First Big Project Low Level Freestanding Deck

[ZacEvans911]

Hi Team, 

First time on here so please go easy ! I am attempting our first deck project at the house. Previously before there were 40x40mm pavers with the compacted gravel base underneath. The pavers have been removed and we are looking to add some deck. 

So the area in question is approx, 3.9x6.2m give or take to suit an even board coverage. The house is an L shape, 150mm below from the weephole is the area we have to work with. There is a slight gradient from the house of around 10mm difference from start to finish. Area is undercover and water shouldn't pond. There is a drain 80mm high, the 90mm joist can be laid either side of them giving height to be able to lay the boards. Probably wouldnt be able to picture frame the deck due to framing method. 

I was thinking of doing the following: 

1- Lay black builders film over the area

2- create the frame consisting of 15 90x45mm h3 joists at 437mm from centre. The joists would sit on black wind up pedestals starting at 25mm heights. at around 500mm apart on each joist. ( 6 pedestals per joist ) 

3- Lay the merbau boards, shortest piece closest to the house. and work outwards. around 38 boards needed at 3.8mm gap according to blocklayer.com

4 - cut and add an end trim peice on the outer sides of the deck. 

Has anybody worked with the pedestals before? Will the decking look on without any frame/fascia on the sides adjacent to the house? Will the decking look asthetically pleasing tucked just under the brick lip against the house 

Any help would be great  

 rough idea of how the price against the house may look likearearough sketch of measurementsweephole and close up of baseweephole height

[bruce93]

Hi @ZacEvans911 

I haven't used the pedestal type before but I have worked with a product called Klevaklip adjustable joist support. This product is designed for a concrete base and it worked very well. 

Also in regards to using merbau. I would be using a 5mm gap between boards as a minimum opposed to 3.8mm. Also make sure you stagger your joins so there not all at the same point in the deck.

Cheers,
Bruce

[pepsp]

Hi @ZacEvans911 I have used the Bigfoot builders edge pedestal foot over a concrete area quite similar to yours. Worked a treat. The deck has been in for 2 months and no movement to report. So far so good!

 I built my deck at floor height of the house, had about 250mm to play with. It joined in with the weather board at the side of the house really well. I think adding the deck on has improved the look of the back area significantly.

[ZacEvans911]

Thanks for that! I’m hoping the freestanding wil have the same effect 

[ZacEvans911]

Hi Bruce, thanks a lot. Spacing size noted! In terms of staggering my joints as the lengths will come random from 1.8 + any particular pattern or just randomly stagger and play around with it as Wasting boards is a fear due to $$

[MitchellMc]

Welcome to the Bunnings Workshop community @ZacEvans911. It's fabulous to have you join us and many thanks for your questions.

It's great to see you've already received some helpful replies from our experienced members in this area. 

I would advise against using a solid builder's plastic under the deck. Instead, I would suggest using weed matting. If any rain gets under the deck, the weed matting will allow it to drain away. You should find this article useful: How to build a low-level deck by @Adam_W.

Regarding the staggered lengths, it's just a matter of jigsawing them into place, and it's less of an issue when you have many different lengths of timber to play with. Just make sure no two parallel boards have their joins next to each other.

I'd also agree that a 5mm gap would be more suitable than a 3.8mm. When timber is damp it swells, so a 3.8mm gap on dry boards could turn into a 2mm gap on wet boards. Next thing you know boards are getting pushed off because they are too close. A larger gap also makes it easier to sweep debris off the deck and allows it to fall through instead of getting stuck in a smaller gap.

We look forward to hearing more about your project and following along with the build. Please let us know if you need further assistance or have questions.

Mitchell

[bruce93]

Hi @ZacEvans911 

In regards to fear of wastage. No one likes wastage but when building a deck the rule of thumb is to allow an extra 5% of materials for this exact reason.

My tip to make sure you reduce your wastage would be to lay out the boards as best you can before starting to screw down. Rather than screwing one row down then working out the next row.

That's how I would do it.