Thread: Merbau Deck Finish

Don't know about the rest of the stuff as I'm a newbee looking around to work out what I do with my deck but I can at least tell you that tannins aren't toxic - at least I hope not because the tea I'm drinking now is full of it as was the vegies I had for lunch and the fruit for breaky (and so people don't think that I'm a total health freak - the chocolate I have later will have it also). The astrigent flavour you get in some foods (particularly unripe ones) is tannin. I think they're antioxidants - though I don't suggest you try to eat the merbau for it's life preserving properties. A down side - my girlfriend was recently told not to drink tea because the tannin binds iron - but that's a long way from toxic.

On the subject of tannin, there are lots of different chemicals that are described as tannin. The tannin in tea is obviously quite different to the tannin in Merbau. I wouldn't recommend brewing up a handful of offcuts, it wont taste very nice. It probably wont kill you, although some tannins are toxic in high doses apparently.

On the subject of weathering, well as I've said elsewhere, I left mine for 6 months or more and it was quite grey. I cleaned it up with a high pressure washer to remove the dirt and then oiled it. It looked brand new. Some people wash them with various washes and cleaners but I was happy enough with the condition of the boards after a wash down with water alone.

I don't know what, if any, affect salt water will have on merbau. My guess is none but it may affect the finish you use, so make sure that what you buy is suitable for salt water exposure, although the level of salt in a swiming pool is not that high and it's probably better than a chlorine pool.

As for removing the tannin stain from concrete and steel, I guess it will fade over time. I have stains all over the steel sub floor of my verandahs but that will disappear when I paint it (one of these days). I have noticed it has faded. Likewise on the concrete pads. But there will still be a brownish smudge. Maybe some sort of cleaner or bleach will remove it? Never bothered to try.

Thanks Guys,

think i will skip the Merbau tea for now
I dont mind waiting 6 months - got other things to do now anyway - just want to make sure im not "over" waiting. particularly since the pool washes it down daily ATM.
May try bleach or Acid to remove the stain - its between the deck and stone pool coping mortar jointsand looks crap!

richo

When i idd my merbau deck a few years ago, the timber had been stored outside and the tannin crystalised on it. I hosed most of the boards to get some of it off, before laying (after drying in the summer heat)

Once laid a few weeks later i used Cabots deck clean. lifted eth rest of eth tannin and the build up of dirt. Haven't had a problem.

I think the idea of "weathering" is for the tannin to leach out. the downside is the timber also greys. the idea of all the cleaners is to overcome this. the bottom of most decks are unsealed, so i suppose than tannin willl leach out there.

Bondall, makers of Bondcrete, make a Bore, Rust, & Tannin remover, could email them for a MSDS to see what the active ingredient is.


Cheers.................Sean

I've used Merbau on a number of decks and greying will occur with moderate weathering within about 3 months. I've used woodmans woodwash then a few coats of Sikkens cetol deck will get the colour back into it. Intergrain have a new water based product called Ultradeck which is designed to last a little longer than standard decking finishes.

Cheers.

There has been quite a lot of discussion on the thread of cleaning timber,allowing it to weather to allow the tannins and oils to leach out. I tend to follow the guidelines that most coating manufacturers state in their literature and let a new deck weather 3-4 months and then clean it with a cleaner before coating. Merbau is regarded as one of the timbers that really bleeds when wet. I have finally figured out how to get my photos from my camera to the attachment section of the posting page. Almost as good of feeling as finishing off a big deck. The photos that I have posted for anyones interest only is of a merbau deck that had been coated with an oil based decking stain. The deck and its coating was about three years old.

Picture 1 Shows the deck before removing the coating. I removed the coating by sanding.

Picture 2 Shows the deck during the cleaning stage. The bucket in the middle is the oil and dirt that was brought to the surface by the detergent and collected from the surface by a scrubbing machine. To the right of the bucket it shows the oil collected and the timber clean and to the left of the bucket the oil on the deck before the collection. One of the things I find amazing is just how much of the oils remain in a timber deck that has been exposed to intense heat and sun over a number of years. I would agree that the oil based stain would have held it in but the stain was removed by sanding before the cleaner went on.

Picture 3 Is the deck with three coats of Spa&Deck cedar in colour

I have discovered that every deck that I clean will offer a large amount of oil and dirt that when collected into a bucket looks as black as sump oil with the merbau timber being a very dark blood colour.

I have posted the photos for interest sake only and hopefully allow people too see what the cleaning process can achieve.

This is something I often wonder about. In order to sand a deck, you must punch the nails, correct? Yet a lot of people say you shouldn't allow the head of the nail to penetrate below the surface of the timber so that you don't get water sitting in there, which can lead to black stains and water damage. How do you get around that? Do you fill the holes?

