How to rebuild or repair a rotting deck?

Question

Hello all!

I have a small rotting deck that is attached to our house. My original plan was to repair it, but given the extent of the rotting (90% at a guess) it seems to make sense (and be more fun) to just rebuild it.

I am confident that I can build a good deck given my recent experience designing and building a shed. But I need all of your help navigating, ensuring that the replacement is built correctly, as I suspect this one hasn't been.

Firstly, there is not sufficient support underneath the centre of the deck. Secondly, there are pure timber ground contact points that need resolving. Lastly, it connects directly to the house joists as the main form of support for that side.

My understanding is that the deck should be a stand alone structure and not attached to the house in any meaningful way.

I assume it isn't viable for me to rebuild it like for like, reattach to the house joists and I should add independent supports/stumps on that side (as well as the middle) if so, where would I place the stumps? I can't put them next to the existing house stumps because that would mean digging next to the existing stumps, would I just offset them enough as not to disturb the existing house stumps? If that is the case, what do I do about the corner?

I have attached images of the current deck. It is approximately 3x3m, 2m from the ground, with the steps that are 1.4m wide.

Could be wishful thinking and I will check with my local council but I'd love to not have to get the council involved for this, if I need to get a draftsman in get a permit etc then I may just make it larger but the current plan is to rebuild as is but with modern supports.

Would love to hear your thoughts.

Many thanks!

Mike

—

The deck

The underside

The rotting bits

The house stumps with the main deck support bolted to the house floor joist.

The house side, looking a little sad. Some moisture damage, especially around the bolts it seems 😣

mikebarker · Answer

Thanks for the input chaps!

@EricL This makes sense, I'll make some loose drawings and source a draftsperson see what they think.

@Dave-1 Good to be back! The outer posts are fine, the inner centre ones that the steps attach to are rotted through. My neighbour and I was discussing adding some supports in the middle. But I don't fully understand how even with that in place we would be able to replace the side supports that the decking joists sit on, especially one that is bolted to the house joists, without completely removing the decking boards and all the top railings need replacing anyway, and the steps basically, so that's where I got to the point of let's just rebuild it.

Thanks for linking to your pool decking. That is really helpful.

Dave-1 · Answer

Good Afternoon @mikebarker

:) Welcome back!

I was looking at your photos and was thinking about what condition are all the posts in? That then led me to what condition the timbers for the rest of the deck are in? Would some more supports in the middle underneath plus some new trusses be enough to bring it back to spec? The timber looks like hardwood so even tho it may look grey and old its still solid.

I would sketch up your idea of what you want for the deck, as @EricL said it cant hurt as it will give you more of an idea of what you need to do. Even to the point of repairing it instead of replacing it.

Here are two links for my deck at home, my carpenter mate hasnt really commented to me about it other then saying "over engineered" lol But it is solid and has been for a decade and a half ish

Pool deck stage 1

Pool deck stage 2

You said you are 2m off the ground, it looks a little less than that tho if you are taking the measurement from the top of handrail, yeah it is 2m + Your local council will have rules you should be able to view of what is allowed, or either Aus or NZ rules will have it

Dave

EricL · Answer

Hello @mikebarker

Thank you very much for sharing your next project with the community. Looking at the photo you've shared with us, it appears that the deck is quite tall with sections surpassing one meter in height. Because of this it's best to check with your local council about the rules and regulations in regard to renewing your decking structure.

The advantage of having your decking plans drawn up by a professional or drafts person is that they are aware of the rules and regulations of the council and are also aware of the NCC codes. You can also tell your drafts person to draw it up as a free-standing structure. Because it's been drawn professionally it can be submitted to the council. You can still build the deck yourself but having the plan done professionally will save you the headache of having to redo it or having to take it apart due to council regulations and compliance.

In regard to your questions, yes, it's possible to move the footing of the deck so that it is not right next to the footing of the house. Its placement will depend on the concrete footing of the house and how far the deck can be cantilevered. Extra footing in the middle might be necessary, but it again depends on the materials the drafts person will use.

It wouldn't be counterproductive for you to draw a plan of your deck to show your drafts person. This gives them a much better idea of what you would like to build.

Let me call on our experienced members @Gerber, @Graeme50, @Project_Palmetto and @Dave-1 for their recommendations.

If you need further assistance, please let us know.

Eric