How to build low-level decking?

ipeters

I am very much a newbie when it comes to DIY - we only bought our first house in June!.

We have a raised QLD house, all legal height, and underneath the house at the pack is a gravel/soil area.

I am contemplating building a low level deck under the area so that we can walk out there comfortably, and also have an inflatable hot tub & ice bath out there.

Due to the cost, I plan to build it in multiple stages - starting with a 4m by 3m area for the icebath, then following by a 3m x 3m area for the inflatable hot tub, ideally linking the two areas with a small walkway.

I am thinking using the TuffBlocks for the foundation, mainly because they will be on soil, and I plan to add some road base and compact it under each TuffBlock.

I think i would need 2 bearers and 11 joists (including the 2 ends) equally spaced, and I am thinking of using 140 x 45mm timber for the bearers & Joists.

Some questions:

Do i need an additional bearer down the middle, or is a 3m joist span acceptable for a low level deck, given it may have an inflatable hot tub on it?

If i have a bearer down the middle, do i then split the joists into 2 x 1.5m, or do they have to lie on top of the 3 bearers, adding unwanted height?

Does every joist need TuffBlock under them, and so that would mean 3 TuffBlocks per joist... ie: 33 TuffBlocks!??

Do the bearers also need TuffBlocks or do they just sit under the joists?

Trying to keep costs down, and keep it simple, as this is my first decent DIY project.

Any advice welcome before i go too far...

Pictures for context

!underhouse - widthUnderhouse

ipeters

Hi Jacob,

I am just self-critiquing my plans before i start executing.

Regarding the TuffBlocks - i assume that adjustable feet set on concreate pavers would also work, and give my adjustability to get the deck level and add a little height if needed.

Something like this: https://www.bunnings.com.au/100mm-modular-decking-adjustable-support-foot_p8451185

And set on one of these: https://www.bunnings.com.au/brighton-masonry-200-x-200-x-50mm-charcoal-mypave-225-paver_p3451477

I am wondering if these might make it easier to get the decking level as i can make tweaks to each leg as needed, rather than adding/removing compacted group under the tough blocks?

If so, it looks like they just screw into the bearers, but are they needed in the joists as well?

Thanks

Ian

JacobZ

Hi @ipeters,

Again, primarily due to the weight the deck is likely to experience, I would steer clear of adjustable pedestal feet if possible, and if you absolutely had to use them, you'd want to look at ones with a much higher weight rating, such as the Builders Edge 70 - 170mm Bigfoot Xl Pedestal Feet which are rated to support up to 800kg.

Personally, I would be much more comfortable with a deck that sits on the ground with no movable parts beneath it that have the potential to fail, but ultimately it is your deck.

As long as the joists are within the span limits and connected to the bearer with joist hangers, there is no need for them to be supported by pedestal feet.

Let me know if you have any further questions.

Jacob

ipeters

Thanks Jacob.

Appreciate your help/support with all my stupid questions.

In other news, i managed to replace some fence panels on the weekend, including cutting some additional railings with a bevel cut for a gap in the corner i need to add more panels to.

Very simple for most people, but technically my first piece of DIY. Figured it was a good test project before i start on the deck!