Creating wooden frame for outside concrete bar top

[Deep86]

Hi all,

I was watching this YouTube video recently and he managed to sell me on the idea to make my own concrete worktop for a bar area in the garden.

I am a complete novice at woodworking so it'll be one hell of a learning process.

I'm planning to make a top that is 160 x 80 x 5cm, this size will make the top weigh around 154kg! So I need something very sturdy to place it on.
In the video he used fence posts to create his supports, I'll be using 10x10cm treated fence posts as my legs as well.

Because of the weight of the top should I use 6 legs?
For the mortice joints I'll assume I need to stagger them in height? The left portion of the table, the bottom brace is 10cm off the ground while the section on the right is 15cm off the ground.

My only issue with the mortice joints is that it might look a bit silly as it's not all in line, is there another type of base I could create instead that would be as strong?

Thanks for all your help!

 

[Deleted member 174758]

Not necessarilly, instead I'd rather have four (or six) legs connected at the top by timber rails, like a pine table would be, and maybe some cross bearers. That way the rails/bearers will take the load an reduce any chance of the top cracking. Don't know if the video shows it, but the best stuff I've used to make smooth concrete forms is melamine faced chipboard - leaves a lovely smooth surface. Just remember that when you strike the mould you will need several bodies with you to turn the top over and manhandle it into position

 

[foxhole]

5cm seems thin unless reinforced with mess .

 

[Deep86]

Not necessarilly, instead I'd rather have four (or six) legs connected at the top by timber rails, like a pine table would be, and maybe some cross bearers. That way the rails/bearers will take the load an reduce any chance of the top cracking. Don't know if the video shows it, but the best stuff I've used to make smooth concrete forms is melamine faced chipboard - leaves a lovely smooth surface. Just remember that when you strike the mould you will need several bodies with you to turn the top over and manhandle it into position

Could I put a piece of timber between all legs, (A & B as in the below picture) and just screw them in from the sides?

Or would a mortice joist be the best method?

Yeah I'm not looking forward to turning it over, but I'll have help from a few mates. I'll also be using melamine boards like the guy in the video

5cm seems thin unless reinforced with mess .

I'll be putting in a 10mm rebar mesh in the concrete mix. That should be enough to strengthen the top (I hope!)

 

[Mr Chibs]

Don’t know if it’s correct, but I was suggested to use grano dust mixed with cement... as the final finish is better.

It’s on my list to try and make a concrete worktop, but haven’t got around to it.

 

[foxhole]

If you want a smooth top it can be polished .