How to install timber decking over concrete slab?

[matimbo3011]

Hi Community,

My front of house has 2 x stairs/landings which currently are tiles on a concrete slab, pic below.

I'd like to replace the tiles with timber decking. I'd also like to widen the stairs and platform - e.g. the stairs on the right would be widened on both side to where the plants currently are, and ame for other stairs/landing on left. The widened sections would be supported by posts concreted into the ground, but I am hoping not to have to remove the concrete slab. I have seen from other threads that it is possible to lay timber decking on top of concrete but there needs to be space underneath for the battens plus a non-wood packing spacer. The current tiles are 20mm thick versus standard timeber decking 19mm thick (I think?). So after I put battens and a spacer underneath it will be higher than the current levels. I think it will be OK if the final height is a bit higher than current, but not too much. So my questions are:

What would be the min batton height I could use?

Would the longevity be better with synthetic vs timber given the limited space underneath?

If I need to, is there a way to reduce the height of the concrete slab just enough without full removal i.e. like planing down wood?

Anything else I need to be aware of?

I am undecided if I'll do this myself or get a tradesman. I did get one quote already who insisted he needed to demolish all the concrete slab at high cost.

Thanks,

Tim.

[EricL]

Hello @matimbo3011 

Welcome to the Bunnings Workshop community. It's sensational to have you join us and thanks for sharing your question about installing timber on your concrete steps.

I understand your desire to have timber over your concrete steps. In my opinion it feels better under the feet. However, looking at the picture you posted, I'm afraid that there is not enough space to install a frame and timber decking over your concrete steps. For example, if you were to use a 70x45 timber frame plus the decking panel you would be looking at 89mm. This does not include the air gap you'll need underneath. 

It would be counterproductive if the concrete steps were trimmed down. It would be difficult to relevel the concrete steps and the surface would not be uniform. 

Having the frame so close to the surface of the concrete steps will negatively affect the frame as moisture would get trapped between the concrete and timber and shorten the timber frames life. I agree with the trade persons suggestion, demolishing the concrete steps will give you the freedom to design and create the timber steps you are after. To save money on the project, I propose doing the demolition yourself and then asking for a quote for a timber step frame. You can then cover it with timber decking panels.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you need further assistance, please let us know.

Eric

[Dave-1]

Good Evening @matimbo3011 

I really prefer timber steps myself, something about the way they feel and the grip they have

Sadly I also agree with the quoters suggestion about removing the steps. I also agree with @EricL that you should be able to do it yourself and I would seek a second quote to just install new steps/decking as you want. BTW Bunnings have stair kits that seem very easy to use. stair kits show a whole range of them that you can use while considering a quote.

I did notice that the second set of steps end at a different height? It makes me think that even if you managed a stringer of some kind that sits over the steps and connects to supports away from the steps so the beam dosnt touch you would still have an issue with the two opposing heights. Are both the step heights themselves level with one another?  The complexities of trying to accomodate the steps, the space you are working in is why I am suggestiong removal and replace.

Dave

[Nailbag]

Hi @matimbo3011 

I agree with @EricL being that the easiest way to obtain what you're after would be to simply demolish the existing concrete and tiles steps and replace it with the wider timber ones. A decent local handyman could build this for you if it was out of your level of expertise.

Nailbag

[matimbo3011]

Thx for the quick response Eric. I kinda expected that would be the outcome but good to get an experienced confirmation.

Cheers,

Tim.

[matimbo3011]

Thanks for the input Dave, much appreciated. Re the differrent heights of steps, yes correct. The block has a slight slope. I'm not intending to join them into one, rather just want to widen each a bit but there still will be a gap between so hopefully the difference in height will not be too noticaeable.

[matimbo3011]

Thanks for the input Nailbag, much appreciated.