Bearer & Joist dimensions for Sub-Floor

[attie]

Thanks. Just a little confused!

I am working on 450mm spans for my joists and about 1500mm spans for my bearers. Just want to know the space between stumps.

If I said 1500mm between stumps, would that be safe?

Greetings guys
This is my first post here so I had better introduce myself. My name is Wayne, I'm a retired builder who worked in the Whitsundays and now cook fish and chips here in Mackay, Queensland. Not realy old enough to retire and intend to build a house and some units for myself shortly but because I've been out of the game for 10 years I'll surely have some questions for you.

Golfer, the old rule of thumb when using F14 plus hardwood bearers and joists was - "1/2 the span plus one"
eg. Joists, 1500 span [5 ft.] 1/2 = 2 1/2" so say 3" plus 1 = 4" x 2" [100 x 50]
Bearers, 1500 span [post to post] as above x 3" [75] = 100 x 75

[vGolfer]

Thanks very much for the info everyone. Much appreciated.

I have had about 3 blokes come over to give quotes on the sub-floor - ie rebuild the bearers and joists with stumps underneath. Just to set the scene, it's an old single fronted solid brick Victorian home in Melbourne. The joists sit on bearers in the middle of the rooms and wall plates along the edge of each room.

We need our levels brought up about 20mm throughout the house. One guy suggested doing bearers parrallel and close to the walls as well as in the centre of the rooms. He also wanted to put bearers right down the hallway which is about 12m long but only 1.35m wide. This seemed like overkill to me. It's going to be a lot more expensive as we'll need more wodd and a heap more stumps.

What do you guys think?

[vGolfer]

Just following up on this thread...

Just wondering what the standard is for flooring? We're getting floorboards laid down a hallway and an open plan area but carpet in the bedrooms.

The people laying the floorboards are saying that the cleats they use to nail in the florboards grab much better into ply than they do into the yellowtongue. I guess that sounds right but just wanted to get some advice as to what may be the pros and cons between yellowtongue and ply.

Thanks

[Skew ChiDAMN!!]

One thing I've noticed, most of the replies here deal with the bearer spans. 1800mm between stumps along the bearer is acceptable, provided the bearers are of acceptable quality. ie. low-end F17 or top-end F14. (Just 'cos a piece of wood has a rating doesn't mean it didn't just barely meet the required specs... waht's deemed acceptable seems to be lower'n'lower quality with every passing year.)

But, IMHO, the joist span ie. the spacing between each bearer should be less, more like 1200mm. So the stumps would be set in a 1800x1200mm grid. Next thing you know, people'll be saying the joists should be spaced at 1800mm. Sheesh!

[Auspiciousdna]

You say you’ll be carpeting the BR”s, why not take that coin and buy nice floor boards for the whole house.

P.S. I,ve never heard of anyone having any trouble with a house built to Australia standards. Why go better?

[attie]

"But, IMHO, the joist span ie. the spacing between each bearer should be less, more like 1200mm. So the stumps would be set in a 1800x1200mm grid. Next thing you know, people'll be saying the joists should be spaced at 1800mm. Sheesh!"

With respect, you should have been taught at tech. how to calculate spans and load bearings. A high set home is a typical example of pratical use of materials. If your bearers were to be 1200 apart a 75 x 50 joist would be sufficient