# Forum Home Renovation Flooring  Timber Floor on top of uneven concrete slab

## lateral

Hi Guys 
I have a workshop slab (6m x 9m). The problem is that it is not level in the centre. It "dishes" and is uneven. 
I would like to install a timber floor to make the floor level. What is the best method to lay a floor directly on top of a slab? 
Can I forget bearers and just lay the joists (6m) directly on top of the slab and the stick pieces of fibro under the 6m lengths to get the correct level and then simply lay some sort of sheet flooring? 
Any help and ideas would be great! 
Regards
Greg

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## glock40sw

G'day.
Use a self leveling compound. You pour it on and it runs to the low points and fills them. It's used all the time by flooring installers.

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## gordonwindeyer

What are the names of some of the self leveling compounds? And do you know what it costs per sq m for the materials?

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## lateral

Thanks for the information. 
I was thinking of using self leveling stuff but I thought that they would only fill upto 5mm. I have troughs of more than 25mm. 
I will ring a few suppliers and see what they suggest. 
Thanks
Regards
Greg

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## Pulse

The self levelling compounds can be used in layers to build up. They can be expanded with sand too if you have deep sections to fill. Bunnings stocks Lanko , another brand is ardex. 
Cheers
Pulse

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## lateral

Hi Guys 
Looks like I am going to lay a timber floor on top of the uneven slab as I like the idea of walking on timber and not cold concrete. It will also mean that I will be able to simply screw or nail directly into the floor when I am building my new benches etc. 
I have a few questions: 
The area is about 6m x 10m and I am planning to lay the joists to span the 6m and Dynabolt them to the slab with suitable packing to bring things level.  
1. I am thinking of using 70mm x 45mm framing pine...any problems? 
2. I am thinking of using 2400mm x 1200mm x 21mm T & G Plywood Flooring (Mr Plywood). This will enable me to use 600mm centres......any problem? 
Thanks for any help you guys can provide. 
Regards
Greg

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## DJ's Timber

I would go with 450 centres, my last shed had 22mm chipboard flooring at 450 centres and with the weight off the machinary you sometimes notice a bit of flex in the floor

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## lateral

Yeah, I was thinking that myself. 
I assume you had  T & G Particle board flooring? Did you have any problems with it?

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## DJ's Timber

> I assume you had T & G Particle board flooring? Did you have any problems with it?

  Yep that's the stuff I used, didn't have any dramas with it, apart from where my lathe was, but that was mainly in the bearers and joists

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## glock40sw

Don't forget to glue the yellow tongue to the bearers. 
450mm centres would be better and allow more weight to be bourne by the floor.

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## joe greiner

Particle board for flooring? Bah! Shouldn't be allowed to sell it as such. OSB maybe OK, but plywood best. 
Joe

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## lateral

Thanks guys 
Perhaps I will use T & G Particle Board and paint it...

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## lateral

Hi Guys, 
Just to update you all... 
I have investigated using a Self leveling Compound and it is far too expensive to do it properly. i was quoted about $4k - $5k. 
Whilst I am capable to make up the floor joists I have decided that I will get a Roof & Truss company to make up a number of "pre-fab" floor modules as per my specs. This will enable me to simply lay them down, level them up then bolt them down in the quickest possible time. All I need to do then is lay the 21mm plywood T & G flooring (I have decided against particle board).  glock40sw suggested gluing Yellow Tongue and I assume that I should also glue the plywood? What is the best glue to use? Also, what are the best screws to use to attached the plywood to the 70 x 45mm joists? What problems will I encounter if I don't glue? 
Also, I am thinking of painting the floor white so that it will be a bit more resistant to moisture, look better and reflect more light....does anyone see any problems with this? 
Thanks
Greg

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## Larry McCully

ok ok ok here's the go for you bro. You will be better of at 300mnm spaces for your battens. That is a safe span for high load applications. This spacing is used commonly on spacings to stages in auditiorums. If you are going to put machinery on your floor and high load points, then 300 is your answer. 70x 30 hwd battens . Pin your first line down 70mm of the wall and then mark out in multibiles 0f 300. Follow the diagram attached. I hope you will be able to follow the steps.

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## Larry McCully

Ther should be a attachment i attached

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## lateral

Hi Larry 
Thanks for the info but there was no attachment. 
Currently the only machinery I have is a bandsaw, Triton workbench and router table and some moveable benched on wheels so I donlt think the loads will be too much.

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## Larry McCully

Hey bro, I am trying to attach the file, but it is 700kb long, and the attachment bit will only take 100 kb. Do you know any other way to attach  it.

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## Larry McCully

> Hi Larry 
> Thanks for the info but there was no attachment. 
> Currently the only machinery I have is a bandsaw, Triton workbench and router table and some moveable benched on wheels so I donlt think the loads will be too much.

   Then 400 to 450 centers will be fine.

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## lateral

Hi Larry 
So that I could get the ball rolling as fast a possible, I decided to get a framing company to make up a number of floor frames in modular form so that all I had to do was to lay them down, bolt them together and level everything correctly. 
Well, I laid them down and have levelled around the outside of all of the "modules" starting from the highest spot of the slab and dyna bolted them to the slab. I used a digital level (these are great!). I have used fibro for the majority of the packing and also used some plastic "wedgies". 
I am pretty sure that I have the levels around the outside correct and now I want to know what is the best way (and hopefully a fast way) to get the levels correct in the centre. Just to remind you, the slab is 6m x 10m and I will be laying 21mm T & G Plywood flooring and I have the joists running along the 6m. I also had the framing company put in noggings. Do I use a string line or some other method? 
Thanks a lot for 
any help you can provide 
Regards
Greg

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