Thanks for the question. The issue of the correct nail that should be used generally brings up an entirely new heated discussion / debate. The nail that is recommended for 19mm decking in Qld is the 50mm/2.8gbullet head nail predrilled and hand nailed to be flush with the surface. I guess in an ideal world that would be great but I find where I live along the Sunshine coast 75% of the decks are dome headed nails. The builder is happy because he can put them in with a nail gun and then the first coat of decking product goes on easily as there is no product in the road. I seem to get called to mainly 3-4 year old decks where the coating is giving up. Now some coatings can be cleaned up with a detergent, waterblast and scrub where others can't and the only option is to sand. You can't sand off the tops of the nails as it ruins both the nails and your sanding equipment. The only way that I have figured out to solve the problem is to get the nail below the surface. If anyone knows another technique I would like to hear about it. Yes ,it leaves a hole for water to sit in but the time it is goiing to take to rot out the timber will be some time down the line if ever and the people I work for are informed of this issue. I havn't had one person who cares they just want their deck to be brought back to something they are happy with and can maintain with a very user friendly product. The other thing that happens is the small holes tend to collect a small amount of the product inside the walls of the hole offering some protection to the timber and the nail. I can assure you that when I show up to have a look at a deck I have my fingers crossed that it won't be a dome headed nail that needs punching down as there is no joy or fun being on your knees for the day punching nails on a stinking hot day in Qld. This whole timber decking story is full of pros and cons and we all have to weigh up the issues and make the choices we can be happy with.

Merbau deck

My apoligies for not correctly answering your question. Not I don't fill the holes at all. I enjoy restoring decks but not that much!

Not trying to hijack the thread but I too have been reading all the deck threads with interest. I am going to be constructing two decks in the near future on a new house, going to use Blackbutt for the flooring.
Just wanted to ask Jim if he has used Spa and Deck on this timber and what colour would be the most suitable. From what I have read in this thread I should not use a dome head nail but rather a bullet head that finishes flush with the surface. I was planning on gun nailing the decking so may have to re think this one.

Cheers

Fair enough, I just wondered. I've heard of people punching the nails and then sanding the whole thing with a floor sander before the first coating ever goes on. I'm sure it looks great and I wish I'd done the same. Was just curious about the nails and what you had found to be the consequences of punching them.

I don't suppose it's any different to what they do with an internal floor, but if you used a filler it would have to be suitable for external applications.

I laid mine with a gun and it's nigh impossible to get the nail heads to seat consistently with that method because of the vagueries of timber density and compressor pressure. Some of mine are below, some flush. The ones that were proud got hit with a hammer.

Dear Sleeping -Wood

Thanks for the question . I havn't come across a Blackbutt deck as of yet. The most common are Merbau,Spotted gum, Ironbark and the smorgasboard of timbers called mixed Australian hardwood. On probably 90% of the decks that I coat the customer picks cedar. However in saying that as Blackbutt is a very light coloured timber I would say that cedar is too orange and would not be that pleasing. Don't even consider natural unless you want a very yellowy looking deck. Redwood would I think be way to red so that leaves Sedona which is a closer to a walnut brown type of colouring. I just did a yellow balu front entry and we started with the first two coats with cedar to see how orange it would be. It was a little more orange for the customer than they wanted so we next coated it with two coats of sedona. The brown tint toned down the orange and the outcome was a very pleasing colour. The beauty of the Spa&deck is that you can play around and blend colours. I have done several similar blends on treated pine decking. I would contact Flood in Sydney on their toll free number and see if they can send you some sample of cedar,sedona and natural and then try different coats on some small timber off cuts. The coating touch dries quickly and different coats can be added after several hours. If you strike a colour combination of say 25%cedar and 75% sedona you can either blend those ratios together in a paint can or achieve the look by applying the different colours one coat at a time. Remember the first coat of Spa&Deck is applied to wet timber so in effect it really represents a half coat. If your deck is under protection then three coats is fine. If it is totally or mostly in the sun and elements I would highly recommend 4 coats.

You can get more info from www.floodaustralia.net
and no I don't work for Flood but their customer service both in the office and in the field (in my opinion) is outstanding. I am having great results for the customer with the product and will continue to use it until something gives a better result in both the short term and in its longevity.

I hope this reply will give you something to work on.

Goodluck!

Jimj Not sure if you want to see my web site but it has 15 before and after photos of different decks with S&D. I have another 6 to go on line with soon.www.restore-a-deck.com.au

Originally Posted by sleeping-wood

From what I have read in this thread I should not use a dome head nail but rather a bullet head that finishes flush with the surface. I was planning on gun nailing the decking so may have to re think this one.

Have you considered hidden deck fasteners? No nail heads to set (or reset), aesthetically pleasing. Most all new decks here are going this way because of ease of maintenance and looks. There are several different kinds available.

And Jimj, are hidden deck fasteners growing in popularity in OZ or not considered by most homeowners?