How to replace decayed decking?

We intend to replace decking about 12 meter sq. Photos attached.
please let us know if your are running any related weekend workshops in Broadmeadows/Craigiebun bunnjngs. Ali looking for some videos that could suggest us material and tools required to complete DIY task. Thank you.

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MitchellMc

Welcome to the Bunnings Workshop community @smhasnain. It's great to have you join us, and many thanks for your question about replacing decking.

You typically won't find in-store workshops on replacing decking. However, you've come to the right place, as the Bunnings Workshop community is filled with knowledgeable members that can assist with your project. You might like to have a look at this previous discussion by @darrenh on Replacing a low-level deck. They replaced a decayed deck with Ekodeck and achieved some sensational results. I'd suggest looking at Ekodeck, as it is more resistant to decay than timber decking and doesn't require yearly oiling. If you are unsure what decking boards to use, check out this helpful article on How to select decking timber.

For replacing the damaged boards, this guide on How to renovate a timber deck will be useful.

You'll need to remove some boards with a wrecking bar to get an indication of how involved this project will be. Hopefully, this project will only require you to remove and replace the decking boards. However, I suspect you're going to find that the deck structure has begun to decay, especially in that step area. You'll need to repair or replace any decayed timbers in the frame before relaying the decking. Not to worry, though, as we can guide you through that process too. Upload some images of the deck frame once you've removed some boards so we can advise on the next steps.

For relaying the boards, you'll require a drill driver, which you'll use for the decking screws, and a circular saw will be needed for cutting the decking boards to length. Please remember your PPE when disassembling the deck and reinstalling the boards, including safety glasses, gloves and a face mask.

Please let me know if you have any questions.

Mitchell

smhasnain

https://www.workshop.bunnings.com.au/discussion/comment/26505#Comment_26505

Thank you Mitchell for your detailed response.
Just two quick questions:

what is the best way to remove top boards (that are secured with nails on timber frame), so structural timber is not damaged. As I do not want to change the framings.

Do you suggest to use composite material or Protechwood Proshield as board over merbau decking.

Thanks

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/75918#Comment_75918

The best way to remove the boards, @smhasnain, would be to pry up one end with the wrecking bar and then make your way down the board. At each joint where there is a nail, insert the wrecking bar between the decking board and the timber joint. Lever up on the board to ease the nail out of the joist. To save some time, you can use the circular saw to cut in between the rows of nails, reducing the decking boards' length. The smaller sections of the decking board should be easier to remove than longer lengths. Make sure not to cut through the joists whilst doing this.

Your decking boards are heavily decayed, much more so than I would expect on a dwelling that doesn't appear all that old. I'd suggest a high humidity level within the deck structure is accelerating its decay. Composite decking will be far more resilient than Pine decking and also Merbau decking. If the current decayed decking is hardwood like Merbau, then I would suggest you switch to composite decking. If the current decking is Pine, I'd suggest you switch to a hardwood like Merbau or composite decking.

Mitchell

smhasnain

https://www.workshop.bunnings.com.au/discussion/comment/101803#Comment_101803

Thank you for your great reply.
how do i know whether existing deck is Pine or Merbau?

The current deck board is 17x90mm, shall we go for the same size or go for larger board?

How we can put the screws from the side of board into the frame, so screws are not visible.
thanks

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/117873#Comment_117873

Hi @smhasnain,

If you were to cut a length of timber and show us the inside, we could likely determine if it is Pine or Merbau. Pine is lighter, and Merbau is deeper red/brown-toned timber. Merbau is a hardwood that doesn't dent or scratch easily.

The width of your board is up to your personal preference. Having a wider board is typically considered more luxurious and provides a more spacious and modern look.

To conceal your screws, you can countersink the holes so the screw head is recessed below the timber's surface. You can then fill over the screw head with Merbau-coloured timber filler.

Please let me know if you have further questions.

Mitchell

smhasnain

https://www.workshop.bunnings.com.au/discussion/comment/127245#Comment_127245

Hi Mitchell

After having great advice from you, I have started work on to replace decayed deck at step area (refer attached Image 1 as a beginner When I removed a couple of lengths of decayed decking boards at the step area, I found that the deck structure has begun to decay (refer attached Image 2).

Although I relayed the 70mm Merbau decking boards temporality over this substructure but intend to do it properly. I used a drill driver as shown in Image A and Macsim 8G x 50 SS Decking Screws. Which brings me a couple of Questions and looking for a cost effective and less laborious options.

Q1: My current decking structure is more than 18 years old. Do you recommend changing the substructure at this stage, if yes then what sort of timber, nails/screw I can use it for this external decking. In this situation any suggestion to rebuild the substructure is highly appreciated. Do I suppose to put any protector over timber?.

Q2: How I can remove joist hangers to separate timber pieces (refer attached Image 3).

