sandwiching lvl for bearers

[gg23]

hi all,
I have a 6.6 x 360 x 45 piece of lvl that i intend to cut to make two 6.6 x 140 x 45 pieces that I will sandwich to make a bearer that is 6.6 x 140 x 90.

My questions are:
1. Can I use a circular saw with a guide to cut the beam?
2. Is there any recommended way to sandwich the two pieces? Glue, nails, etc?
3. with the two pieces sandwiched there will be a small groove on top and bottom of the combined beam as the corners of the wood are slightly rounded. Should this be shaved smooth? Will it trap water if I dont?
4. Also what is the recommended way to insulate the floor whilst it is being built.
Thanks
Greg

[silentC]

Check page 4 and 5 of this document: http://www.chhfuturebuild.com/uploads/Hyspan_SpanTables_Mch06.pdf

[MrFixIt]

hi all,
I have a 6.6 x 360 x 45 piece of lvl that i intend to cut to make two 6.6 x 140 x 45 pieces that I will sandwich to make a bearer that is 6.6 x 140 x 90.

Unless you NEED to have the beam this height, ie 140mm DON'T cut it, as it is MUCH stronger at 360mm high than two at 140mm.

[gg23]

Check page 4 and 5 of this document: http://www.chhfuturebuild.com/uploads/Hyspan_SpanTables_Mch06.pdf

thank you. This is an excellent resource. Not sure what elastometric adhesive is, Aquadhere??

Thanks again
greg

[gg23]

I have to have bearers of 140, and then joists of 90. Btw the engineers recommended joist of 95 x 45 F17, but I am unable to find this dimension. Can I use 90 x 45 F17?

Thanks
greg

[silentC]

You'd have to ask the engineers that. 95 seems an odd size for hardwood though - my span tables list either 100m or 90mm depending on the span/rating. My joists are 95mm but they're LVL.

[gg23]

Hi,
Will be using f17 for the joists even though the engineers specs ask for 95 x 45 LVL, as it is cheaper. Have cleared the substitution with the engineer. Just need to sort out the size. So i guess to be on the safe side, I should use 100 x 45 F17 for the joists. On another note Ive read somewhere that you can cut grooves in lvl bearers as long as they are not greater than 25mm (from memory). Is this really ok? Doesnt it weaken the bearer? I ask this as we have made an error with the stump heights and therefore our floor will sit about 3cm higher than originally planned.

Thanks again for your help, this site is a godsend,
greg :)

[silentC]

Again, I'd run that past the engineer - it is his backside on the line if it fails.

Regarding the joists, if you tell me the span, I can look it up in the tables - they're NSW tables but based on Australian Standards so should be OK (I think Reservoir is in Vic.).

[gg23]

hi silentC
The joists span 3.8 metres, across 3 stumps. Maybe I'll leave the bearers alone.

greg

[silentC]

What you need to tell me is the widest span that a joist has to cover between bearers. For example, if by the above you mean that you have three bearers evenly spaced at 1.9 metres, then the joist span is 1.9 metres: my table says that for up to 2.1 continuous span you can use 90x45 F17 seasoned timber joists at 450 or 600 centres. Continuous span means that the joist spans at least 3 bearers, which I gather it does in your case.

[gg23]

hi silentC,
The you are correct in that the joist span is 1.9m, but the plan from the engineer states that the joists must be continuous. I assume this means that the joists must be 3.8m. Does this change the info that you have given me? Also do you know what KD hardwood rated at?
greg

[silentC]

the plan from the engineer states that the joists must be continuous. I assume this means that the joists must be 3.8m
True. The sizes I gave you are from the table for continuous spans, so that's what you should use.


do you know what KD hardwood rated at?
It should be F17 but best to tell the timber yard that's what you want when you order.

[gg23]

i am considering buying the KD Hardwood from a builder who is no longer intending on using it. He states that it is not stamped, but was purchased with the same intention, ie for joists.

thanks again for your help,
greg

[silentC]

I can't really give you any advice on what to do there. I'd probably speak to the engineer.

[gg23]

spoke to the engineer. Said it was fine as long as it is f17 KD hardwood? In a bind as the price is great, the seller reckons it should be fine, but dont want any hassles with the inspector. What to do?

greg

[silentC]

Well, you could speak to the inspector about it, but if you do, then there's no turning back. He'll make a note to check it.

The only advice I can give is that sometimes it's better not to take the cheap option and sleep better. There's enough that can go wrong in building a house as it is. So you have to ask is it worth saving a few hundred bucks, which in the scheme of things isn't very much?

[gg23]

is it possible to get wood tested for its rating?