# Forum Home Renovation Decking  lvl or glulam beam?

## breakerboy2000

which is stronger? what is the difference? my understanding is for lvl the strips are laminated side by side each other, so for a horizontal beam the end grain are on the top and bottom, and glulam, thicker strips of wood are stacked on top of each other, Im wondering which would be stronger for a floor bearer? thanks.

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## phild01

The laminated beam is stronger but more expensive and used when bigger cross-sections are  required.  Generally made from hardwood, rather than the lvl softwood.  Better performance from a laminated beam can be got when using cambered lamination.

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## ringtail

Both are enormously strong and I wouldn't be so quick to say the glu lam is stronger. It probably is and as Phil mentioned, the ability to get them cambered is nice. I guess with any manufactured product it's only as strong as the glue holding it together. It would be interesting to see destructive testing video. The value for money is where LVL's are miles ahead of I reckon.

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## barney118

It all depends on the type of wood used in the beam as lvls generally softwood, glulams can be either (not mixed), you can also get cross banded lvls as special orders. None are recommended for exposed use. download design it from CHH and you can compare sizes for applications.

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## breakerboy2000

Thanks for the replies. I am just getting some ideas for .my future work shed build, Ive been looking at h3 slash pine glulam beam f22, these beams already come with a camber. Now sorry for my lack of knowledge, but this camber is just a very slight bow in the beam, over a 5-6 meter beam would it be noticeable? Will it still sit on the posts flat? These camberes would be used to help counter the weight of dead loads?  Thanks again. 
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## ringtail

Yep, the camber is to support dead certainly and live load depending on the application and is noticeable.You might just have to make the bottom check out in a supporting post on the same camber as the beam. Most guys don't bother though.

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## breakerboy2000

Oh okay, so if I'm going to go for 4 posts across a 6m span with a bearer on top, would I be best trying for a beam with no camber? If there is a camber how will the floor joists sit flat? Seems like the ones in the middle of beam would sit higher  
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## phild01

It is best to use the software like Quick Design to calculate the deflections of the beam. What is noticeable is a deflection of a straight beam under load.  A cambered beam can be calculated to counter the deflection and end up being straight.  Tilling Timbers Smartframe QuickDesign will comprehensively show you differences in use of lvls and laminated beams (cambered or straight).
.

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## METRIX

> Oh okay, so if I'm going to go for 4 posts across a 6m span with a bearer on top, would I be best trying for a beam with no camber? If there is a camber how will the floor joists sit flat? Seems like the ones in the middle of beam would sit higher  
> Sent from my HUAWEI P6-U06 using Tapatalk

  6m span with 4 posts is nothing to worry about.
But you would need to look at what is going on top of the bearer, ie: where is this bearer being used. 
Such as an end or trimmer, an intermediate, undercover, on a deck, supporting load bearing walls, supporting concentrated roof loads, then you can work out what is the most appropriate type and size to use. 
But for calculations sake below is some examples, figures are working to the closest size member available. 
Bearer supporting load bearing walls with 3 continuous spans
Roof dead load 90kg/m2
Wall dead load 35kg/m2
Floor dead load 40kg/m2
Floor point load 1.8kN
Floor live load 1.5kPa
3 spans of 2000
RLW 2400
Wall height 2700
Joist span 3000 
LVL15 
150x42 is loaded to 99% with a 5mm deflection 
LVL18
140x35 loaded to 96% with 6mm deflection 
GL13C
168x55 loaded to 92% 3mm deflection 
GL17C
130x65 loaded to 66% 4mm deflection 
GL18C
150x65 loaded to 46% 2mm deflection  
FYI:  
A LVL15 is made from douglas Fir 
LVL18 is made from Keruing (hardwood) 
GL13,17,18 are made from Pine, with different densities over the various models ranging from 550kg/m3 to 650 kg/m3 
All GL beams have a camber of 600m built into them, you can order non cambered  ones but off the shelf stock is cambered. 
For your 6.0m beam the camber would be  7.5mm

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## phild01

> YI:   
> GL13,17,18 are made from Pine, with different densities over the various models ranging from 550kg/m3 to 650 kg/m3

   The GL18's I got are HW B grade, not pine.

