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How to attach joists to end rims for deck extension?

tejmankar
Junior Contributor

How to attach joists to end rims for deck extension?

Hi,

I am extending my deck and planning to build a long bench on top of it. The bench will weigh roughly 500kg by the time I build the frame using 90 x 45 h3 and then completing it using composite decking boards on the face. The bench will be 4.4m long. I would appreciate some guidance on the flooring frame please. The frame is roughly 6.4m x 1.2. I have supported the rims using stirrups every 1.2m. I have joined the joists to the rim by using two bugle screws (100mm) on each end. The joists are roughly 450mm apart. Is it sufficient to have joists joined using the bugle or is it better to also add joists hangers please to give the structure the strength to support 500+ kgs. The boards on the frame are temporary to walk easily. Many thanks

 

 

 

.20211223_092428.jpgExisting deck extensionExisting deck extension

EricL
Bunnings Team Member
Bunnings Team Member

Re: How to attach joists to end rims for deck extension?

Hello @tejmankar

 

Thank you for sharing your decking project with us. I'm afraid that using joist hangers will not be enough to support the weight of your table. On the condition that the table will be staying in one place, the area where the legs will be positioned must be reinforced to carry the weight of the table and the items that will be put on top of it. 

 

I recommend reading this discussion - Low-level deck that needs to support tons of weight by @Adog. To summarize the recommendations made in the discussion. It's suggested that you double up the joists where the table will be sitting and space them so the legs can sit on the joists rather than the decking boards. It's also recommended to use pedestal feet directly under the legs. This is so that the weight of the table is on the ground and not on the decking frame.

 

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

 

If you need further assistance, please let us know. 

 

Eric

 

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tejmankar
Junior Contributor

Re: How to attach joists to end rims for deck extension?

Thanks for the prompt reply @EricL ,

Essentially, I will be building a seat like this. Please have a look at the photos attached.

The load will be spread across the frame. I have included another photo with the boards removed where the frame of the seat will seat. I will but covering the seat the floor with boards after the fact. FYI, under the weed mat, there is soil. Looking forward to your suggestions

 

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20211223_160314.jpg

EricL
Bunnings Team Member
Bunnings Team Member

Re: How to attach joists to end rims for deck extension?

Hello @tejmankar

 

Thank you so much for posting the proposed structure you're putting on your deck. The question that comes to mind is, how much space do you have under your deck? I would still go with the original suggestion made earlier, but this time you'll need to find out if you can put a paver and pedestal feet underneath. As the weight is now spread out, I propose putting supports along the length of the footing of the structure. As I mentioned, it would be best if the weight is placed on the ground rather than the frame of the deck.

 

I suggest putting a Pedestal Foot every meter both at the front and back of the joist where the footing of the structure will be placed. I recommend using Brighton Masonry 300 x 300 x 40mm Charcoal Mypave Paver or similar to serve as a base for the pedestal.

 

If you need further assistance, please let us know.

 

Eric

 

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tejmankar
Junior Contributor

Re: How to attach joists to end rims for deck extension?

Hi @EricL 

 

Thanks for the response. Your suggestions make sense. There is soil under the weed mat so I can dig a little and even pour a little concrete (100mm) and then place the foot on top of it. I have attached another photo with markings on it. The red rectangle is where the bench will be placed roughly. The purple circles is where the stirrups are. If I understand correctly, you are recommending to insert the pedestal foot where I have got the green markings under the joist. Is this correct please? Also, would it be required to have double joists and double noggins if we put the inserts in? Another question is will the joist hangers give the joists additional strength. They are currently held by bugle screws (100mm) Thank you.

Inked20211223_160314.jpg

EricL
Bunnings Team Member
Bunnings Team Member

Re: How to attach joists to end rims for deck extension?

Hello @tejmankar

 

You've got the idea, my friend. However, I still recommend using the paver as waiting for the concrete to dry will take at least another week to hit full strength. But I leave the decision to you. Using bugle screws is fine adding the joist hangers adds extra strength. Adding extra joists will make your frame that much stronger. I tend to over-engineer things so I agree with your ideas. You can imagine the weight of the seat you are about to build plus the number of people who will be sitting there. It has to be strong to take all that weight.

 

If you need further assistance, please let us know.

 

Eric

  

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tejmankar
Junior Contributor

Re: How to attach joists to end rims for deck extension?

Hi @EricL 

 

Sorry, one more question please. Would you recommend putting some blue metal on the soil and then paver on top or the paver can go directly on the soil please?

 

Thanks,
Tej

EricL
Bunnings Team Member
Bunnings Team Member

Re: How to attach joists to end rims for deck extension?

Hi @tejmankar

 

Placing blue metal should be perfect. Make sure to tamp them into place so that the paver will not sink or settle. If you have any other questions about your project, please don't hesitate to post them. Our members are more than happy to provide you with advice and information.

 

If you need further assistance, please let us know.

 

Eric

 

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tejmankar
Junior Contributor

Re: How to attach joists to end rims for deck extension?

Hi @EricL ,

 

I have had a stab at it. Please find some pictures attached. Does this look ok ? I might throw some concrete around the edges to hold it steady. 

20211224_100518.jpg

 

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EricL
Bunnings Team Member
Bunnings Team Member

Re: How to attach joists to end rims for deck extension?

Hi @tejmankar

 

Very nicely done, but I suggest adding more blue steel to give yourself a good base for the paver. I recommend not removing the weed mat and placing the blue steel over the weed mat.

 

If you need further assistance, please let us know.

 

Eric

 

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