Low-level deck - ledger bolt size length type?

Hello all

I'm about to commence a low level deck at my home. It's a concrete base with a ~180mm height clearance.

Was just about to commence, but I seem to be over thinking alot of aspects.

The deck will be 3.7m X 4.7m. I was initially having a ledger on both the sliding door side and wall side. Either bolted using ankascrews, dynabolts or even plugs with screws? I'm not sure what size but thought m8 X 90mm would be suffice? Thoughts? Alternatively I can not connect the ledgers directly to the house and just use L brackets bolted to the ground?

After the ledgers are installed I'll be using 90x45 joist to run inline with the ledger. I'll probably grab a few joist hanger brackets to connect the joist and ledger together for extra strength.

Secondly the sliding door seems to drop slightly at the opening. When I marked out the deck (using a laser level), it seems to drop 12mm over ~3m. As I want to build the deck inline with the sliding door if I make it perfectly flat it will be obvious as it's a monument rail frame that would be visible on one side and slowly disappear to nothing. Intention to have 2-3 mm of the rail sticking up above the finished floor height of the merbau. Can probably be seen and understood easier in the images.

Any advice and ideas are greatly appreciated.

PXL_20230312_114337455.MP.jpg

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Comments

KatieC

Hi @leesk,

First, let me send you a warm welcome to the Bunnings Workshop community! It is awesome you have joined us and jumped in with a great decking and sliding door question. Our resident DIY expert @EricL will be back online later this afternoon, so let me tag our great Workshop members @Adam_W, @Jewelleryrescue, @MGusto, and @LePallet to see if they have some advice to share. In the meantime, check out this Top Ideas article Top 10 most popular deck projects for some added inspiration.

We would love to see your deck come to life, please update us with progress photos.

Katie

Jason

Hi @leesk,

You might also find Adam's guide How to build a low-level deck useful while you wait for responses to your questions.

Welcome to the community. We're looking forward to seeing your new deck come to life.

Jason

EricL

Hello @leesk

Thank you for sharing your question about your low-level deck. Although you can attach a ledger to your brick wall, it's not always necessary. Because you are building a low-level deck, it is possible to build it as a free-floating frame independent of the brick wall. Using angle brackets is an excellent method of holding and anchoring your decking frame to the concrete.

If you look closely at the brick pattern under your sliding door, you'll notice that the bricks actually angle down to compensate for the concrete base slope. This tells me that your sliding door is level, and your concrete base is not, one other way to check this is to put a traditional spirit level on the bottom slide of your door frame.

The good news is that you can adjust your deck frame to level with your door frame, as I mentioned earlier, I suspect that the concrete base is offset. I suggest having a look at this featured project - Low-level composite deck over concrete and soil by @oninpena. This is a very good example of an independent decking frame that is held in place with angle brackets and pedestal feet. I also recommend looking at this guide - How to build a deck by @MitchellMc.

Here is a link for ideas and inspiration: Inspiring low-level deck builds

I also suggest having a look at the Bunnings guide to building a deck:

If you have any other questions we can help with, please let us know.

Eric

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