Q3: When I was inserting the Macsim 8G x 50 SS Decking Screws specially at the edge of the board by using drill driver (as shown in Image A) then it cracked the board (refer image 4 and 5) and even I damaged the board when inserted the screw (refer attached image 6). Do I need to do a pre-drills pilot holes at each point before I put a deck screw or else? Please kindly guide how I could avoid cracking or damaging of boards and able to finish off as even and professional finish.

Q4: Do I require any spacer between the two 70mm boards length during installation?

Q5: Do I need any sealer or decking oil or appropriate color to put on the decking board after finishing the installation.

I would highly appreciate your appropriate guidance and any other relevant advices.

Much appreciated. Syed.

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/133478#Comment_133478

Hi @smhasnain,

The step frame appears to be starting to decay, and I'd suggest that now would be the best time to replace it. Hopefully, the frame in the upper deck section doesn't need replacing. I'd suggest using the same size H3-treated framing timber that is there currently. Joist hangers can be used, or you might like to screw the sections together with treated Pine screws. Given you've experienced this decay, it might be best to paint the underside and sides of the timber with bitumen paint.

To remove the timber frame, I'd recommend cutting it up with a saw, as it would be difficult to remove the joist hangers.

Those screws need to have holes pre-drilled and countersunk, and you can use a pilot drill/counter-sinking bit for that. Alternatively, you can switch to self-drilling decking screws. The Zenith 12G x 50mm Stainless Steel Self Drilling Decking Screws - 500 Pack would likely be the best value for money.

You will need to space your decking boards. Since there has been some decay, I'd go for at least a 5mm gap between them. This slightly larger gap will help provide airflow to the deck structure. These decking spacers will come in handy for keeping the gap consistent.

You need to age the timber, which strips out the Merbau tannins before oiling. I'd recommend leaving the deck to naturally weather for eight weeks or applying a new timber prep solution to accelerate the process. Once the deck has aged or you use the product, you can apply your decking oil.

Please let me know if you have further questions.

Mitchell

smhasnain

https://www.workshop.bunnings.com.au/discussion/comment/137270#Comment_137270

Dear Mitchell

Thanks for your great advice.
I am progressing on the project. Last sunday I bought some decking related material from Bunnigs. You have advised me to use Bitumen paint to protect the timber from rain water. I was about to buy your recommended paint and thats is going to cost me ~&20. A guy from Bunnings has advised me that instead of getting smaller container of Bitumen paint in $20, i may purchase a 15L Betta Cemseal & Fix (photo attached) on discounted price of $6. I bought that sealed bucket. After reaching home, I have noticed following even without removing the seal of the bucket. (1) strong smell of solvent (2) felt some thing is settled solid in the bucket. When I tilt the bucket I felt something in a solid form in one piece and that single solid piece moving away from internail surface of the

Bucjet. i am not sure whether i can remove the bucket seal and look inside bucket or just return the bucket to Bunnings and will get Bitumen paint that you have suggested for water proofing.

Please advice me whether i can use Betta Chemseal & Fix from the above reffered bucket instead and whether it is easy to apply on treated timber frames or and concrete (under deck) in comparison to Bitumen paint. Please also let me know whether the material in the bucket is expired or not.

Look forward to hearing from you.
Thanks

syed

EricL

Hello @smhasnain

I suggest returning the Betta Chemseal if you suspect that it has gone off and is no longer in good condition. I propose staying with @MitchellMc's recommendation of using bitumen paint.

My best advice is to make sure that the timber is totally dry before you apply the bitumen paint. You don't want to trap any residual moisture in the timber as this will only accelerate its deterioration.

If you have any other questions we can help with, please let us know.

Eric

MrSober

https://www.workshop.bunnings.com.au/discussion/comment/139903#Comment_139903

I would assume this bucket of Betta cemseal would have been sitting on the shelf for an extended period of time hence the discount, these usually have an expiry date or something marked somewhere. It could be that is just needs a good stir but maybe if something feels too solid it would be best to just return.

I would also recommend a product like this to put on the top of the joists before laying the decking boards down. https://www.bunnings.com.au/protectadeck-45mm-x-50m-flexible-pvc-joist_p0910783 As it looks like that step for one would be prone to copping alot of rain, there are other styles that are cheaper like a type of tape etc. Could be worth also seeing if the frame can be raised a little more off the ground if it is in direct contact with the soil and concrete.

smhasnain

https://www.workshop.bunnings.com.au/discussion/comment/141722#Comment_141722

Hi,

Thank you for providing me a continuous and great support and timely advice. My apologies, I would have a couple of questions below:

(1) I will use Protectadeck material between the deck and joist in front step area as suggested. Do I require to use liquid nail or just nails to secure Protractadeck material between the deck and joist. I intend to raise the frame just <1cm from the concrete. In this new setup, do I still need to cover bottom frame in the step area with Bitumen as advised before or no need for bitumen.

