Is it better to line the concrete steps first with screwed down ply and then glue the new wooden step to the ply? Or glue straight onto the concrete with the new step.?
Welcome to the Bunnings Workshop community @Paul4. It's tremendous that you've joined us, and many thanks for your question.
If possible, I believe the best approach would be to screw your new steps directly down to the concrete. You could use Ramset 6 x 100mm Countersunk DynaBolt Plus Masonry Anchors. As these Dynabolts have a countersunk Phillips head on them, they will sit flush with your timber stairs.
I would advise leaving a slight gap in between the timber stair and the concrete. This gap can be established by placing a couple of washers on the Dynabolts before inserting them into the concrete. The Gap will allow water to drain and encourage airflow between the concrete and timber, preventing rotting.
Please let me know if you need further assistance or have any questions.
Hi MitchellMc, thanks for your reply.
The concrete steps are inside and I was trying to get away with no screw heads showing but that would certainly hold them down without any movement afterwards.
Are these pre-fabricated wooden stair treads? If so, perhaps contact the supplier for any documentation on how they should be fixed to the concrete staircase.
There can be incompatibilities between concrete and glues as the staircase really needs to be sealed so moisture can't penetrate the timber. I'd still recommended mechanical fixings and dowels of the equivalent timber to cover the holes.
You could line the stairs with plastic and screw strips of ply to them. You would then glue the treads to the ply as you've mentioned. Just be careful that you don't increase the rise's height on the first step because of the packing strip. A stair even 5mm too high can be a constant trip hazard.
Hi Mitchell, I’m going to finish the stringers then screw some 9mm ply to the concrete to take out the bumps making sure it’s all square and flat, but then do I glue the new step or glue and screw the new step onto the ply.?