How to work out levels on low deck?

[johnc1]

Hi!

I’m thinking of building a wooden deck over this sunken concrete area. But I’m confused with two issues - what ‘level’ to use and if/how I should adjust for the uneven shaped area. See pic below

Level

I’m confused because to make the deck horizontally level/flat, I would build it roughly along the solid yellow line in the picture. But this would mean the deck would get higher and higher compared to the slope of the concrete wall (by about 15cm by the end of the deck). Which I think would look weird. Alternatively see the dotted yellow line if I followed the slope of the concrete wall. Obviously the deck would not be flat if I followed the dotted line. But this may not be a problem as the deck would rarely be walked upon - this sunken area sits near the front door and hardly ever has anyone walking in it. I’m just hoping to clean it up to make it look nicer.  Any thoughts on what to do?!

Size

The distance from the concrete wall to the house on one side (Distance A in the pic) is about 97cm, while distance B is about 93cm. So the area gets smaller by about 4cm. Would I just line up the decking board to the concrete wall at the front, and then cut the last decking board near house to size? Cut this final board like a wedge? 

Any thoughts would be appreciated! 

[MitchellMc]

Welcome to the Bunnings Workshop community @johnc1. It's brilliant to have you join us, and many thanks for your question about building a deck.
 

I'd recommend building the deck flat. Although the deck will have a large gap at one end, it will be neatly covered by fascia boards on the face of the structure. You can use 90mm decking for the top and 140mm for the fascia board. Since it's a decent difference in height from one end to the other, the wider board will assist in covering it.

For the difference in width, 4cm is not an incredible amount. I would work that into constructing the structure and gaps between boards. Build your structure 5mm in from the wall and the concrete slab on the broader end. That's 1cm dealt with, and a 5mm gap is indiscernible. You can then gap your boards slightly wider on the larger end, so if you are using a 5mm spacing, space the boards 7mm on the larger end. Once again not really a noticeable difference. Make minor adjustments to how you build the deck to make up the 4cm. Alternatively, as you've mentioned, you can cut the rear board to suit, which would be a more straightforward approach.

I've put some renderings together for you to illustrate better how you could construct the deck. If you haven't already read through them check out: How to build a deck, How to build a low-level deck and How to build a decking boardwalk.

Please let me know if you have any questions.

Mitchell
 

[Noyade]

Afternoon John!"

"Alternatively see the dotted yellow line if I followed the slope of the concrete wall.

Visually I like the idea of the concrete and deck being at the same level.

Is it decking blasphemy to cut tapered lengths to fit? That's what I was thinking for the piece next to the concrete.

But that's just me - and I've never built a deck. 🤔

Cheers!

[Noyade]

By the way - what's to the right of your photo above John? The same gap between concrete and wall?

[EricL]

Hi @Noyade

Let me tag @johnc1 to make them aware of your question. I think at this point all possibilities are worth considering, it just depends on the final look you're going for. I was thinking along the lines of a terraced step but that would involve more work. 

Eric

[johnc1]

@Noyade Hi, yes it’s roughly the same gap to the right. I’ve only done rough measurements at this stage

[johnc1]

Thanks for your thoughts and picture!

[johnc1]

@MitchellMc Thanks very much for your advice and very professional renderings! I didn’t think about using a fascia to cover the higher end but that’s a good idea. And good recommendation about trying to space the decking boards a bit more to make up the difference in width. That would make it look clean 

[johnc1]

@EricL @Yes I wondered about doing some steps too. Will give it a bit more thought 

[dowd_hardware]

You can always use adjustable deck supports to make the deck flat. Use a pad for suppports - Cruched gravel and a 40mm paver will be enough or you can pour a concrete pad.