# Forum Home Renovation Sub Flooring  laminated bearers

## n0ahz0rk

Hi, 
In the span tables in Staines' Decks & Pergolas construction manual, some of the bearers are listed as (for example) 2/145x45, with a footnote describing this as placing one bearer either side of the post, or laminated together according to A.S. 1684.2. 
Can anyone please elaborate on this process of lamination ?  
I'm planning a low deck, sitting the bearers directly into stirrups, so having one bearer either side of a post will not be an option for me. 
Cheers.

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## cherub65

Just glue and nail two together, (face to face) Have grain in opposing directions, (look at end of timber and have rings in opposite directions)

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## OldBugman

This confused me a bit too, not the process of laminating, by why laminate.
All the beareres in the treated pine are specified to be laminated.
Why use 2x90x45 if you can put in a 230x45, surely that would suffice?

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## n0ahz0rk

> Why use 2x90x45 if you can put in a 230x45, surely that would suffice?

  The hieght of the bearers is my problem.... as I'm building it low to the ground, I've got limitations.

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## dib

I recently did all the bearers for a house nail laminating 90x45.  Didn't glue but that would have been a really good job.  The standard just says you need to use a minimum of 2.8mm nails and they either need to be through nailed and clinched or nailed from both sides.  I had a nail gun and it only took a minute to do each one.  It does also say you can use screws if you want.

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## Stan 101

From memory you will require two rows of of effective stitch nailing at 250mm centres. Stitch nailing is where one nail is angled into the timber and the next nail is angled in at the opposing angle to help avoid creep or movement of the two members. 
An effective lamination transfers the between the two members to have them act as a solid. Not having the members fitted hard together then puts bending force (as opposed to mainly shear) into the nail causing it to be less effective and possibly fail. 
When nailing be sure to keep the nails away from the edge of the timber. This is refered to as an edge distance. As a worst case scenario keep the edge distance to 8 x the diameter of the nail. (5 x diameter is generally accepted for most connections.)  
cheers,

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## dib

I remember now than my chippie told me to angle the nails in opposite directions.  We didnt do two rows but we staggered them (Which is what A.S. 1684.4 says to do)

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## n0ahz0rk

If I was going to use 2 laminated 90x45 bearers, would the span properties of this be different to a 90x90 bearer ? I can't seem to find any mention of 90x90 in Staines' book.

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## dib

AS 1684.4 does not mention it either.  F5 & F7 can use 100 x 75 (90x70), 125 x 75, 150 x 75 etc.  All the mgp 10 stuff is laminated.  It really is very easy to laminate the bearers and probably a bit cheaper than buying the larger dimensions.

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