Concrete grinding before laying floor in a converted outbuilding

[d000hg]

I've been converting a Victorian greenhouse which includes a pretty rough concrete floor. I've been procrastinating for ages what flooring to use but come to the conclusion it is going to need smoothing out regardless first.
One end is at ground level or slightly below and of course there is no damp-proofing, I used tanking slurry as shown (the far end is suspended as it's built on a slope):

There are some larger lumps and bumps at the far end. I've been considering using a concrete grinder rather than levelling compound - I have never done either before. It's slightly less than 5x3m and I have no idea how much work is involved and the size of grinder I need - Screwfix sell a hand one for £140 but I don't know what accessories I need.

A proper rental unit like this (https://brandonhirestation.com/floor-grinder-hire) looked good at ~100/day but the grinding pads cost several hundred pounds when I look more closely and I've no idea how many I actually need.

One of those cases I feel a bit out of my depth, just never using anything like this before.

 

[foxhole]

What are you converting it too?
Shallow suspended floor would make levelling easy.

 

[d000hg]

What are you converting it too?
Shallow suspended floor would make levelling easy.

See that was my original thought but seemed like more faff and I have already studded out and panelled the walls. I did consider using 2x2 resting on the concrete as 'joists'. I'm not sure what would work out quicker/easier, doing that or leveling the concrete. I can see grinding is certainly the less pleasant job

Multi function space - sort of a conservatory/garden room/playroom sort of thing.

 

[foxhole]

Joists quick and easy and allows under floor dpc and insulation .

 

[d000hg]

Joists quick and easy and allows under floor dpc and insulation .

Would it be worth just throwing a plastic DPC sheet on the slab underneath then?
I didn't really want to install floorboards as I haven't before but you're probably right. And since I'm using this project as a way to learn new skills "where it doesn't matter much if I mess up" it would be a valuable learning experience for doing the same in the house one day

Cheers

 

[foxhole]

Would it be worth just throwing a plastic DPC sheet on the slab underneath then?
I didn't really want to install floorboards as I haven't before but you're probably right. And since I'm using this project as a way to learn new skills "where it doesn't matter much if I mess up" it would be a valuable learning experience for doing the same in the house one day

Cheers

Doesn’t need floorboards , sheet of osb much cheaper .

 

[d000hg]

Doesn’t need floorboards , sheet of osb much cheaper .

Hadn't considered that, because it's a smaller space you mean?
I think the floor dimensions might actually be almost exactly 4.8x2.4m which could make that quite quick though would I want a smaller spacing as OSB is a bit less rigid?

 

[foxhole]

Hadn't considered that, because it's a smaller space you mean?
I think the floor dimensions might actually be almost exactly 4.8x2.4m which could make that quite quick though would I want a smaller spacing as OSB is a bit less rigid?

Osb is rigid , 18mm is ideal .

 

[d000hg]

Osb is rigid , 18mm is ideal .

This seems an easier option then. Like you say I can add some insulation at the same time.

Cheers