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View Full Version : Floor load width just means bearer spacing?



camy18
8th Sep 2011, 10:21 AM
trying to get use to using the span table book, i was confused on how i know what spacings my posts are suppose to span.
so if my floor load width is for example 1800 is that the spacing what my bearers should be? and then in the span table under 1800 FLW then i see what timber i should use to span longways? then find the joist that will span over the 1800 bearers.
am i on the right track?

ausdesign
8th Sep 2011, 03:33 PM
If you provide a sketch it may make it easier.
The bearer span - non-loadbearing - (single or continuous) is determined from the floor load width (FLW) which for an external bearer will be half the joist span. For an internal bearer - which I assume you aren't after - it is the half span load in both directions.

camy18
8th Sep 2011, 03:37 PM
naa no sketch its not for anything in particular, i am just trying to figure out to the australian standards how do i determine post spacings for what size bearers and joists ect, i have the pocket span table book and like it says for the FLW its half span in both directions so does that mean my post spacings are that far apart? internal and external if you get my drift. cheers

ausdesign
8th Sep 2011, 05:02 PM
The bearer span, which is the stump or post spacing, is determined by A - the roof load width in conjunction with the floor load width or by B - for a bearer supporting floor loads only, the bearer spacing i.e. the joist span.
Does that make sense ?

camy18
8th Sep 2011, 05:29 PM
im looking in my span book so for example, my floor load width is 1800, so does that mean that stumps for my bearers are 1800 apart and then i use my table with the RLW to determine the spacings for the posts going the other direction? If deciding to build a new home or large deck what would i do to detearmine my bearer spacings? or can you just choose any FLW you want and just use the appropiate bearers to suit.
so whats the difference between choosing the FLW of 1800 to say 3600, would it just be bigger stump spacings for bearers but obiously a larger timber used for the bearer

barney118
8th Sep 2011, 08:30 PM
confusing, you need to design joist and bearers separately.
Your FLW is a function of your joist span so if your FLW is 1800 then your joist span should be 3600mm. Your bearer span is calculated by your FLW this is the max span between posts/piers/stump. so your 1800 FLW table will have either single span or continuous span between bearers.
You need to select the right table for your bearer span, ie > or< 1m off the ground single span or continuous span.

camy18
8th Sep 2011, 10:33 PM
now i am defenetly confused with what i have got my self into. how about ill start from the start and see how that goes?
for example if i am about to build a house 13000 x 10000, the only load bearing walls being external and its compleatly rectangular.
how would you go about working out proper stump spaces bearers and joists. all in order haa cheers guys
i have only ever worked on a slab and im sure that at some point im going to have to come across this especially for decks as well

barney118
9th Sep 2011, 06:43 PM
Download design IT fro free it solves a lot of issues CHH Australia - DesignIT (http://www.chhwoodproducts.com.au/designit/). I would be using LVL's and wood I beams for joist if building a house. You can change your spans and have an answer straight away. Ie you could use bearers for single storey home hyspan 150x 75mm and span 2m between posts/stumps- 2 on the outside one in the middle@ 5m assuming trussed roof sheet not tile. The beauty of these product you can get long lengths and they are straight as. You must have a slope if not going for a slab.

Bloss
9th Sep 2011, 07:26 PM
Or go to Bricklayer's site and just plug in your numbers.