Share
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
.
Hi @EricL ,
I have mixed cement with blue metal. I have then covered with weed mat and placed paver on top over some more blue metal. It feels sturdy now 
thanks for the guidance. Please find some pictures attached.
That looks excellent, @tejmankar. Your added effort will ensure the longevity of the project.
Be sure to update us with some images when you're finished.
Mitchell
Hi @tejmankar,
What's the context surrounding your question? Is the deck bearing weight as was needed here? Whether you laminate two joists together or add one in between, it would add a similar amount of strength and any difference might be inconsequential. You're adding the same amount of timber to the structure either way.
The structure will bear a similar amount of weight either way, but the decking boards get supported better with and additional joists in between as they don't have to span as far. A 450mm spacing is more than adequate for a standard deck, though.
Happy New Year to you too!
Mitchell
Hi @MitchellMc ,
The work I have just done is to extend the existing deck. Please find attached the photos of the existing deck. The existing deck will also hold a bench in C shape and will be 3.2m long and 1.5m on the sides. Please find attached the design of the upgrade. My concern was to make sure that the deck can hold ~1000 kgs. as the bench it itself will weigh about 550kgs to 600kgs and the people sitting will add to it.. I wanted to make sure that the deck frame is very strong. Any thoughts? I have changed the design to move the bench on existing deck rather than what I just built (extension). The extension will now have the table in the new design and bench will move onto the existing deck. Looking forward to your comments.
That extra weight is being evenly distributed over the entire area @tejmankar. You don't need to worry about the weight of people. That's factored into standard deck construction. A deck can hold people and additional weight above what would be considered ordinary usage.
If you wanted to make the area really strong, you could add another two posts at the red stars for support and then run additional joists across, as previously mentioned. I don't see any point running additional joists unless you add the additional supports to the mid-bearer. That's the weak point.
Mitchell
Thanks @MitchellMc
I will also be adding blocks (noggins) every 450/500mm which currently do not exist. Do you see any point in adding joist hangers to the existing joists please? I will consider adding two additional posts before I decide to add joists.
Also, in terms of additional joists - The current width is 2700 with the bearer at the centre so the span is roughly 1350. Would it be ok if I add joist from one end (using joist hander) and rest it on the centre bearer do the same from the other end and then join them together in the centre using a piece of timber. Essentially they will be 1350mm (90x45) resting on the centre bearer and joined in the centre using an overlapping piece of timber. Reason for asking is I can't find 2700mm timber easily but I do have 2m lengths which I can use. Thoughts?
Hi @tejmankar,
As long as the existing joists are sufficiently connected, I see no reason for adding additional joist hangers.
You could graft the two 1350mm joists together in the middle. However, they'll be far stronger in a single length. With your proposed method, the central bearer will be carrying the majority of the weight, whereas if the joists are of a singular length, they'll be bearing some of the weight.
Mitchell
