When it comes to home improvements such as painting – preparation is key, so in this blog we’ve tackled the important question: how to prepare exterior walls for painting.
While you might be tempted to take shortcuts to save time in the short term, not preparing your surface properly will only cause issues down the track.
In this blog we give you step-by-step instructions for prepping pre-painted surfaces, timber, aluminium or galvanised iron, and masonry surfaces.
Did you know? Detailed application guides for Globalcote products are available for download on our website. Get started here!
Preparing Your Surface For Painting
Before you put a coating on any surface it must be:
- Sound
- Clean
- Dry
- Free from surface contamination
The complete preparation process varies slightly for different substrates.
Let’s take a look at a few of them and what’s required.
1. Surfaces that have been painted before:
Pre-painted surfaces require the following:
- Ensure the surface is sound (that is, can withstand additional coats of paint).
- To test, cut a cross hatch through the paint with a razor blade and place a piece of sticky tape over the cut. If the surface is pulled away by the tape, the surface is not sound.
- Examine several areas before you determine if the surface coating should be removed.
- Any surfaces which are unsound should be stripped before repainting.
- Use an appropriate filler to patch up cracks and holes.
2. Timber:
If working with a timber surface, here’s what you need to do:
- Sand weathered timber back to clean sound wood and then dust down
- Use suitable filler to fill imperfections. Then sand, smooth and dust down
PRO TIP: When brushing new timber apply in the direction of the grain.
3. Aluminium or Galvanised Iron:
Here’s what you need to do for metal surfaces such as aluminium or galvanised iron:
- Thoroughly clean and degrease new surfaces
- Remove any chemical treatments which may impact adhesion
- Clean and prime any rust areas with a suitable rust primer
4. Masonry surfaces:
To minimise the risk of cracking, porous surfaces like bricks or cement need a little TLC before painting. This includes:
- Be fully cured (28) days prior to coating
- The surface’s moisture content needs to be lower than 6% at time of application
- Make sure the surface is not subject to hydrostatic pressure
Cleaning Your Surface Before Painting
Regardless of which surface you’re working with, it’s always wise to properly clean prior to painting. Depending on the products you’ll be using, you may also need a primer (shown in Step 4 below).
Step 1: Wash down any surface with detergent. Then use clean water to rinse.
Step 2: Use bleach to treat mould and use fresh water to rinse thoroughly.
Step 3: Use a suitable filler, putty or sealant to fill in any holes and cracks.
Step 4: For any surface which has been coated with an enamel or varnish product, we recommend sanding and then using Globalcote’s 3 in 1 Multi-Prep primer as an undercoat to ensure adhesion.
Globalcote Elements range is ideal for interior and exterior applications and includes:
- Low VOC Interior Paint
- Low VOC Exterior Paint
- Water Based Enamel (100% acrylic)
- Ceiling Flat
- 3 in 1 Multi Prep (sealer, primer and undercoat!)
- Wallboard Sealer & Undercoat
How to prepare exterior walls for painting
No one wants to do the same job twice. That’s why preparation before painting is hugely important.
Not sure where to start? Talk to the experienced Globalcote team about the best products for your paint job – from preparation to final coat. Call 1300 928 826 or enquire online here.
Globalcote is fast becoming a leader in the manufacture of specialty acrylic exterior coatings. We have an extensive product range available is a wide variety of colours.
Our product range includes roof membranes (some with heat reflective properties), primers and sealers, surface treatments, concrete coatings, interior/exterior house paint and pool paints.
We have an enviable reputation trusted amongst professional tradespeople and paint retailers Australia wide and supply a wide network of retail stores throughout Australia.
For an Australian owned and operated company thinking globally and acting locally, call Globalcote on 1300 928 826.
