Thread: Treated pine or Hardwood Merbou? Which is better for pergola?

Both have pros and cons. Hardwood will give you greater spans for a given size but will stain concrete and brickwork. Also dearer than treated pine. LOSP treated pine is ok above ground and resists surface cracking which can be a problem with CCA treated pine. If there is going to be ground contact the timber needs to be class1 hardwood or CCA treated.
Hope this helps.

G'Day & Welcome to the forum "Chandani",
I'd use an Australia plantation hardwood over treated pine for durability.
You'll have to do some leg work to fine a good supplier at a fair price.
Make sure you shiow off your handiwork as everyone loves photos.
Cheers, crowie

Originally Posted by rustynail

Both have pros and cons. Hardwood will give you greater spans for a given size but will stain concrete and brickwork. Also dearer than treated pine. LOSP treated pine is ok above ground and resists surface cracking which can be a problem with CCA treated pine. If there is going to be ground contact the timber needs to be class1 hardwood or CCA treated.
Hope this helps.

Thanks Crowie. I am thinking of Merbau or maybe Jarrah. Will that be ok?

Originally Posted by Chandani

Thanks Crowie. I am thinking of Merbau or maybe Jarrah. Will that be ok?

Thanks for the tip Rustynail. Our pergola will be above ground.The ground contact may be the posts holding the pergola.

Good Morning Chandani

Firstly, welcome to the forum. You will, over the years, be amazed at the depth of insights offered to members - from very basic to extremely highly skilled. Remember, the only stupid question is the one that you do not ask. Better to learn from other peoples mistakes......

I think it is always a good idea to set pergolas on stirrups to eliminate direct contact with the ground. Having done that, I very much prefer merbau, aka kwila, and it has excellent outdoor properties, is readily available and relatively inexpensive. It is hard and heavy so working is a little harder than pine. The only real downsides are:

* It bleeds a redish stain copiously when wetted. Keep it well painted.

* Marine borers love it, but you are unlikely to take your pergola to sea...

Fair Winds

Graeme

Thanks Graeme for the welcome. I do feel like a novice amongst all of you. Do we paint Merbou or are we required to oil it? Thanks C

G'Day "Chandani",
I've got a small Merbau deck near our above ground pool and what a red mess underneath it, even with regular oiling.
Have a look at some of the Aussie hardwoods, from memory they are also cheaper than the fully imported Merbau.
Cheers, crowie

Another feature of Merbau which is not commonly brought up by the sellers of the stuff in Australia is that it is an old-growth lowland tropical rainforest tree that grows on swampy ground such as the margins of mangroves. It is slow growing and, on the whole, not harvested sustainably. I am not going to tell you not to choose to buy it but there are multiple sources of info on the web about why it as consumers we should not be choosing it as a material. Of course if you can source some second hand that's another matter

Originally Posted by pampelmuse

Another feature of Merbau which is not commonly brought up by the sellers of the stuff in Australia is that it is an old-growth lowland tropical rainforest tree that grows on swampy ground such as the margins of mangroves. It is slow growing and, on the whole, not harvested sustainably. I am not going to tell you not to choose to buy it but there are multiple sources of info on the web about why it as consumers we should not be choosing it as a material. Of course if you can source some second hand that's another matter

Not necessarily completely accurate.

Years ago, I was involved with three forestry companies in PNG and we harvested thousands of cubic metres of kwila, as merbau was universally known in PNG, and none of that was harvested from swamps - how do you operate a snigger in a swamp?

Kwila is not slow growing and we also planted thousands of hectares of kwila plantation in the Gogol near Madang and also in West New Britain. Much kwila is now sourced from such plantations.

But there is also much kwila sourced from Indonesia, Malaysia and PNG that is "unsustainably harvested" as forest is converted to oil palm, cattle runs, rice paddies/paddocks and forestry plantations. Whilst we can lament those forests being cleared, the timber is a by-product of the clearing process and it seems more sustainable to use it than burn it.

Fair Winds

Graeme

Graeme, Having never seen the living tree I cannot really accurately state what it's habitat is, I can only go off literature or web info. Based on your statements you would seem to have more first-hand experience than me in the species. However as you say the timber can come from a variety of sources some of which create more negative outcomes than others. I guess this is the basis of a quite reasonable philisophical argument that being an 'ethical' consumer is really a nonsensical position to take as one can never have all the facts about the impacts of any product one happens to be buying, particulalry in light of what the majority of other people/nations, happen to choose to do. The majority of what is available as secondary source info on the web would suggest that (a) logging (whether it is legal or illegal) is making the species critically endangered, (b) that the trees are slow to mature (some state ~80years in native forest), and (c) that it is very difficult to determine the source of the timber. I would be surprised if the plantation grown material is available in anywhere near the amounts required to satisfy demand, even if it a relatively fast growing plantation species. (Also if any plantation material has come to maturity does it have the same favoured characteristics as old growth timber?)