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## breakerboy2000

Thanks for that, this will be roughly a 3x 6m workshop going next to my existing shed, 
Metric, so are you saying if I go non cambered with my post spacing I shouldn't have a problem with bend in the beam? 
What if I over compensate with the non cambered beams, say 290x65, at around 1.5 post spacing surely I wouldn't have a problem with the load bending the beams? 
I was thinking 8 posts in total, 4 on one 3m side, and 4 at 1.5m ( in middle) and the end closest to shed will be fixed with a ledger board. The span tables say only 3 posts would be enough for 6m but if I use 4 I want to make sure non cambered will work, I feel using straight beams will be easier to work with as this is my first shed build.  
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## phild01

You really shouldn't stress about the camber beam.  If you calculate correctly you will likely find the outcome will be good.  The thing with a straight beam is that you need to oversize it to get minimal or no deflection.  The software tells you what deflections to expect with the load design you have.  However, having said this, I did calcs for a 6m span and expected the cambered beam to deflect down below level about 8mm.  It ended up being almost dead straight dropping only a mm.  If I used a straight beam of the same size, I would undoubtedly have had a 10mm dip in the middle.  If you want zero deflection with a straight beam, it will be a much bigger beam and heavy.  Over 6m, the 7-10mm camber really is incidental in the overall scheme of what you are building. 
When on other computer, I can run the figures through the software I have.

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## METRIX

> Thanks for that, this will be roughly a 3x 6m workshop going next to my existing shed, 
> Metric, so are you saying if I go non cambered with my post spacing I shouldn't have a problem with bend in the beam? 
> What if I over compensate with the non cambered beams, say 290x65, at around 1.5 post spacing surely I wouldn't have a problem with the load bending the beams? 
> I was thinking 8 posts in total, 4 on one 3m side, and 4 at 1.5m ( in middle) and the end closest to shed will be fixed with a ledger board. The span tables say only 3 posts would be enough for 6m but if I use 4 I want to make sure non cambered will work, I feel using straight beams will be easier to work with as this is my first shed build.  
> Sent from my HUAWEI P6-U06 using Tapatalk

  What is the load you are expecting to put on the floor, a 290x65 is a massive beam for a simple shed spanning 1.5 posts.
You are overhinking the situation, just go for a LVL, these work perfect for 99% of situations. 
Don't be concerned with a few mm deflection this is normal, I would be concerned if the deflection was 20mm, but if it's only 3-4mm don't worry about it. 
If you can provide a bit more information relating to your build, we can calculate the deflection for your situation.
What is the shed made from, tin walls and roof, Timber walls and tin or tiled roof, if you can put up a sketch of what it is your relating to as well this will help. 
I noticed you have posted your question in the decking section, is this bearer for a deck ? 
If so I would opt for Solid MGP treated pine and they would be doubled up for bearers, or as you are on the Gold Coast they tend to go for Hardwood up their rather than pine.

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## breakerboy2000

I would like to rip out the suspended slab as the timber holding it up it rotted out bad, and the workshop will be there in place of it. 
Over all I would like the foundations, beams and joists all to be super solid with no bouncing etc. 
There will be a few heavy work benches in there along with some w/w machines,  8 posts, 2 bearers and a ledger board with joists on top then a ply floor on top of that, then normal framing for the walls using 90x45 or something, with matching tin sheets for the external lining, the roof will be a flat pitched roof with highest side closest to shed. 
Maybe after its built, down the track I would like to tile the floor, who knows, but I'd like it to be solid enough so I have these options after. 
Thanks for your help guys   
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## METRIX

The timber holding up the suspended slab rotted out ???? Thats deffinetly a strange construction, never seen timber holding up a suspended slab. 
Anyway, what is the final size of the shed, 6m x ???m

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## breakerboy2000

The shed would probably be 5x3m  
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## barney118

I would put in a concrete footing and brick up and fill inside and put a slab down. Alternatively put in some piers , bondeck as sacrificial formwork and slab down.

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## DuckCommander

Just get a non-cambered beam. A continuous cambered beam over a number of supports isn't adding any value to your cause as the bending moments for single span and a continuous span are nothing alike. Deflection of below 1 in 250 will be fine.
Don't read too much into too precise timber loadings and predicted deflections, use them as a plus/minus guide. Timber engineering is far from an accurate science due to the inconsistent nature of timber. Deflection calcs are just a better than pulling a number out of a hat. Immediate deflection is calculated as a standard elastic calculation. As timber 'creeps' (cells deform over time when loaded) it gets worse and this can take 10+ years. The 'accurate' way this long term additional deflection is calculated is simply a doubling of the estimated immediate deflection. So yeah, grain of salt...

