How to build a ground level deck?

KTreth

We want to build a deck under a patio at ground level. Because of the limited space the deck level needs to be the same as the existing pavers to prevent chairs from toppling backwards! There are too many pavers around the house and to the pool to change their level. The decking area will be about 5.6 x 4.6. We can't bring the decking out further to accommodate the chairs as it will create an access issue.

If we use h4 bearers what clearance do we need from the ground (sand pad). We'll be digging pretty close to the house wall and footings. We're concerned about making this unstable for the house.

JacobZ

Hi @KTreth,

A warm welcome to the Bunnings Workshop community, it is fabulous to have you with us.

If you are planning to use H4 timbers, such as this 140 x 45mm MGP10 H4 Framing, then they are treated for direct contact with the ground and you can reasonably sit them directly on the sand pad beneath, however, I would aim to have at least a 20mm gap so that they are not sitting in any pooling water that accumulates.

Assuming you use a single-tiered frame where the bearers and joists are on the same level, you will need to account for a small gap of around 20mm beneath, the thickness of the frame, 140mm as an example, and then the thickness of the decking boards which let's say are 22mm thick. This would mean you need 184mm of space below the height of the finished deck. If you were using pedestals to support your deck, this would increase slightly. If you concreted in posts, which I prefer as a method of construction, this measurement would remain the same.

Considering a brick paver is usually around 50mm thick, then you would only need to excavate an additional 130mm, which is unlikely to affect the footings of your home. If you were particularly concerned after you'd started the excavation, I would consider contacting an engineer for their thoughts.

With only your description to go off, I can't see any issues with your plan, however, you should contact your local council to check if there are any requirements on their end for the construction to proceed.

You might like to check out a few of the following articles for some further guidance as the project progresses.

Let me know if you have any further questions.

Jacob

KTreth

Thanks Jacob. That's the advice we were hoping to get. Being covered, only the very outside edges get wet.

JacobZ

Hi @KTreth,

I can't imagine it would get much water, but there is always some potential when you have driving rain.

Regardless, H4 timber is going to be your best option, and I'm sure you will have a fantastic deck that will stand up to the weather.

Please keep us in the loop, it would be great to see how your deck build goes.

Jacob

MitchellMc

Hi @KTreth,

I thought I'd just mention another option which would be to leave your pavers in position and instead lay Dekart modular decking tiles over the area. You'll get a similar effect to a deck, only slightly higher than your current pavers without the need to excavate.

Mitchell