before painting?


When to Wash With Soap and Water
As noted above, most paint manufacturers recommend that you clean walls with at least mild detergent and water before painting. Although modern paints are so good that they bond well to almost any surface, it will adhere best to surfaces that are perfectly clean and smooth.

Why does my ceiling looks patchy after painting?

Patchiness can happen if you don't apply enough coats of paint. If you don't have enough paint on your roller, it can leave behind patchy areas. Likewise, too much paint on the edges of your roller can cause thicker areas that make the wall seem patchy.

Is it OK to paint over dirty walls?

You can paint over a dirty, glossy, chipping, and flaking surface, but don't expect your handiwork to hold up over time. For new paint to stick, your interior or exterior surface needs to be clean and free of dust that could interfere with your paint's ability to adhere to walls, trim, and ceilings.

How much should you sand before painting?

Apply a coat of primer, allow it to dry completely according to manufacturer's instructions, and then sand the entire piece again with a finer sandpaper--around 220 grit. Clean the surface with a tack cloth, and you're ready to paint.

How do you paint over peeling paint?

Repaint a wall with peeling paint to repair and restore the wall and make it attractive again.
  1. Lay down the drop cloths to cover the floor under the wall.
  2. Scrape away as much loose paint as possible using the paint scraper first and then the wire brush.
  3. Repair any holes or cracks in the wall with the patching compound.

How do you paint over already painted wood?


Sand rough areas and wipe away dust with a tack cloth. Apply two coats of stain-blocking primer and allow it to dry between coats. Try using a clear primer if you want the wood's grain to be seen through the paint. Roll or brush on two coats of latex paint in the direction of the wood grain.

How many times can you paint over paint?

Repaint the wall with at least two coats of your new color. If you are painting over a darker color using a lighter one, you might need more than two coats to prevent the previous color from showing through. If you the surface is still fine and you just want to cover up, it is alright to repaint painted walls.

How do you paint over peeling exterior paint?

How to Repair Flaking Paint
  1. Using a scraper, wire brush, or 80 to 100-grit sandpaper, remove any loose or peeling paint from the damaged area.
  2. Using a putty knife, apply a thin layer of patching material to the damaged area.
  3. Use 220-grit sandpaper to smooth the patched area and make it even with the surface.