Thread: Raised subfloor design and finishing options

Groove tube?
kindly explain 🤷🏼♂️

Groove Tube is just steel framing and fittings. Bought from a metal shop rather than a hardware like Bunnings

also known as box span

http://www.metalmart.com.au/wp-conte...-Tube-2016.pdf

Ok, that’s lots of work. Maybe just form up at the front and put some poly waffle blocks in and pour another levelling slab on top?

Originally Posted by riverbuilder

Ok, that’s lots of work. Maybe just form up at the front and put some poly waffle blocks in and pour another levelling slab on top?

OP states it has to be reversible.

Good Morning Mark

Just checking that I am reading your post correctly; Your previous owner poured a concrete floor in the garage that follows the contour of the ground, sloping about 500 mm from highest to lowest corner? You want a firm, level floor; so will the next owner? Should the remodelling be regarded as permanent? A lot of work to remove.

A raised floor would give you good crawl space at the bottom sector but for over half of the floor area the "head height" would be less than 300mm - far too squeezy for me. Add some dusty tubing and the wiring and it becomes claustophobic... You really need access to these as you will inevitably want to change it in the future.

Way back in the 1960-70's the computer industry experimented with raised flooring in a really big way, and eventually decided that it was a dumb idea. Now quite rare. Most commercial buildings have suspended ceilings that conceal water and waste plumbing, electrical and computer wiring, heating/cooling/ventillation ducting, etc.

I have been procrastinating on redoing my shed flooring for some years. It basically comes down to two options - concrete or yellow tongue. The latter is much nicer to walk and work on, and tools bounce safer. I may level existing concrete then sheathe it with yellow tongue!

In your case yellow tongue is probably the better option. Whether you use wood or steel for the framing and joists will come down to $$$$'s and whether you are more comfortable working with wood or steel. Given that you want a vibration free floor and the possible weight of equipment, then you might look at cost and benefits of thicker flooring:

• yellow tongue - 19 mm,
• red tongue - 22 mm, or
• blue tongue - 25 mm.

Yellow tongue should be strong enough, and going thicker is really into belts and braces territory.

Finally, your local council may have rules on this.

Id build a subfloor out of pine, treated if you think it could be damp.
A couple of anchors into the slab.
Leave some floor panels loose, or at least removable, for access.


Ive been involved with building a couple of stages, inside a converted warehouse rather than a garage, but worked well. You don't need to be able to crawl through, just throw cables /push conduit etc.

Thanks to all for taking the time to reply.
Concrete was my first consideration but more digging out the current slab and leveling the ground for a new one but that’s major renovation with underpinning of the house and neighbours yard.
I think the pine sub floor with blue tongue is likely the easiest path.
I will make use of the crawl space only at the highest point for cable and two in floor dust extraction points only. I figure I may as well get trip hazards out of the way once and for all. I have attached two pictures to show what I am on about. The cream is the house level and the bricks are the ground level. Over 10 metres back they meet.
I will also post here as I progress and likely need to work through the unforeseen. Still looking for a good top layer for a little extra finish and protection on top of the particle board flooring.


Mark