Suspended Concrete floor

[HappyHammer]

I've just had plans drawn up for an extension to the house. It's basically a garage with a large balcony above it. I'd like to tile the floor of the balcony and thought I'd need a suspended concrete floor which I believe can be very expensive.

I've heard there are alternatives but my greatest fear is that an alternative will not be stable enough for the tiles.

Any experience with this type of floor or viable alternatives?

HH.

[silentC]

Cement sheet on joists would be OK but you'll need to waterproof it first so it doesn't leak into the garage.

[bitingmidge]

As Silent said!

Don't forget to provide a fall as well, a few inches would be nice. Basically you want sufficient fall so that even if (when) the structure sags a bit, you won't get ponding of any water on the surface, which in turn will minimise your leak potential.

Another no doubt less economical method would be something like CSR Hebel flooring, which will give you an insulated finish, (sound and heat) but will still need the waterproofing etc. (Concrete will need to be waterproofed as well.)

Cheers,
P

[silentC]

Don't forget to provide a fall as well, a few inches would be nice.
You'll have to chock the wheels on the barbie though. :eek:

[bitingmidge]

You'll have to chock the wheels on the barbie though. :eek:
Surprisingly not.

And this is a bit of a misconception, which leads to people putting in flat, puddly floors which leak!

Even at 50 mm across 3m, (1:60) you only end up with 7mm across the width of the barbie. I've seen some level floors that have more fall than that!

Cheers,

P;)

[silentC]

Well, yeah, but that's only two, not a few :p

[Dan_574]

if you want a suspended concrete slab have a look at this site, another great product, http://www.speedfloor.com.au/

[Wildman]

A product that I have used in a previous life as a concretor is bondek from lysaght, http://www.bluescopesteel.com.au/go/product/lysaght-bondek This is as easy as it gets for a suspended slab, prop it up, pour concrete on top and it stays in place after the props come out. I would suggest getting a structural engineer to verify supports, spans, concrete strength and extra reinforcement though. I finished my civil engineering degree 10 years ago but left the industry after 2 years to move to IT so I have forgotten all the details.

Personally, I would forget about poured concrete though due to the weight and I would put in a structural roof on the garage and cover it with 18mm cement sheet. Glue it up to waterproof it, tile straight onto it. http://www.jameshardie.com.au/Products/FlooringAndUnderlays/HardiePanel/TechManual/default.htm
Can do it yourself. Make the roof to domestic flooring standards with regard to beam size and you wont have any issues.

Cheers
Ben

[HappyHammer]

Thanks guys,

Large sections of the tiled floor will be exposed to the elements and as I'm a lot closer to the ocean now some of it will contain salt. It also mentions bath or shower use but not external use. Is there a particular type of grout that would be best for the tiles. The James Hardie site says it should be at least 3mm and no cement mortar which seems to be to allow for movement.

I had a look at the Hebel soundfloor which doesn't mention external use and at 75mm thick sounds expensive.

I'm leaning towards the cement panels on joists if it will survive the weather.

HH.

[silentC]

Our house is 100m from the beach. We've got a balcony out the front which is made from cement sheet on joists. The joists have been replaced because they were hardwood and the joins in the sheet weren't sealed so they rotted. It isn't tiled - had pebble coat on it years ago but I scraped that off when I was 19. The cement sheet has to be at least 35 years old because that's how long we have been in the house. It will out last you. Just make sure you seal it well and don't let any moisture through onto the timbers underneath.

For the grout, I've only ever used off white cement and Sydney sand outdoors but if Hardies say it's no good, I'd probably go to a tile shop and see what they have in the way of flexible external grouts. There might be one with an additive that is suitable for external use.