Hellooo!
I’ve got a little project I’m about to start and will be picking up the wood tomorrow. But I thought I’d ask here if anyone has any knowledge or advice on what I’m about to do.
Does anyone have much experience/knowledge about concrete?
I have a plan to create a concrete/wood desk top (around 1220 x 530mm). The aim is for it to look and feel like concrete but I’m trying to keep the weight down. The idea is for the top surface and all around the edges to be a thin layer (maybe 5mm) of concrete and the core/bottom to be some sort of lightweight wood sheet material (maybe 12mm). So the total thickness of the desk will be around 17mm.
To create a mould I would have a big surface of wood and 4 strips for the edges. I would pour in a 5mm layer of concrete and then place the 12mm thick sheet of wood on top. The wood would be around 10mm smaller (width and length) to create a 5mm gap around, which is where I would then pour concrete in to the same level as the piece of wood.
The issue I foresee are that the wood might sink. So I’ve thought of a couple options…
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Wait for the first layer of concrete to dry and then place the wood on top and pour more concrete round the 5mm edges/gaps. But would the concrete edges stick to the concrete surface once it’s dry? Or maybe it could be partially dry?
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If I make the edges of the mould the exact same height of thickness I want for the desk top (17mm) and I attach a couple long bits of wood on the wood that might sink, and rest it on the edges of the mould then it would stay in the right place. I can’t really see a problem with this idea, just a bit more of a faff.
The other concern I have… because I’ve never worked with concrete and I have seen a lot on youtube they always use a metal wire mesh inside the concrete to give it structural integrity. Would I need something like that even though it will be 5mm thick and be resting on a wooden surface? Or how about if I went even thinner 3mm? Better or worse?!
Also… one side of the desk would be the drawers I made below which are very solid…
And the other side I’m planning to build two legs out of some 12mm thick left over ply like this guy…
Which is why I don’t want the desk top to be too heavy.
Any advice much appreciated!!
Matine