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Hi,
I am planning some decking and a pergola, I would like to know if I am required any planning or building permits for the following:
1: extend my decking area from my alfresco (which is situated on a slab) and extending outwards in 3 directions, adding approx. 18sqm to the current decking area, the new decking will require footings of course, and be attached to the existing bearers on the alfresco. so I was wondering how deep footings should be ideally, post holes will be 1117mm on centre along the length, and 900mm on centre on either side.
decking will be 7200mm long and 4500mm wide, with a 380mm wrap around on one side.
currently the decking perimeter is the two brick piers, see below for my plans.
2: also planning an open "Hampton style" pergola that will cover the 18sqm decking, which will be attaching to the alfresco (approx. 2300mm above planned decking) so much stronger footings required (see the above pictures, the 4 deeper footings which are offset from the deck footings will be supporting the pergola, I'm not sure on minimum required depth but I will probably attach the posts to stirrups which will be secured in the footings.
3:A second smaller decking approx. 2.8 sqm in size from the laundry exit which will be anchored from the brick wall and require some footings, however i'm unsure as to the minimum depth for footings.
I called Casey council who recommended talking to a surveyor, but am I better to talk to a builder? and I am unsure about having plans made up professionally, at least for the decking and pergola and I haven't worked out how much materials will cost yet but if I am able to build everything myself I would like to save on costs where I can.
thanks heaps
using the same design as the other project and as I have time to prepare for the next stage I would like to know if the overall integrity of this larger decking looks good.
This deck will be a freestanding deck adjascent to the Alfresco, essentially extending the area but not attached to the house. similarly it will be a single layer construction to keep low profile.
-Deck size will be aproximately 7.5m2
-Post spacing (horizontal to drawing) are 1483mm O/C and front to back 1269mm O/C
-Bearers (140 x 45) 4561mm lengths (horizontal to drawing) and 1554mm front to back on each end.
-Joists 450mm O/C
also a side note: overhang from centre of post to outside edge of decking is 225mm, more or less just to facilitate the 140mm merbau picture frame style boarder. and finally the posts will be notched out to support the bearers as advised in the other design.
thanks!
Hi @TimGeo,
I'm not a great fan of those 90 x 45mm joists spanning 1200mm; I typically recommend 1000mm max. I'd recommend adding another bearer down the middle and additional posts. 1200mm, I believe, is within the span limits of 90 x 45mm, but you can end up with a spongey deck that bounces underfoot. It's the difference between a rock-solid deck that's built above spec and one that just meets the minimum requirements. I know installing more posts is additional work, but I feel it's well worth it. Alternatively, go with the extra cost and use 140 x 45mm for the joists as they'll span the distance easily.
Please let me know if you have any questions.
Mitchell
added another bearer and some posts as you mentioned bringing the joists down to 555mm span, definately think even with the 140x45 joists I would still feel some movement, maybe not, but I would feel better with more posts, and with an auger it will take no time to dig
Finally able to provide an update and some final pics of the end result!
I had no trouble digging 5 of the six holes but due to the location of the deck, the concrete holding up the garden wall post was in the way, and there was a French drain style pvc pipe very much in the middle of the pathway filled with scoria, absolute pain to dig out, very lucky I was able to fit the last post snug in between!
I positioned the deck with additional supports and secured the posts to the deck frame so they were floating in the holes and filled them up with cement.
Here are a couple of in progress shots
Here you can see I had to move the post location however it doesn't compromise the structure
one thing to note that although I used high quality fixings for the merbau that are self drilling, straight shank, I noticed that if I pre-drilled and countersunk the holes slightly there was next to no fibre tearout around the screws for an even tidier look!
And finally the finished product. The decking part was fun, trying to get them dead straight was a slow task but very rewarding! And the final product looks even better than the design!
Thanks everyone for your input and guiding me on the way to my best ever DIY project to date! there will be much more to come
What a little ripper @TimGeo! That looks fabulous! I'm so pleased to see that you've achieved exceptional results due to your excellent planning.
I can't wait until you get started on the big deck now.
Many thanks for sharing your results with us.
Mitchell
I have made changes to my other decking designs and decided to go for the 140x45 for majority of the frame and I think it's the better choice, saving a small amount of money on raw materials for a potentially less sturdy construction doesn't do my ocd any favours haha!
I just one dilemma, and I know it's a difference of 2 additional posts in the design but I wanted to check that either one is fine.
In the first image, the posts are on the outer bearers and the only problem I may run into is that I might be a little close to the slab against the alfresco and it might be an issue with concrete footings possibly being not square relative to the posts, if not, then would the span between posts be ideal?
to overcome this potential issue, I redesigned the layout to support the deck to the inside bearers and would like to know if the design would be as equally sturdy?, thanks!
I'd be happy with either of those approaches @TimGeo. For the joists with the posts connected, I'd advise screwing them to the frame instead of just using joist hangers. Joist hangers are for when the frame supports the weight of the deck, and they allow the joists to hang off the frame. In your case, the deck frame is hanging off the joists, and the joist hangers won't work too well in reverse like that. That's not a great description, but I'm fairly sure you'll know what I mean. If not, let me know, and I can explain further.
Mitchell
