How to repair concrete steps and sandstone wall?

[khaid]

 how would you go about repairing these steps, uneven surface causes water to build up and small holes?

also, the sandstone wall has some large gaps and some of the grout is a different colour. Is it possible to re grout/render to refresh them?

[MitchellMc]

Welcome to the Bunnings Workshop community @khaid. It's terrific to have you join us, and many thanks for your question about repairing stairs.

The first thing I’d recommend is giving the stairs, sandstone and grout a thorough clean with a pressure washer and an outdoor cleaner such as 30 Seconds. This will remove moss and algal build-up and allow you to properly assess the condition, as much of the discolouration looks like it’s from growth rather than damage. Once cleaned, you might find that the sandstone wall only needs some of the grout touched up. Fresh mortar can be applied to fill the gaps, and you can add oxides to the mix so the colour blends better with the existing work.

For the stairs, you have a few options. One is to grind the surface flat with an angle grinder fitted with a diamond cup plate. This is more labour-intensive but provides the best long-term result, as it avoids the risk of a levelling compound cracking down the track. If you prefer an easier option, you could use a self-levelling compound to smooth the surface, though it may not be as durable. Another alternative is to cover the steps with timber to create a uniform look, either using merbau decking boards or pre-made merbau stair treads fixed on top of each step.

Please let me know if you have any questions.

Mitchell
 

[khaid]

This is a better photo of the stairs and stone. 
Stairs are curved and dark patches are where the water pools.

sandstone grout is coming away at the bottom but also trying to hide the pink ish grout colour.

 

[EricL]

Hello @khaid 

If you have cleaned the surface of the steps, I propose using Lanko 20kg 173 Floor Leveller. This product is rated for outside use and I suggest checking the weather to make sure that there will be a few days of sunny weather before using the leveller. Due to the size and depth of gap under the sandstone, I can only suggest using Bastion 20kg Premix Concrete. It is premixed concrete so you only need to add water to it, I suggest making a thick mix so that it will not slump when applied vertically. If too much water is added it will not hold its shape vertically. It only comes only in a grey colour and will not match your pink sandstone grout.

Let me call on our experienced members @AlanM52 and @Nailbag for their recommendations.

If you need further assistance, please let us know.

Eric

[Nailbag]

Hi @khaid 

Those diamond cup wheels @MitchellMc are very good and high-effective. But they do create a LOT of dust and wont leave smooth final finish. If you buy one, make sure it has a dual layer like this one as they last  3 times longer and more efficient. It would be good to use to square away the high-points so that should you decide to use a levelling compound, you wont need as much as they are expensive. 

The leveller compound @EricL I've used and is excellent. Though you still need to box out each tread and do a step at a time. Test the box you make with water to look for leaks. If water can leak through so can the compound.

Another thought is to simply have the steps professionally coated with something like exposed aggregate. Then you wont have to do any prep.

Nailbag