Merbau deck oiling questions

Hi,

I'm building a deck at the moment, with treated pine bearers/joists and 90mm Merbau decking. I'm going to use spa n deck to oil the Merbau, but I wanted to hear peoples opinions on a few things:

- Do I need to oil the underside and edge of the merbau prior to laying it - and then oil the top side once the merbau has weathered

or

- Don't bother with oiling the underside or edges prior to laying it - and then oil the top side once the merbau has weathered


And finally, should I be oiling any cuts I make for butt joints prior to laying?

Many thanks!

Hi Matterhorn

Not to be picky but spa n deck is a water based acrylic not the same as deck oil nor are the two compatable...

• Doing end joins with spa n deck is a mission as your spose to clean it and wet it prior to applying to get adhesion
• if you were to do ends and got some on the face you would see it when you coat the deck
• you have to apply cleaner to the deck before applying the top coat how will this go with the parts you have already done.. not good
• doing the underside woont happen either for the same reason.. if you washed the boards and followed the instructions... A you would need 3 times the area of your deck to spread it out and B the boards will warp in the sun seeing as you have flooded 1 side and sealed it whilst they are unrestrained
• No need to wait for it to weather unless the boards are really poorly dried and if that is the case buy them elsewhere

Best bet is to build your deck clean it and coat it as per instructions

If you want to apply something to the top of the joists go for it just make sure its not oil base or the spa n deck cleaner will take it off ..which means either spa n deck it or use a joist cover strip

cheers utemad

Hi utemad,

You raise some excellent points. And yes, sorry for the spa n deck and 'oil' confusion :-

What you're suggesting sounds good to me. I think it's going to make the job A LOT harder and more time consuming to coat the underside of each board. The deck is 9 x 5m, so approx 500 l/m of Merbau!
I only asked as friend at work suggested I coat the underside prior to laying, but it doesn't really seem like a common practise, or a very wise thing to do considering the cleaning required before painting the top of the deck.

Thanks again for the reply.

We have pulled apart tonnes of old hardwood decks.. the rot is in the top of the joists caused by the split from the nails and lack of ventialtion to dry out the joist .. the decking does get minor rot where it sits on the joist but the majority of deterioration is from the top side facing up to the weather with a worn or no coating....

to get life out of a deck use treated joists or cover the top of the hardwood one with a joist cover or atlest a couple of coats of stain..
use deck fixings that will hold the boards down properly
Maintain the deck coating

These simple things will extend your deck life more than covering the underside of the decking

cheers utemad

Quote:

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Originally Posted by UteMad

We have pulled apart tonnes of old hardwood decks.. the rot is in the top of the joists caused by the split from the nails and lack of ventialtion to dry out the joist .. the decking does get minor rot where it sits on the joist but the majority of deterioration is from the top side facing up to the weather with a worn or no coating....

to get life out of a deck use treated joists or cover the top of the hardwood one with a joist cover or atlest a couple of coats of stain..
use deck fixings that will hold the boards down properly
Maintain the deck coating

These simple things will extend your deck life more than covering the underside of the decking

cheers utemad

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Great advice, thank you very much.

I'm using treated pine joists, so I should be okay then. Like I said I'm planning on using Spa N Deck, and I'm also using 50mm SS screws for the Merbau. I'm pretty confident this combination should give me years of enjoyment from the deck.

You also mentioned in your first post there's no need to wait for the Merbau to weather before applying the Spa N Deck. Without trying to open a can of worms here, I've read very differing opinions on letting the deck weather or not. Some say not at all, some say 3 months. How do I tell if the boards are poorly dried?

I'm planning on getting the Merbau from Connollys, and the guy there said to also apply the Spa N Deck straight after laying.

I had a spare minute today so have thrown on a demo deck resto using spa n deck for all who might be interested

cheers utemad