How to leave the decorate formwork embedded in a new concrete floor?

[willem]

i want to pour a concrete floor in smaller sections and leave the (decorative) formwork embedded in the floor. any tips or suggestions?

[Spud_Mc_Fuddy]

Where is the floor? In a home or garage or outside? You would want to use something rot resistant and make sure that you didn't go down below your minimum slab thickness if applying for consent for the job. Also, putting down a membrane would be a good idea to prevent water causing the timber to swell and shrink at a different rate to the concrete and possibly cause cracking?. Tannins could also possibly leach out of some hardwoods and stain your concrete. Would it be possible to sink a temporary piece of well oiled box grade timber in as you were laying the floor, perhaps even wrapped in polythene, then pull it out and replace it with something slightly smaller and epoxy that in? You could possibly wire it down to insulation chairs. Also you would need to make sure it didn't bend during installation. There are also tiles that look a lot like timber you could possibly embed in the concrete. Not sure what final effect you are after though.

[Akanksha]

Welcome to the Bunnings Workshop community, @willem. We're delighted to have you join us and many thanks for your question.

Great to see you've received advice from @Spud_Mc_Fuddy. Our resident Bunnings D.I.Y. expert @EricL will also be happy to provide further advice on how to proceed with this project as soon as possible. Also tagging @CSParnell and @diy_hausdesigns to see if they have any thoughts. 

Let me also extend a warm welcome to @Spud_Mc_Fuddy. It's a pleasure having you join us and many thanks for jumping right in to help our members. 

Akanksha

[CSParnell]

You might benefit from adding a textured wood grain plank pattern to the form work that way when it is removed you are left with a pattern.

Just a thought

[EricL]

Hi @willem 

Thanks for sharing your question about pouring a concrete floor and leaving the formwork in place. Can I please request for you to draw up the formwork you are planning to leave in place? Can you also please tell me what kind of timber you are planning to use? It is technically possible to leave the formwork in place, but there is always the possibility that the timber would warp due to the moisture being released by the concrete.

In order to keep the look you are after, I suggest using ordinary form work and then replace it with the timber you were planning to use. I understand that you are probably trying to minimize handling, but this is the safest way to do it without running the risk of timber warping. 

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

Eric