How to attach a deck to uneven sandstone rocks?

[JHerbst]

Hi all,

Long time lurker here. Im in the process of planning/building a small low level deck (more like a path).

7m long, 2m wide.

One side is dirt where I can dig plenty of holes, fill them with concrete and place stirrups. The other side is sandstone and unfortunately not flat enough to bolt a bracket on and given the slight height differences over the 7m (less than 100mm) I need something to aid with that. I was hoping to drill into the sandstone (huge blocks) and chemset threaded brackets at the needed height to it. Couldn't find a suitable product though.

Anyone with another great idea?

Thanks for your time,

Jannis

[Dave-1]

Good Evening @JHerbst 

Now that sounds like nice project to figure out!

First up, any chance of a few pics of the general area and specifically the slope of the sandstone?

I did have an idea on how to attach brackets to the sandstone, You pretty much hit on it yourself.

Drilling a hole in the sandstone and then using these Ramset 12 x 100mm Galvanised AnkaScrew Masonry Anchor to attach a Right angle bracket, I just choose one at random to explain. Carinya 100 x 125 x 25 x 6mm Black Heavy Duty Manhattan Angle Bracket - single - Black 

that you can then attach your crossbeams to.

With sandstone Id be tempted to only drill one hole into the sandstone and use the masonary anchor as two close holes and screwing in could cause a fracture. As for a flat area, you could use a cold chisel and a hammer to "smooth" the base where the bracket will be and then bend the bracket to the right angle that you will need.

I did go for the longer anchor screw for this reason, also please make sure the hole is deeper then the screw and empty of grit before you screw the anchor in. I "thought" I had... needless to say one new ratchet driver needed... 

I am sure you have been checking out all the decking info I am actually going to test drive a very low slatted deck and see how it travels with the weather, but thats another story.

Dave

[Jewelleryrescue]

Hi @JHerbst 

You  can always  use a  matoch and chip the sand stone down.  Or  hammer and chisel  or  a rotary hammer drill and  chisel point.

Sand stone is easy to work  with.

[MitchellMc]

Welcome to the Bunnings Workshop community Jannis (@JHerbst). It's fantastic to have you join us, and many thanks for your question about attaching a deck to sandstone.

As @Dave-1 has mentioned, some images of the area and the locations you'll need to mount to would be helpful for our members when determining effective solutions. Let me know if you need a hand uploading images. Also, can you please let us know the total height deviation over the length you'll need to deal with? That will give us an idea of what brackets can be used.

I like the ideas presented and @Dave-01's suggestion of using a bracket similar to this Carinya 150 x 150 x 75 x 6mm Hot Dipped Galvanised Angle Bracket. You could possibly also use these Pryda Post Anchor Bolt Down w Washer 90mm M10 with washers on the threaded anchor studs to level the base.

Please let us know if you have any questions.

Mitchell
 

[JHerbst]

Thanks for your reply.  Great idea to chisel it flat, I will give that a test and see how I go. There is no real slope from start to end, it's rather a deviation in height on each sandstone block or from one to the other. Over the entire 7m span the biggest deviation is about 100mm (getting this deviation to show in a photo is tricky but I will try).

[Dave-1]

Morning @JHerbst 

Tell me about it! lol When I was trying to work out the slope for a path at home I was scratching my head, but then thought -

Straight piece of timber, place your level on top. Then lift the timber until its level, you then have the length of your timber (you can mark  1m) and meausure the drop at that point. In a photo seeing the level piece of timber with the slope would also work well.

Dave

[JHerbst]

I think I'm going to stringline it over the weekend leveling it at the peak so I can accurately measure the dips and decide on the right solution/bracket.

[MitchellMc]

Give us a shout when you have those measurements, and we'd be happy to help you select the right height brackets @JHerbst. 

Mitchell