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## METRIX

> The shed would probably be 5x3m  
> Sent from my HUAWEI P6-U06 using Tapatalk

  OK 5x3 this is a relatively small shed, fairly simple calculations for this 
A few options based on the following figures 
Roof dead Load 20kg/m2
Wall dead load 35kg/m2
Floor dead load 90kg/m2 (this will allow you to put what you want in there)
Floor point live load 1.8kN
Floor live load 1.5 kPa
Wall Height 2700
RLW 1800
Joist span 3000 
2 continuous span of 2500
LVL15 240x58 rated to 83% deflection 1mm
LVL18 240x45 rated to 67% deflection 1mm 
IF you really want to go to 3 cont spans of 1666
LVL15 170x58 rated to 62% 1mm deflection
LVL18 200x45 rated to 50% 1m deflection 
For your joists rated at floor live load 1.5 kPa and 90kg/m2
LVL15 90x42 spanned at 1500 spacing 450 loaded to 68% 3mm deflection
LVL15 120x42 spanned at 1500 spacing 450 loaded to 31% 1mm deflection 
The choices I would probably go for with your scenarion is 3 spans of 1666, with 2 end bearers and 1 intermediate bearer at 1500 spacing 
For the intermediate bearer use LVL15 170x42 x 2 gives a 40% load and 1mm deflection
For end bearers use LVL15 170x42 43% capacity and 1mm deflection 
The only reason I would choose 3 spans over 2 for your scenario is because you said you want to put some machinery in there, so I have rated the floor to 90kg/m2 instead of 40 or 62 
Don't get too caught up on the deflection, all structures have some movement, you need to allow for something, and for your scenario it is unjustified to try and achieve zero deflection, it is only a 5x3 shed.

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## breakerboy2000

Thanks for the replies guys and thanks metrix for working that out for me, that gives me a good idea. So I'll probably like to go with 3 spans, and your saying  2x 170x 42 for the outside bearer, and 1x 170x42 for the middle bearer? You say 2x for the intermediate bearer? Was this a typo ? 
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## METRIX

> Thanks for the replies guys and thanks metrix for working that out for me, that gives me a good idea. So I'll probably like to go with 3 spans, and your saying  2x 170x 42 for the outside bearer, and 1x 170x42 for the middle bearer? You say 2x for the intermediate bearer? Was this a typo ? 
> Sent from my HUAWEI P6-U06 using Tapatalk

  Yes two bearers for the intermediate is correct, this will achieve what you want.
Putting doubled up bearers as all your intermediate is fairly normal, we do it for all our construction unless using steel or the engineer has stipulated something else. 
You need to remember the intermediate bearers are being loaded from both sides so they will take double the floor load, end beares are only loaded from one side (but usually a wall is also added to end ones so this needs to be taken into considertion) 
Rather than changing the dimensions of the internal bearer, it is easier to keep the size the same and double them up (if the calculations agree). 
To answer your question, Intermediate bearers are anything that is not on the edge, so 1 x bearer for the outside, and double up the centre bearer
Also make sure if your using LVL the perimiter bearers do not get exposed to the weather, they are not designed for this abd will eventually cause you some problems, you need to protect the top and sides from exposure.  *Bear in mind you shoud not rely solely on a forum to give you the  correct information, 
you should seek the advice of a licensed builder in  your local area or engineer to confirm the calculations are correct.* 
Below is a picture from another posting, you will see the doubled intermediate bearers we used for this deck extension.

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## breakerboy2000

Im drifting a bit, but when you double them, can you either notch the post out on both sides to house the bearers with a gap in between, or
 notch out on one side of post, and nail bearers directly to each other?

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## METRIX

Correct we notch around 15mm from both sides of the post, then bolt them together with M12 bolts through the post

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## shauck

and you can block between the bearers at intervals

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## METRIX

> Im drifting a bit, but when you double them, can you either notch the post out on both sides to house the bearers with a gap in between, or
>  notch out on one side of post, and nail bearers directly to each other?

  I prefer to notch both sides rather than one side only, this gives both bearers a shoulder to sit on and keeps the load even on the post, if you put the two bearers on one side you are putting all the load onto one side of the post, not that this is a major problem I just prefer the load to be centered over the post. 
And as Shauck said block the bearers out between the post spans and throw a bolt through this point.

