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Building a low-level deck over concrete

DIYImpressions
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Building a low-level deck over concrete

Preview of the finished resultPreview of the finished resultHello Team, i plan to build a deck outside within the shed area over concrete area.

 

Dimensions are 8 meters x 3 meters. Ground clearance at the entrance  (left side) is 120mm but on the right side window clearance is 170mm.

 

I want to build a deck with merbau 140mm running to parallel to house with picture frame design. 

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Also i want to lay pebbles at the edge of decking like this

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I have read the “Building low clearance guide” and want advice on lengths required to start the project. Appreciate your guidance. Thanks

Re: building a deck

Hello @DIYImpressions

 

That is the ideal setup for the AnkaScrew's. You can use Ramset 12 x 60mm Galvanised DynaBolt Plus Hex Nut Bolt. I don't recommend getting anything shorter or thinner than this. I recommend using a washer when installing a Dynabolt.  If you are using the Cup Head Bolt and Nut you will only need to use a washer on the nut side. However, if you use the Hex Head Bolt and Nut washers will be needed on both sides.   

 

If you need further assistance, please let us know.

 

Eric

 

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Re: building a deck

Thanks @EricL Washer is added in the list on both sides with Hex Head Bolt and Nut.

 

This design can support how much weight? Can it take 3000kg? 


Regards,
Nauman

Re: building a deck

Nauman (@DIYImpressions),

 

Did you want to know how much weight the whole deck could carry? If it is designed to the building code  AS1170:2002 it can take 1.8kN or approximately 180kg per square metre.

 

Were you going to place anything on it that might exceed those specifications? 

 

Mitchell

 

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Re: building a deck

We plan to have 14 adults (during gatherings) with outdoor furniture, bbq kettle and standing heater. My estimate is 2000-3000kg. So with the plan we have drafted, ideally it should take that. 

Re: building a deck

Hi @MitchellMc @EricL 

 

Questions on washers:

- The washer placement is on the head side or nut side when using Zenith M12 x 65mm Hot Dipped Galvanised Cup head bolts and nuts for mounting joist to angle bracket?

- You recommended using washers with dynabolt on both sides. I assume this is one below the angle bracket and one above the bracket?


I mistakenly ordered Zenith M12 x 65mm Hot Dipped Galvanised Hex head bolts and nuts instead of Cup head. Is that fine?


Regards,
Nauman

 

Re: building a deck

Hello @DIYImpressions

 

When using the Zenith M12 x 65mm Hot Dipped Galvanised Cup head bolts and nuts, you only need a washer on the nut side. I recommend only one washer for the Cup head bolts and one for the Dynabolt. It's ok if you've made an error in your order, you can return this product and order the other ones that you need. Please remember that with the Hex Head bolts, you will need two washers (one on each side) to mount the bolt to the angel bracket and timber.

 

If you need further assistance, please let us know.

 

Eric

 

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Re: building a deck

Thanks @EricL 


Got my tools and timber today and will start laying the foundation from today.

 

I saw the specifications of Ramset 10 x 60mm AnkaScrew Masonry, and they have a special washer face attached to it. Do I still have to use M10 galvanised washer?

 

My other concern is with using Camo Fasterners. I have a feeling that they may intervene with bolts passing through joist. As I am using 5 angle bracket per joist, possibly at 5 locations I might face this problem. What are my options here? Reason I am going with Camo to have a smooth finish. What if I go with discrete top screws? Can you recommend any?

 

And what is the recommended screw space on the deck boards?

 

And do I need pre-drilling for mounting Cup bolts into the joist and the same for Merbau deck? 

 

Thanks

Re: building a deck

Hello @DIYImpressions

 

Moving the angle bracket one or two centimeters to avoid the Camo Fasteners should be ok. It's always good practice to put a washer on just in case the head does not cover the entire hole of the angle bracket. I'm afraid the Camo Fastening system is the only one I know that can hide the way it's driven in. There is the Buildex 10g x 65mm Self Drilling 304 Decking Screws - 100 Pack. It's specifically designed for fixing hardwood and softwood decking boards to softwood timber floor joists for a flush finish. No pre-drilling or pre-countersinking. Quick Drive Point allows optimum positioning and prevents timber from splitting. However, it will be seen from the top as this screw only has a low profile discreet head.  

 

You will need to predrill for mounting Cup bolts into the joist. If you are screwing from the top and not using the Camo Fastening system, I suggest placing the screws no closer than 15mm from the edge of the decking panel. Please note that if you do screw in from the top you will need to predrill all your decking panels.

 

If you need further assistance, please let us know.

 

Eric

 

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Re: building a deck

Thanks @EricL 

 

which pre drill bit size should I use for M12 x 65mm Cup head bolts? I guess it will be 12mm wood bit, right?

Re: building a deck

Hi @DIYImpressions

 

The 12mm wood bit is the one you need to use to fit the M12 bolt into the timber. You can match them up side by side to make sure that the size is correct.

 

Eric

 

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