In any case it is best to aware of the possible consequences of being part of a market for a product. Whether your personal decision to buy or not to buy makes any difference to the people or environment from where the resource derives is a moot point. (e.g. maybe oil palm plantations are a greater contributor to the species decline than logging per se). Just sayin'.... better to be slightly better informed than completely naive.

Originally Posted by Chandani

Hello,

We need advice from the experts! We are planning to make a new pergola. Around 7.5 x 4 dimensions.

We are confused about what wood to choose for the pergola/deck. Should we use Hardwood / Merbou or Treated Pine? What are the pros and cons of these two types of woods? Some contractors say go for treated pine and some say Hardwood is better. We are really confused.

And what should we expect as an approximate cost for using either of these wood types?

Thanks for your help.






C

90 x 22 Premium grade (knot free, all 100% straight grain) pine losp treated is the cheapest at $3-49 Lm, All your Australian hardwoods will leach a stain and if you have concrete / pavers under or adjacent to the deck, it will be ugly, turns black and almost impossible to get rid of it. Merbou leaches badly.
Pelawan is an imported hardwood and does not leach regardless how much it gets wet. 140 x 25 finish DAR depending on your supplier and quantity between $9-00 Lm and $11-00 Lm
Merbou 140 x 25 $13-34 Lm

Use stainless steel screws
90 x 22 boards use 8-10 x 50mm
140 x 25 boards use 1-14 x 65 bugle (batten) screws
H3 pine for joists with Protect-a-deck between boards and joists, the joists will never rot.

Originally Posted by pampelmuse

Graeme, Having never seen the living tree I cannot really accurately state what it's habitat is, I can only go off literature or web info. Based on your statements you would seem to have more first-hand experience than me in the species. However as you say the timber can come from a variety of sources some of which create more negative outcomes than others. I guess this is the basis of a quite reasonable philisophical argument that being an 'ethical' consumer is really a nonsensical position to take as one can never have all the facts about the impacts of any product one happens to be buying, particulalry in light of what the majority of other people/nations, happen to choose to do. The majority of what is available as secondary source info on the web would suggest that (a) logging (whether it is legal or illegal) is making the species critically endangered, (b) that the trees are slow to mature (some state ~80years in native forest), and (c) that it is very difficult to determine the source of the timber. I would be surprised if the plantation grown material is available in anywhere near the amounts required to satisfy demand, even if it a relatively fast growing plantation species. (Also if any plantation material has come to maturity does it have the same favoured characteristics as old growth timber?)

In any case it is best to aware of the possible consequences of being part of a market for a product. Whether your personal decision to buy or not to buy makes any difference to the people or environment from where the resource derives is a moot point. (e.g. maybe oil palm plantations are a greater contributor to the species decline than logging per se). Just sayin'.... better to be slightly better informed than completely naive.

Good Morning Pampelmuse

Whilst I may have come on a little strong, it is obvious that your heart is in the right place. The economies to the north, often trivialised as basket cases, need all the help that they can get. Boycotting their products merely condemns them to their basket case situation - they need trade, not aid. I do get annoyed when well meaning individuals white ant their efforts without realising the consequences.

Most of the kwila outdoor furniture marketed in Australia is sourced from plantation grown timber. It is slightly less red, has wider growth rings and generally has less complex grain patterns, than forest grown kwila - these are generalisations and are influenced by microclimate, geology, soil conditions, etc.

With kwila and kamarere (E deglupta) we were getting broad acre growth rates of 25 m3 per hectare per year - teak was a little slower - ipl ipl was a lot faster. By comparison, few areas of natural forest yielded more than 100 m3 per hectare combined saw and chiplogs, so plantation was very productive, but the timber quality was almost always lower than forest timber because of the growth rates.

Personally, I think it is very important that in attacking the pirates we do not undermine the legitimate individuals attempting to look after their families.

We might think a forest looks prettier than an oil palm plantation, but a small holder can produce 30 tonnes of oil palm fruit each year from a hectare of land. Four or five hectares will give his family a very good income. This is harsh real politics.

Fair Winds

Graeme

There seems to be a mixed opinion about the use of Merbou because of the red colour coming out all the time. Any other hardwood which you would recommend for this project?

Many thanks for the info.