Oriented Strand Board (OSB)

[forumfrenzy]

hello everyone

i have been researching the new material OSB which is big internationally in America and Japan etc however relatviely new in australia. therefore the are no australian standards regarding OSB. therefore im posting the question....

to ensure the OSB passes the building code,
what standards are you ment to follow to ensure it is approved by the BCA,
more specifically how do you calculate certain properties such as the second moment of area I.....

any help would be greatly appreciate

[old pete]

Hi Forum Frenzy,

More than 10 years ago I over sighted a significant research effort to test if Tasmanian hardwood could be used successfully to manufacture OSB.

You are correct that there are no AS to measure OSB against. In the absence of a specific OSB standard we used the standards applicable to construction ply of equivalent thickness.

We tested plantation hardwood , regrowth hardwood and old growth hardwood of pulpwood quality material. Each of those three materials produced a dark dense board that far exceeded the construction ply standard in every criteria excepting the two hour boil test. ( this test is an accelerated means of testing the propensity of the material to de-laminate in service. Many would argue that it does not represent a fair test of product in service in any construction conditions and that is certainly the case but I guess in measuring relativity as in this case it has some form of validity however flawed it might be)

The catch with australian hardwood OSB is that it needs three to five times the amount of resin to get an equivalent bond as is achieved in USA OSB that uses feedstock such as aspen and poplar that is both low density and very receptive to bonding due to its cellular structure. There wasn't a significant degree of difference in the amount of resin required to bond each of the three feed stock types in spite of some pre- conceptions in this area. We found that we could meet the requirements of the boil test by using resin at levels up to 15% dry on dry of the finished board mass. Resin is expensive and given that the US product uses about 3.5% to get to the same place it just wasn't financially feasible to pursue the manufacture of the product in Oz.

A few other issues. An entry level OSB plant needs to have a production level of about a min. of 500 000 tpa to make the financial grade. For a relatively small additional capital outlay that can be raised to 1M tpa with a much lower resultant unit production cost. Production levels like this would predicate almost all production in OZ being exported across the world and that's a freight cost the product simply can't stand. In USA OSB is made from a very cheap low grade feedstock that no one wants for anything else. The product simply can't stand our pulpwood prices. The board produced from OZ hardwood is a pretty horrid product to handle compared to the USA product. It's dark its dense and its very sharp and splintery on the edges none of which attributes are found in the board of the competition over there. There is no culture of building homes in OZ the way OSB is used in this application in North America. It would require a huge cultural leap to effect those changes.

I am reminded of the words of wisdom offered to me by the development manager of one of the biggest OSB manufacturers in US ( and there's only a handful). He said

" OSB is a sh..t product that is made from a sh..t feedstock that is bought for #### prices that then on sells as a board for more sh...t prices to go into a sh..t application and if you get any one of those wrong then you will be in the SH..T financially!!!

The research findings on OSB manufacture from Tasmanian hardwoods are public domain except for some info on use of alternative resins that remains C in C.

PM me if you want more info.


Old Pete

[beer is good]

Thanks for that excellent summary Old Pete. I have seen OSB used in the UK on the TV series Grand Designs and thought it looked interesting and thought of lining my shed with it.

Now I understand why we can't make it here. I believe there is a company here who import it from Germany but it's bound to be very costly.

[Master Splinter]

OSB - Speciality Panels - Building Products, MDF, Plywood & Benchtop Surface Materials - Gunnersens Australia

Available in 9.5, 11, 15 and 18.5mm thickness. On the shelves (ok, wood racks) in my local Bunnies for bracing wall frames.