(2) I have attached a couple of photos, to demonstrate the condition of joist of the rest of the decking area. Do you suggest, I must change all the joist in that area or they will be okay. If you suggest to change all joists then please advise how I can remove joist hangers between the joist and beam, so joist can be replaced. What type of timber and its dimension for joist i would require to use.

(3) Do you suggest to change 5 front timber footings/supports

(4) Any other advice would be highly appreciated for economical way out for laying down this deck.

Much appreciated.

Syed

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/143094#Comment_143094

Hi @smhasnain,

I think the timber is borderline needing to be replaced. There is a certain amount of weathering, and this will only continue to get worse over time. If you're going to the expense of installing new decking, then it would make sense to fix it over new framing and joists. With the decking removed, now is the time to consider whether you'd like the new deck to last 5-10 years or more than ten years. There are signs of weathering but no obvious areas of decay. If there was decay, then I'd 100% recommend you replace the timber now.

To remove the current joists, you'd cut through them in the middle and use them to lever the Pryda nail fixtures off. If they are stubborn, you can use a prybar to remove them. It appears that 90 x 45mm H3 Pine has been used, and I'd stick with that for replacement.

Protectadeck is installed by laying it over the joists and stapling it into position.

Adding bitumen paint to the underside of timber, whether it's raised or not, is of benefit. The closer the timber is to the ground, the more important it is to coat the underside.

Please let me know if you have further questions.

Mitchell

MrSober

https://www.workshop.bunnings.com.au/discussion/comment/143094#Comment_143094

Would agree seeing you are already at this point it would be easier to replace now than at some point having to pull all the decking boards back up and replace at a later date. But if money or time is a factor you could leave it all open like this for awhile to try and get it all as dry as possible, see how your levels look etc as you may have to plane the tops a bit if they are warped. You could then use the same bitumen stuff on them to help keep the moister out.

Is it worth putting something down on top of the soil to lesson the moisture rising?

smhasnain

https://www.workshop.bunnings.com.au/discussion/comment/144051#Comment_144051

Hi,

i have installed ~ 12 meter square surface area new Merbau deck, 3 months ago. Please refer uploaded images.
i would like to know the following:

(1) Is it right time to apply either oil or stain? Which one is preferable and dconomical

either oil or stain?

(2) how should I prepare new 3 months old deck, before any applications?

(3) what essential tools and material (quantity), i need to buy from bunnings to complete this project.
(4) How soon i can walk on the deck after proposed applications.

Thank you.

smhasnain

https://www.workshop.bunnings.com.au/discussion/comment/144819#Comment_144819

Can i please get some advice from Bunnings on my previously posted questions regading oiling the new deck. Thank you

EricL

https://www.workshop.bunnings.com.au/discussion/comment/145367#Comment_145367

Hello @smhasnain

Your deck looks very well-seasoned and it's just about the right time to oil it. The general steps are to clean the surface of the deck with Cabot's 1L Deck Clean or similar in combination with an Oates Long Handle Deck Scrub Brush. If you're going to use a pressure washer, just make sure that you have it at its lowest setting to prevent splintering the surface of the decking panel. Once the deck has been properly cleaned and is totally dry you can then begin oiling the surface.

Here are some handy step-by-step guides:

A good example of a decking oil is Cabot's 4L Merbau Aquadeck Exterior Decking Oil. It is a highly durable, low odour decking oil that provides exceptional durability to all exterior surfaces and lasts twice as long as traditional decking oils. Aquadeck's advanced dual technology allows natural oils to penetrate and nourish timber, creating a durable acrylic barrier for a beautiful natural finish. It is ideal for use on decks, garden furniture, pergolas, fences and gates.

One factor that greatly affects drying time is the weather. The colder it is the longer it will take the surface to dry off. In ideal weather conditions the surface should be touch dry in 4 to 6 hours, it should be safe to walk on in 12 hours and you can put your furniture back in 24 hours. However, this will depend on the prevailing weather as I mentioned.

I propose using your best judgement and if it still looks soft or wet, I suggest using another entrance for the meantime until the surface is dry and solid.

If you have any other questions we can help with, please let us know.

Eric

smhasnain

https://www.workshop.bunnings.com.au/discussion/comment/145791#Comment_145791

Thank you.
Does 1L Deck Clean and 4L Aquadeck will be sufficient to cover 12 meter square area?

EricL

https://www.workshop.bunnings.com.au/discussion/comment/146115#Comment_146115

Hi @smhasnain

The Cabot's 1L Deck Clean is rated to cover 10 square meters. If applied judiciously, you should be able to extend it and cover the remaining extra two square meters. The Cabot's 4L Merbau Aquadeck Exterior Decking Oil is rated to cover 24 square meters with two coats.

If you need further assistance, please let me know.

Eric

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