How to build a low-level deck over grass and materials?

Hi there team Bunnings,

Hope you are well,

I was wondering if you can kindly help me with the following as I'm planning to build a low level deck due to land sloping down towards my backdoor.

1. My pergola is 25sqm, would I need to connect the downpipe to a storm water drainage? the downpipe is on the last pole on the right hand corner. The storm water connection is very far down the house on the side.

2. What is the minimum clearance would I need for a low level deck if i'm planning to use Galvanised post, H4 for bearers and H3 for joist?

3. As my land slopes down towards my back door and water seems to flow towards the house, is there a drainage issue I need to think about? If so, can you please kindly recommend me a solution?

4. I plan on digging up the grass, which weed mat would you recommend to purchase? Would you also recommend the clips or drainage sand?

Any additional advice to what I have not thought of would be much appreciated 🙂

Many thanks for your help!!

20221110_182646 (1).jpg

Find more posts tagged with

Tools and Materials

Decking and Paving

Building and Construction

Landscaping

Comments

MitchellMc

Hi @penpan8988,

Have you considered a slightly raised deck that you'll walk directly out the door and onto instead of down the stairs? You can add steps down from it and into the garden off the deck. The reason for asking is you'd typically create a low-level deck when the door threshold is low to the ground, unlike yours. Secondarily if you have a sloping yard, you'll need to deal with the water runoff and the downpipe, as you can't have that water sitting under a low-level deck. By having an elevated deck, you could possibly avoid installing additional drainage and ease of access would be improved since you don't have to walk down steps onto the deck.

To answer your questions, you'd need to connect the downpipe and Slotted Draincoil you've run across the rear of the house to collect runoff to the stormwater. I can't give you an exact minimum clearance for your deck, as the higher you can make it, the better. Limited airflow through the deck's structure is the leading cause of the early onset of decay. Your H3-treated joists are rated for above-ground use, but once again, the closer to the ground you place them, the less airflow there will be. Any standard weed matting will be fine, and I'd recommend weighing it down with drainage gravel.

Check out this step-by-step guide on How to build a deck.

I've put a rendering together for you below that shows a possible construction method.

Please let me know if you have further questions.

Mitchell

penpan8988

https://www.workshop.bunnings.com.au/discussion/comment/23652#Comment_23652

Many thanks for your reply Mitchell. I really appreciate it 🙂

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/74610#Comment_74610

No problems at all, @penpan8988!

I'm super keen to assist you with this project, so make sure to keep us updated and reach out if you have any questions or get stuck.

Mitchell

penpan8988

https://www.workshop.bunnings.com.au/discussion/comment/100910#Comment_100910

Hi @MitchellMc

Hope this message finds you well.

I was wondering if you can shred some light on my decking planks . So my deck was built exactly like your drawing above.

My builder used Merbau purchased from Bunnings as attached. The deck was oiled using Cutek. Can you please kindly confirm if the lines on the deck are normal? Or are the planks faulty and need replacement as the rest of the decking planks are much more uniform and look perfect.

Many thanks!

EricL

https://www.workshop.bunnings.com.au/discussion/comment/117578#Comment_117578

Hello @penpan8988

Thanks for sharing your question about your newly constructed deck. It looks like the manufacturing saw cutting the panel has left an impression on the timber surface. You can try two solutions, the first is to use an orbital sander and sand off the pattern on top of the panel until it's gone. Once you've determined that the damage has been sanded off you can repaint the panel. However, should the pattern still be there then it's likely that it travels all the way through that panel.

The second choice is to return these two panels to the store and request for an exchange. I propose speaking to the timber yard team member and requesting that these two boards be replaced. It sounds like a fantastic project. If you need a hand with the return, please let me know.

Please keep us updated, we look forward to seeing your deck complete.

Eric

penpan8988

https://www.workshop.bunnings.com.au/discussion/comment/127034#Comment_127034

Thanks for the reply @EricL

May I ask, say if these planks don't get replace, will it compromise the longevity of the deck?

Also can you please confirm this is normal? Not sure what this is...

I was just looking beneath my deck and saw this. The deck was built using H4 and H3 bearers and Joist.

Many thanks for your help 😃

EricL

https://www.workshop.bunnings.com.au/discussion/comment/133300#Comment_133300

Hello @penpan8988

It looks to me like a bit of concrete got splashed onto the decking frame. I suggest using a hammer to break up the surface of the concrete and scrape away the rest using a Craftright 5-in-1 Scraper.

If you need further assistance please let us know.

Eric

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/117578#Comment_117578

Hi @penpan8988,

To my eye, what you've pointed out there looks to be a perfectly normal trait of Merbau timber. It's the figure of the wood caused by the grain structure and is a unique characteristic of natural timbers. I have a few similar sections on my Merbau deck. Now, if this is the only section on your whole deck, then I can see why you might be concerned. However, there's no need to be. It's not defective and definitely does not need to be replaced.

Occasionally, you'll see a board that wasn't milled correctly and has a rough patch on it. But I don't think that's the case here. Certainly not for the majority of what you've pointed out, but possibly on the area I've indicated in the image below. If this area is rough, it would suggest that it wasn't finished correctly. Normally you'd just lay the board with that side facing down, so flipping it over might be easier than returning it.

If you were to show me the last image, I'd congratulate you on your beautiful Merbau deck, as there are no issues I can see. Do you have some pictures of the whole deck? I'm sure it looks amazing!

Well done.

Mitchell

penpan8988

https://www.workshop.bunnings.com.au/discussion/comment/127043#Comment_127043

Thanks for your reply @MitchellMc

Yup the area is rough. I was wondering - even with a rough area will this compromise the longevity of the wooden plank?

Of course. Photo per below. All the materials were purchased from Bunnings:)

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/133337#Comment_133337

Your deck looks amazing, @penpan8988!

In my opinion, I don't believe that the rough area will compromise the longevity of the plank. I've included an image of a similar area from my deck (it's due for a re-oil). I have a few areas like this on the deck. It was built over a year ago, and I can't see any signs of degradation. Prior to your next oiling, you might like to give the area a light sand with 240-grit sandpaper to smooth it out. Just make sure to sand along the board and not across it. Sanding across it might introduce scratch marks.

If you are concerned about the board, I'd be more than happy to facilitate an exchange of it for you.

Mitchell

Child Item