The Process for Decks and Timber

When it comes to cleaning decks, fences, retaining walls, cedar cladding, patios, concrete paths and driveways, there is really only one thing that I have learned over the last 20 odd years – no two jobs are the same! Just when I think I have seen it all something new will come along.

What this means is that a “Process” that is applied to every job is really important. Our process:

1. Survey, inspection & measure
2. Cleaning and pH Balancing
3. Repairs and repeat step 2 if required
4. Sealing and Staining
5. Ongoing Maintenance Programme

Each step in this process has several parts to it as outlined below;

1. Survey, inspection & measure – This is quite self explanatory. We inspect every job prior to quoting which 99% of the time means no surprises for us or you. Occasionally we uncover some serious damage which is not visible prior to cleaning.

2. Cleaning and pH Balancing – Probably the most important part of the process. We generally start with a cleaner that is a “Green” non-toxic biodegradable solution that is actually good for the soil. This is sprayed onto the timber and left for 15 minutes during which it will “bubble”.

While it is bubbling we will also use a deck brush to scrub decks, but not any vertical surfaces and especially not cedar. As the cleaning solution is a base, the timber is now quite alkaline.

The next step is to use a pressure washer at less than 600 psi to wash the timber. This step is critical as it is what removes the bulk of the damaged surface, dirt, moss, mould, mildew and the cleaning solution, BUT it is also when serious damage to timber, particularly decks and cedar, can occur. We use only electric pressure washers that are configured to the specialist requirements that working on timber requires. This is generally the slowest part of the entire process.

Next we spray the deck with a timber brightener that is used primarily as a Neutraliser to get the pH of the timber back to slightly acidic, the optimum pH level for the stain to be absorbed into the timber.

For kwila decks we will often spray the deck with a second coating of brightener to remove any remaining tannin stains, and repeat the rinsing.

3. Repairs – Step 3 involves a detailed inspection of the timber. If there are any issues we would normally have spotted them in the cleaning process, but occasionally something becomes visible only after the timber is cleaned and dry.

The most common repair we make at this stage is replacing damaged deck boards, usually in a treated pine deck which has knots that have cracked and are now dangerous as both trip hazards and as a source of splinters. This is not difficult but can take a little time.

Other common repairs are to wooden stairs and baulustrades. If any additional work is completed it means that the deck will have accumulated some dirt and dust so we wash off the deck again to ensure that no dirt, dust, bird droppings, etc are under the sealer and stain.

4. Sealing & Staining – Next we allow at least 2 full days for the timber to dry. The weather can interfere at this point, but almost always there is the 4 dry days in a row required not to far away. Once the timber is dry, then we seal and stain the timber. This generally is 2 days, one to apply the stain and one for it to dry.

Prior to this the owner will have decided on what “look” they want from the finish, and that is no easy decision as there are dozens of options. Our recommendation is almost always a high quality penetrating stain that does NOT leave a surface coating, in a standard colour as this allows for easy top-up coats or easily matched repairs to scratches from moving furniture around.

5. Ongoing Maintenance Programme – At this point the deck is ready to be used, fences and retaining walls can have landscaping or planting completed and cedar is looking fantastic.

But, like rust, the weather never sleeps and your awesome looking timber will quickly deteriorate if it is not looked after, so establishing a maintenance plan is a very good idea.

Generally a deck will need a wash (a much quicker and cheaper version of a full clean) and a top-up coat of stain after about six months and the same again annually from then on.

Cedar may or may not need a 6 month stain top-up, but will definitely need one after about 2 years. All vertical services (fences, retaining walls and building cladding) benefit greatly from an annual wash. As every property is different each maintenance plan needs to be tailored to the individual situation.

Although the process is applied to all the work we do, every job is different. If you would like us to have a look at your timber please feel free to call or e-mail Grant to arrange a time to have a look. Call Grant directly on 021 280-4579 or e-mail