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## breakerboy2000

No worries, in your calculations metric, you've rated the floor at 90kg/m2, I was thinking of having a ledger board in place of the third bearer instead of putting posts so close to the existing shed. Is there a point where a ledger is not to be used? As the floor is rated 90kg, will putting a ledger board in reduce this rating? 
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## breakerboy2000

> The timber holding up the suspended slab rotted out ???? Thats deffinetly a strange construction, never seen timber holding up a suspended slab.

  Just thought I'd put the pic of the under side, that front beam is completely gone and is not doing anything. Can't wait to get rid of the lot         
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## DuckCommander

> Just thought I'd put the pic of the under side, that front beam is completely gone and is not doing anything. Can't wait to get rid of the lot     
> Sent from my HUAWEI P6-U06 using Tapatalk

  Pretty special setup you've got there

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## METRIX

Can't say I have seen a setup like that before  :Eek:

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## ringtail

Wow, thats special

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## goldie1

How has that slab been poured ???  Is that compressed sheet on top of the joists?

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## paddyjoy

Excuse my ignorance but wasn't it pretty standard to do this back in the good old days, laying slabs on joists for bathrooms and kitchens?

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## goldie1

It was but not outdoors usually with corro  over the joists

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## breakerboy2000

Yes it has compressed sheet , paddy I'm not sure if they did full 90-100mm slabs Like this or just 40-50mm mortar beds, I'm not sure how suspended slabs are ment to be built don't think like this way, the previous owner did a bit of stuff around the house , apart from this most seems like decent work , although apparently he did our patio roof, which has about 0-1 deg pitch :/ 
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## goldie1

> Yes it has compressed sheet , 
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  Asbestos no doubt

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## goldie1

> Yes it has compressed sheet , paddy I'm not sure if they did full 90-100mm slabs Like this or just 40-50mm mortar beds, I'm not sure how suspended slabs are ment to be built don't think like this way, the previous owner did a bit of stuff around the house , apart from this most seems like decent work , although apparently he did our patio roof, which has about 0-1 deg pitch :/ 
> Sent from my HUAWEI P6-U06 using Tapatalk

  Plenty of bathrooms done like this.  Corro laid over the joists then slab poured. Never seen one out doors 
like yours

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## paddyjoy

> Plenty of bathrooms done like this.  Corro laid over the joists then slab poured. Never seen one out doors 
> like yours

  Actually yes I think from memory my bathroom slab does have corro underneath.

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## barney118

I would cut the old slab out and use it for fill, retain the area backfill with broken slab and pour new. trying to fix something like this could go any way you probaly dont need a lvl or such put some more post directly to the slab. the issue is there any reo in the slab as it probaly ok as a suspended slab but is it worth the risk?

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## breakerboy2000

> I would cut the old slab out and use it for fill, retain the area backfill with broken slab and pour new. trying to fix something like this could go any way you probaly dont need a lvl or such put some more post directly to the slab. the issue is there any reo in the slab as it probaly ok as a suspended slab but is it worth the risk?

  well my plan was not to repair this but completely remove it and build a timber floor,(posts on footings, bearers, joists and plyfloor) 
your idea with a retaining wall and a slab floor seems more suited for a workshop though, I would probably have to get somone in for this if i went that way, could be quite costly?. would definitely simplify the whole build.

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## barney118

> well my plan was not to repair this but completely remove it and build a timber floor,(posts on footings, bearers, joists and plyfloor) 
> your idea with a retaining wall and a slab floor seems more suited for a workshop though, I would probably have to get somone in for this if i went that way, could be quite costly?. would definitely simplify the whole build.

  its not a big area, TP sleeper retaining wall is cheap allow you to go a bit wider 200x75 post spaced at 1200 at least 600 in the ground concreted, ag pipe at base of wall, fill the hole with old concrete etc with gravel and dust to the top 50-100mm pack it and new slab. at least peace of mind rater than try and save something that looks a bit dodgy to start with and spending $ on the top only for you to worry about the base.

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## breakerboy2000

hey barny, would you know a ball park figure concrete guys would charge for somthing like you say?
im trying to compare costs using timber frame vs concrete base. i have seen slabs that arnt suspended, but they are about 1-1.5m off ground and have besser block walls and are just filled in, is there a special name for these types? 
thanks.

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## barney118

You could do most of it yourself, break up the slab put it in the middle, dig a footing around outside probably 450 wide by 350-500 deep. Engineer $200 for footing info, excavation 4 hrs should do the job $90 hr, prob $500 brickie plus bricks. Concrete yourself prob only 2 m3 all estimated   
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