Decking Finish Problems - Sticky Issues

We’ve covered decking finish problems in some detail already. But some issues are more common – and cause more grief – than others. This week we’re going to look at the common problem of stickiness, where for some reason the decking oil you’re applying just isn’t doing what it says on the tin. We’ll also look at how to remove old finishes so you can re-apply lots of lovely oil, and provide sensible advice about what NOT to do!

Wooden Decking

Sticky garden decking – What to do about it

You’re doing the decent thing, keeping your garden deck in apple-pie order. But when it comes down to actually applying the decking oil, or re-applying more coats, everything seems to be going pear-shaped. It’s sitting on the surface instead of being absorbed, and you’re getting into a right pickle. So what’s all this horrid stickiness about, and how do you fix it?

4 reasons why decking oil goes sticky

1. Over-application – where the oil isn’t penetrating the surface properly
2. Issues around using an oil over a non-compatible product like a decking stain, varnish or paint
3. Not enough preparation – for example, trying to use a decking oil over mould or algae
4. Problems with new hardwood decking, which is already naturally oily

What’s the problem?

If the decking oil you’re applying has gone sticky and isn’t being absorbed properly, your number one reason – assuming it’s new decking – might be the type of wood the decking is made of.

If it’s a brand-new deck, is it made from hardwood? If so, it might already be naturally oily. Which means there’s probably nothing wrong at all – the wood might be oily enough in the first place or even pre-treated with an oil. Some new hardwoods, especially exotic ones, are naturally very oily indeed, and you might find they absorb very little oil, if any at all, at least until they’ve aged a bit and seen at least 3 months of our famously awful British weather!

Over-application is a simple one. If your deck has been happily absorbing plenty of oil then suddenly stops, it’s probably because the timber is already ‘full’ and can’t absorb any more. All you need to do is stop trying to apply more and wipe off any excess with a lint-free cloth.

Some people try to take shortcuts, or don’t fully understand how various decking products work, for example, trying to add an oil over the top of a non-compatible decking stain, a varnish or even a paint. If that’s what you’re thinking about doing, stop right now – it simply won’t work! Decking oils will only work on bare wood or on decking that has been previously oiled. If your garden deck has been treated with a product that forms a protective film on the surface, sometimes characterised by cracking, peeling or flaking, it will have to be fully removed before adding a decking oil.

Decking Oil Applied

The same goes for mould and algae. It might be tempting to just paint decking oil over the top and hope it disappears, but it won’t work. Mould and algae tend to penetrate into the surface; they don’t just sit on top of the wood. And oiling them won’t kill them off. They’re living things and they will only die when treated with a special wood fungicide and mould killer, such as Barrettine Mould and Mildew Cleaner.

Many of the best anti-fungal products for wood kill the mould or algae and also prevent it coming back, which is an excellent idea and buys you more time in between maintenance sessions.

How to remove decking oil

If you’ve taken things too far and need to remove decking oil, or you want to remove an old decking oil and use a different finishing product like a stain or varnish, how do you do it?

Oils soak into the wood rather than just sitting on the surface, so while it’s easy enough to sand them off at surface level, it’s very difficult to get the product out of the grooves. If your deck is oiled, it’s best to use another oil rather than try to remove it and replace it with a stain or paint. Oils are, after all, the best product for decking because they penetrate the wood and protect it so much better, for longer, than something that just sits on the surface, and they let the lovely natural wood grain show through.

There’s a lot of talk online about getting rid of decking oil and replacing it with stain or paint, but the advice is always the same – it’s a huge challenge and you’re probably best off letting it lie. You could try white spirit or a jet washer but even they are far from ideal. Your best bet is to stick with oils. Here’s why…

• Sanding only works when the deck is smooth, not grooved, and it won’t remove oil from the grooves
• You can use a jet washer to clean decking finished with oil but it comes with risks of its own – you could damage the wood surface or contaminate the soil as the powerful jet of water pushes the finish out of the wood onto plants and into the ground
• If you really want to re-treat your decking with a sealer (even though sealers aren’t the best idea for decking), you might be able to remove your oil-based finish with white spirit… on the other hand you might not, and it’s an awful lot of work

Restored Timber Decking

The easy way – Replacing other decking finishes with oil

Rather than try to remove an oil finish and replace it with something that won’t do as good a job – like a stain or varnish – it’s always easier to remove a non-oil finish and replace it with decking oil. A decking stripper, for example, is a great way to get rid of many decking stains and paints so you can replace it with a lovely oil.

Make life easy with a good decking oil

If you want to re-treat previously oiled decking with a fresh coat of oil – which is what we’d recommend – it’s a much easier job. You won’t even have to remove all the old oil. Just clean the surface thoroughly using a good-quality decking cleaner, which will get rid of the dirt, then re-oil it. 2–3 coats should do the trick. If you’re looking for a great-quality decking oil, we highly recommend Holzol Decking Oil.

How to maintain a perfect decking oil finish for longer

As a rule, the better you maintain your deck, the less frequently you’ll need to re-oil it.

• You can’t beat a simple brush for a start, keeping the wood surface free of mud, soil, leaves and so on. Regular sweeping makes a huge difference to the life of a deck
• Cleaning is your next job, regularly using a [product name missing] to get rid of moss, mould and algae and prevent regrowth for as long as six months
• Re-finish your deck with oil whenever it starts looking tatty or worn, to help prevent damage before it starts to happen

Need help with your decking project?

For more information about decking treatments and their uses, contact our team of resident experts who are always on hand to help with project advice and product recommendations.

We love to see before, during and after photos of any decking project. If you would like to share your pictures with us and our followers, send us your photos or share on our Facebook, Twitter, Pinterest or Instagram pages.

Other great blogs that discuss decking

• Decking Oil or Stain, Which is Best?
• How to Make Decking Non-Slip
• 7 Common Decking Problems and Solutions