Need a bit of help.

My house is about 4 feet higher than the roadway, with a raised front garden and a sloping asphalt drive way.

The access to the house is from the driveway, and even allowing for the slope there are still two steps up to the path at the top of the garden which are both about 15″ high, and too high for my dear old mum who is disabled to get up on her own. They are however deep enough (big square paving slab size) that I could halve the height of each by building in new steps on the existing ones to fill in the gap.

The lower one would be onto the asphalt driveway and would be wedge shaped so it’s level at the top but where the driveway slopes. The other would be onto the paving slab.

My plan is to cheat and use postcrete – make an appropriately shaped bit of shuttering to held the dry mix and mix it in situ, making it a bit proud so I can then drop a half width slab on top while it’s still a bit wet so it matches the existing steps. Will it work, do I need to do anything to make it key onto the existing surfaces and will it grab the top paving slab well enough?

I would have thought that would work OK but I can’t see there is any saving over doing it properly. It should stick to the ground just fine, I’d be wary of how well it sticks the the slab. If it settles a bit as it goes off then you will have a cavity under the slab.

personally I’d let the concrete go off a bit (which will be pretty quick with postcrete) then lay the slabs with a full bed of mortar.

I can’t see there is any saving over doing it properly

Laziness / convenience / avoid hassles of hand mixing concrete and clearing up.

Point taken on using mortar to stick the slabs on after though.

Could always use some standard concrete blocks laid flat to make up the step height – 2 courses of 75mm blocks laid flat + a bit of mortar should get you to roughly the right height so that when you top them with a slab you’ll get to half of the existing step height. Take out any slope of the driveway under the lowest step with a thicker bed of mortar under the lowest block.

I would say that Postcrete is far too fine a mix for the depth you need to build up and would crumble away over time. Either make up a decent mix with ballast/dust and cement or do as tonyplym suggests.

Can’t you make some nice steps out of wood?

Postcrete goes off like **** and if any of the edges are subsequently seen when you remove your shuttering I’d guess at it being honeycombed to ****!