Moving into a new home is an exciting time for everyone involved. What isn’t so great is having to deal with the mess left behind from the previous owner or tenant. Holes in walls, nicks out of your corners, bad quality hooks hung in weird locations… Speak to any renovator and they will all have a horror story.
Luckily, Sika produce a wide range of fillers that can be used in everything from movement cracks, hairline cracks and large holes in your interior walls. We are going to give you a bit of advice here about how to do the job right the first time, every time, using Sika products for a baby-bum smooth finish.
When choosing the right product for the job, you have to ask yourself a couple of questions: Has this crack been caused by movement (like cracking in interior brickwork due to settling of house or unit) or is there likely to be more movement in the future? If it’s a movement crack, the best idea is to fill the crack itself with a flexible gap sealant like Sikaflex PRO. The polyurethane formula of the Sikaflex will allow the brickwork or concrete to move without the crack reappearing.
Before you start filling any of the cracks, best practice is to wash down the area or the whole wall if you plan on painting over it at some stage – the cleaner the area, the better the filler will stick. Make sure there is no excess dust in any of the holes, and clean the area around small cracks as best you can.
If your crack is really fine, then get a spatula or knife into the crack to widen it enough to allow the filler to get in there and do its job. If it’s a hole in plasterboard, then make sure you cut away any excess paper or loose material. This will allow the filler to ‘grab’ properly and make sure it wont fall out on you.
Choose your Filler
Once your substrate is looking good, choose the right filler for the job. For large holes, use Sika Filler-105; for fine non-movement cracks, use Sika Filler-101; for movement cracks, use Sikaflex PRO. If you’re making repairs in a wet area like your bathroom, kitchen or laundry, use Sika Filler-107, which wont go soft again in humid conditions.
Apply the right filler with either a metal spatula/scraper or flexible plastic scrapers, which you can get from any local hardware store. It’s a good idea to have two scrapers, as this will be particularly helpful for nicks in corners and the like.
Apply the filler across the length of the crack. If your crack runs horizontally along your wall, fill in short, vertical strokes. If your crack runs vertically, fill in short, horizontal strokes. You don’t need to have heaps of filler on your spatula, just enough to handle in the area.
Always fill in one single stroke, and any excess product from that one scrape should be disposed of – it will be contaminated with dirt and stuff that will stop it from performing at its best. Repeat this process until the crack is filled and looks reasonably flush to the area. Don’t worry too much if its not perfectly smooth, you can fix that once is dried.
All the Sika Fillers take about 12 hours to fully dry, so if you apply your filler the night before you paint, you should be fine for sanding and painting in the morning.
If you have used the Sika Filler-105 Coarse grained filler, slightly underfill your hole so you can apply Sika Filler 101 over the top to create a super smooth finish. Once all your filler is dried, use a fine sand paper to sand back the surface flush to the wall. Once sanded, wipe down with a Chux cloth or similar to remove any dust before painting.
Applying a sealer or a primer/undercoat will help seal over the filler and stop it from looking patchy under the paint. One coat of primer and two of paint colour and you wont even be able to see the filler in the wall! The perfect finish every time!
If you need any further assistance, or have any questions regarding Sika products, please contact Sika Australia at firstname.lastname@example.org and they will get back to you as soon as they can with their answer.
* All the products mentioned in this article can be found at your local Bunnings or Hardware Store.