Yes, you absolutely need to clean wood thoroughly before oiling to remove dirt, grime, old finishes, and mildew, ensuring the new oil penetrates deeply for a long-lasting, even finish; skipping cleaning can trap contaminants and ruin the look, so use a specialized deck cleaner or sugar soap, scrub well, rinse, and allow it to dry completely before applying oil.
I would first wipe it with soapy water. Dawn dish detergent cuts grease well. You need to dry wood immediately when using water. Then I would wipe it down with a rag damp with turpentine. That will remove old oil. Then apply new oil. Oil takes about a week to dry but it is worth it if you love that bare look.
Sand the wood with 120-grit sandpaper. This helps you to remove any rough edges and create a smooth surface ready for your oils. The oil has a better chance of seeping deeper if the wood is smooth. Using a tack cloth, wipe away the sanding dust and ensure the surface is once again clean.
Any dust, dirt or grime left on the timber will keep the oil from soaking in and may ruin the look of your deck completely. Always clean your deck with a sugar soap solution or specialised deck cleaning product and a stiff decking brush, then hose thoroughly and dry before applying an oil or treatment to your deck.
Start with using methylated spirits to remove any dirt, grease, oil or stains from the timber surface. If you have previously polished the surface remove it with a polish remover. You'll also need to remove any scratches or blemishes from the surface by sanding it down with 180-240 grit sandpaper.
The golden rule when sanding is to always sand with the grain. Sanding along the wood grain prevents scratches, maintains surface quality, and produces a smoother finish. Sanding against the grain creates visible marks and uneven texture, which reduces the final appearance and quality.
Mix a mild detergent or deck cleaner with warm water in a bucket. Apply the solution generously across the decking. Use the stiff-bristled brush to scrub the boards, focusing on stubborn stains or patches of mould. If using a pressure washer, maintain a safe distance to avoid damaging the wood.
The "30cm decking rule" in the UK is a guideline for permitted development: if your deck is no more than 30cm (about 1 foot) above the ground, covers less than 50% of the garden (with other structures), and isn't in front of the house, it generally doesn't need planning permission. This rule helps determine if a deck is considered a minor improvement (no permission needed) or a significant build (potentially requiring approval), but local rules and exceptions (like listed buildings) can vary, so checking with your local council is always best.
Some of the common reasons that you get a sticky deck is the possibility that the first or second coat could still have been soft or not fully cured. The decking panel could have reached maximum absorption and could not absorb the oil any further causing it to remain at that top.
Drawbacks of Oiling Wood:
* Regular Maintenance: Oiled surfaces may require periodic reapplication to maintain their appearance. * Limited Surface Protection: While it protects against moisture, oiling offers less protection against surface-level scratches and impacts compared to harder finishes.
Cleaning Products You Should Never Use on Wood
Directions
Wood surface must be clean, dry and frost-free with a maximum moisture content of 20% (be cautious with woods with high moisture, such as green oak). Clean or slightly sand old microporous (oil-based) finishes or remove old varnishes and lacquers by sanding.
For cleaning pretty much anything. But it does clean wood furniture, raw wood, or stained wood. Just make sure that you let it dry completely before you do anything to it.
The first step should always be to clean and degrease before you start sanding. If you don't do it in advance, you'll be sanding the grease and dirt into the surface. Obviously, you'll want to avoid that, as it will ruin your hard work.
Without the right deck spacing, the boards may expand, cup, and buckle out of place. As a result, you may have to replace broken decking, or reinstall the boards with wider spacing to prevent further cupping and buckling, which can be time consuming and expensive.
The 2.5-metre rule applies to the maximum height of a garden room when it is built within 2 metres of your property boundary. If your garden space is placed within 2 metres of any boundary (e.g., fences, walls, or hedges), the total height must not exceed 2.5m to qualify as permitted development.
The "3-4-5 rule" in deck building (and construction) is a simple, effective method using the Pythagorean theorem (32+42=523 squared plus 4 squared equals 5 squared32+42=52) to ensure corners are perfectly square (90 degrees). You measure 3 units (feet/inches) along one edge from the corner, 4 units along the adjacent edge from the same corner, and the distance between those two marks should be exactly 5 units; if it isn't, adjust the corner until it is. This creates a precise right angle, essential for stable and professional-looking decks, and works for larger areas by using multiples like 6-8-10 or 9-12-15.
Using warm soapy water and a stiff bristled decking brush, clean any dust or dirt from your timber deck then rinse with a hose and allow to dry. If a deeper clean is required, some flooring manufacturers can recommend an appropriate cleaning solution.
Mildew and Mold Growth
Mildew and mold thrive in damp conditions, and a deck that is not properly sealed can become a breeding ground for these fungi. If you see black spots or green growth on your Merbau decking, it's a clear indication that it needs to be cleaned and refinished to prevent further damage.
October is not automatically too late to stain a deck, but it becomes increasingly risky as the month progresses, requiring specific, ideal weather: mild temperatures (above 50°F/10°C), low humidity, and a solid 2-3 days of no rain for proper drying and curing, which is harder to find in late fall due to morning dew and potential frosts that ruin the finish. If you can't guarantee dry conditions and mild temperatures, waiting until spring is often a better, cheaper, and less frustrating option.
Equipment for Dust-Free Sanding
This isn't good for your sander, sandpaper, or workpiece — and it'll tire you out quickly. Pushing too hard with random orbital sanders can even slow down the rotation of the pad. Hold the sander down with enough pressure to keep it flat, but let the sandpaper do the work.