How to maintain decking
After a long winter, your decking may be looking tired, mossy and be slippery under foot. If this sounds familiar and it's been a few months since you last gave your decking a spruce up, chances are it may be starting to rot away. Our DIY partner and home expert Craig Phillips shares his advice on giving your decking a spring time health check.
Read on for more information about the most common problems with decking and how to solve them or jump to the following sections:
- Removing mould and mildew
- Staining and retreating
- Repairing very soft decking
- Replacing joists
- Tidy up old decking screws
Getting rid of mould and mildew is a simple task. Get yourself a bucket of hot, soapy water and a good hard yard brush and scrub away a square metre at a time. Ideally, get yourself a powerful jet wash and set the nozzle to produce its most powerful jet. Give the planks a good clean, making sure you get right into the grooves and between the planks.
Once you have rinsed the whole area a couple of times, leave it to dry - maybe overnight. Then, apply a clear decking wood preserver or sealant for a nice-looking, long-lasting finish.
IMPORTANT: For very mouldy decking, bleach can be used – but always check the manufacture details for the exact ratio of bleach to water and check it is suitable for your deck as you don’t want to cause damage to the timber. You must rinse the area thoroughly and always wear, protective clothing, gloves and goggles.
If your decking is looking a bit tired, it’s time to stain and re-treat it. I'd recommend doing this every couple of years. Start by cleaning the area first, following the above steps. Then rinse the whole area at least twice and leave it to almost dry out before treating. Apply a few coats of an all-in-one stain and preservative. If you only want to refresh one particular area of decking, you might need to sand the area first. This way, when you re-stain it, the new area should blend in with the existing decking. If you're going for a coloured stain that is different from the existing one, you will have to apply at least three coats, giving a very gentle sand and dust between each coat.
TOP TIP: If you are treating a large area and applying a few coats, you might want to apply the stain with a paint sprayer instead of a brush to speed up the process, or you could use a decking pad or roller. Check the instructions as you may have to dilute the stain down with water to apply it in this way. If you do chose to use a paint sprayer, ensure you protect surrounding areas by sheeting them up before starting.
If the decking is going very soft, I'm afraid this is clear evidence that your decking is starting to decay. You must deal with this straight away for two reasons. Firstly, it will become dangerous to walk on and, secondly, the longer you leave it the more it will rot and the more expensive it will become to rectify.
Start by identifying all the defective sections by pressing a sharp pointed tool into the suspect area of all the planks showing signs of decay. If you find the bradawl or screwdriver goes into the wood very easily, then mark the area affected. You will need to trim off these sections with a handsaw, jigsaw, or plunge-cutting circular saw.
Cut the planks where they cross the centre of one of the joists… most easily done with the circular saw. If you only have a hand or jigsaw, you will only be able to cut along the side of the joist. You can then either loosen the screws further down the plank and re-cut the plank so the end sits in the middle of the joist, or you can chisel away more waste until the end of the plank is in the centre of the joist. Another method is to nail a new joist to the side of the joist you have cut the decking from, to support your new lengths of decking.
Now that all the damaged timber has been removed, treat the cut ends of the decking with a preservative - a few coats are best. Next, you're going to have to replace the areas you have cut out. For more advice, watch my video on the lovehome website: How to lay decking.
When you are cutting the new sections of decking, leave a 15mm gap from the wall of your house, so air can get to the cut ends, and any rain water that runs down the wall won't go straight into the ends of the new planks. And all new timber must be treated with at least three coats of preservative so it won't happen again. It’s also worth checking any guttering above the decking, as blocked gutters could be the cause of the decking rotting next to the wall.
After removing any rotten decking, it is worth testing your joists to see if they are rotting, too. If you have caught the rotten decking early enough, hopefully you won't have a problem. Test your joists the same way you tested the planks, by pushing a screwdriver into the timber to see how far in it will go. You may find that you have to replace one or two joists. Even if you don't replace any joists, you must treat all timber below any rotten planks with a wet rot wood preserver - at least two heavy coats. I'm a strong believer that you can never apply too much wood preserver to timber used outside.
If you’ve gone to the trouble of doing up your decking by following the steps above, then why stop there? A lot of old decking has quite ragged screw holes from when the original screws were driven in. It may be worth trying to remove each of the screws and replacing them with new galvanised screws, and even cleaning up the hole left by the previous screw by countersinking it properly, or just giving it a quick sanding to remove rough edges. Just remember - don't try to remove all the screws at once! Only do a couple of them at a time.