How to rebuild timber stairs over tiled concrete slab?

[RickyYuan]

Hi all, I’m looking for some advice on how to fix a timber post to a tiled concrete floor.

The first image shows the old timber stairs (now removed), and the other two images show the current condition.

This area sits above a garage. The old tiles were removed, and a new screed (approximately 100mm thick) has been laid, followed by waterproofing and re-tiling.

Given this setup, what’s the best method to securely fix a new timber stair post to the floor? I’m concerned about the thick screed layer and making sure the post is properly anchored into the concrete slab below.

Any suggestions or tips would be greatly appreciated. Thanks in advance!

[JacobZ]

Hi @RickyYuan,

Thank you for your question about rebuilding some timber stairs in an outdoor area.

The attachment method would need to be able to resist any lateral forces applied to the stairs. Due to the height of the stairs and fall risks that are present with structures of this kind, it is likely something you would need to speak to an engineer or draftsperson for their assistance with the design. This is just to ensure it is done in a safe manner that is up to the relevant building codes.

As it is a concrete slab beneath the screed, then you should be able to use a post anchor with long DynaBolts or AnkaScrews to bolt the post to the concrete. Another option is to use threaded rods attached to the concrete slab using a chemical anchor such as Chemset. 

Once the anchor is bolted in place, the post can be attached to the anchor using suitably sized galvanised bolts.

Allow me to tag @Nailbag and @Dave-1 for their thoughts and insight.

Let me know if you have any further questions.

Jacob

[Dave-1]

Good morning @RickyYuan 

Now thats an interesting question in regards to anchoring the post, I would also suggest the foot of the stairs should also be anchored in the same way.

Drilling down through the screed to hit concrete and then deeper is doable and the recomendations from @JacobZ  is how i would approach it for sure.

I would do the same for the foot of the stairs. (both sides) So they dont want to splay out.

Plus when you are putting the stirrups in make sure you seal the underside so your waterproofing still stays solid.

Dave

[Nailbag]

Hi @RickyYuan 

Reading through @JacobZ instructions, I can't say I can add anything further as thats essentially how I would install the new post.

Nailbag