Do you have any fit bodies that could use a DIY concrete grinder from a hire shop? It looks like it would be a weekend of very dusty work but would give a clean base to re-coat. There are coating products available at Bunnings but I’d look to buy in bulk which you can do. Search Professional coatings and/or Industrial coatings for online suppliers but I’d heard to your local paint shop for some recommendations.

Looking at the pictures , it looks like it was the parts area of a workshop , not an actual workshop , with hoists and the like ? Why I ask is to determine how much cleaning is neccessary ? If oil has soaked in , now matter how good your coating is , it won't bond correctly .

I part-own a motorsport business , and we use a specialised concrete cleaner ( I'm in NZ , so brand names woill be different ) , but basically we get 20 litre or 200 litre containers , and it is very strong -- you brush it on using a yard broom ( and breathing appartus ) and it bubbles and smells , and all this brown muck ( oil and dirt ) settles on top -- leave it 30-60 minutes then waterblast ( a tip is to use a deck cleanring attachment on your blaster -- it cleans at least as well as a straight waterblaster , but also cuts down on splatter ) .

As bigreader says , you might need to use a commercial concrete grinder or an agle grinder or wire brush or a spade or a wide chisel and hammer to get everything smooth . If there are cracks or similar , you might even need a skim covering of concrete -- I'm not an expert , but I suspect going around with a drill and drilling holes for the new covering to cling to would be worthwhile .

For coating , we use specialist companies -- they use a 2 or 3 pack product , I'm almost certain it is epoxy based , as it is called 'seamless' , so basically it sets hard . We get a flecked look in about 3 shades of charcoal , and a matt grit finish , maybe similar to 400 grit . Is the building still going to be a workshop ? Obviously , any concrete paint ( like a driveway paint or similar ) will tidy things up -- as a general rule , the more you spend the longer it will last . So something that is basically house paint is cheapest , but nastiest . The companies we use might be $20k , but we get 6 or 8 years of heavy use , whereas $500 of paint will probably start wearing around doorways etc in 6 months .

Very good advice on the cleaner Pottsy. I’d forgotten about those products (straight to the gadgets machinery for me). Def worth a try for the OP.

Just another thought ( I don't know enough about your intended use to say its a suggestion ) --

If it isn't going to be a full-on workshop , and you just want the floor tidier , Bunnings and the likes have those fairly cheap and nasty stick-on floor tiles -- I think a pack of 9 of 300x300mm ( so nearly 1 sq mtr ) is from memory $12 , maybe even less . For a workshop , I'd suggest also getting a 4 litre of good glue , and a $2 brush

I've used the black and white ones in a retro themed showroom a few years back , and they are passable as far as look and quality goes . The main advantages are you probably don't need the floor prep as good , and if it is an owner occupied workshop , you can do maybe just a 900mm wide strip this month , 600mm strip next month , etc -- as finances go .

Thanks big reader. We two 60ish workers are worn out from cleaning and painting the walls/pegboard, and scrubbing the dirt and oil from the floor, so we are not up to concrete grinding.

Our SIL wanted to lay vinyl/hibrid planks but now realises the difficulties in this large space. We are trying to find a short term fix to get the space looking ok, so we think a coat of paint might do the job.

We are located in a small town in Central Qld so there is limited supply of material and equipment making the job even harder.

Thanks also to Pottsy. You are correct the space was an Auto parts sales & repairs for many years but not used for maybe 10 years.

The space will now be used quite differently as a multipurpose space for office and recreation faciliry for NDIS support service in regional Qld.

It is hard to find a builder out here to add walls to separate the large space into different areas. First step is to try to get the floor coverage the same colour at least, and then work out best way to use the space.

So I guess I am probably asking for paint advice from people who have painted over a combination of old epoxy & old untreated concrete floor.

This would be a short term measure, or perhaps a bit longer if combined with large floor rugs.

I have also seen some impressive paint work with stencils over concrete, but more suited to small area.

Thanks so much for all advise. I will flowers up on your tips and let you know how we go

Hi again Pottsy, will check out those tiles, sounds like a possible option

I know what it’s like renovating when your body can’t keep up with your mind. Another suggestion I would make and have just seen make a world of difference in a local shop - sheet vinyl, good old vinyl on a roll. This shop used it over concrete and it can cope with some variances in levels. They used a wood plank look which looks way better than I imagined it would. Not a DIY job but may be worth it. Easy to clean, covers all, done quickly. Prob not as cheap as diy tiles or paint but definitely do a comparison because paint and glue aren’t cheap.

PS a lot of flooring companies have calculators online so you can get an idea of costs.

A bit more research that I have done ( I'm in NZ , but very similar markets ) --

You will have problems getting any form of paint sticking to epoxy . In fact , I suspect you will have problems on any high traffic areas too -- whether it be 20 people walking 5 times each through a doorway , driving vehicles in , etc . Unless it is simply a place where 6 people work and a couple of people a day visit , I think you will regret painting .

Having said that , if you simply cleaned the best you can , and then paint , maybe $500 , it will delay having to spend bigger money .

Some other thoughts ( as well as the tiles and vinyl mentioned by myself and bigreader etc ) would be garage or marine type carpet -- I am assuming they are waterproof and will hide a lot and soak up most things .

As far as epoxy , here are 3 pics showing the prep through to the finished product . It will be several thousand dollars if professionals do it for your size area , but might work out better value in the long run -- oh , and it is 'rated' at 25 years of use ! Of course , dropping heavy items , sharp heavy items , power tools turned on , dragging 2 tonne items etc will affect it , as will the condition of the concrete , but on something like below , 25 years would be a reasonable expectation --