Garage Refurb

[ZorgTheDestroyer]

Hi all,

In the process of updating our garage. It's a stand alone building, brick on the inside, stone on the outside. The internal floorspace is 3.4m * 4.7m. It's just be used for storing bits and pieces and we decided that we'd like to update it, maybe use it as a gym.

The floor was a bit of a mess, the cement was cracked everywhere and wasn't level:

Plus the electricity comes into the property here as well (that black tubing in the middle of the wall).

I started removing the cement and it came up really easily. I didn't even need my breaker, it was only an inch thick and seemed to have been laid on top of cinder blocks from a slag heap.

Anyways, so I removed the cement and the cinder. So the garage floor now looks like this:

So the first point is about the leccy. It seems like underneath the cement where the electrical supply comes into the garage is a big stone and some rusted iron bolts holding something in place (although one of them broke and I left it on top of the slab). I was worried about doing anything near here so I've just left it.

What I want to do, is lay a new concrete slab. So in my mind, this needs to be 4 inches thick. There's no cars coming in here, so I 'think' that this would be enough?

What I think I need to do next is: get a whacka/vibrating plate to flatten everything down, probably put an inch or 2 of sharp sand, then a plastic sheet and get 1.6 cubic metres of ready-mix poured in.

However, do I need any shuttering/form-work? since everything will be below the level of the garage door by a couple of cms. Also what to do about the leccy point? What's the best approach to deal with that?

That bit will also stand proud of the cement, so I think I'd need to look at taking the top 3 cms off it somehow.

If I were to get that down to the same sort of level as the cement slab, I think I'd still end up with bridging between that bit and everything else. So, unless anyone can point me in a different direction, as I'm writing this, I think I'm going to have to see if I can remove that stone (or at least the top layer of concrete on it).

All advice gratefully received.

Thanks,
Tony

 

[DAZB]

I would certainly be putting insulation in the slab as it will make a big difference to the room but you would need to dig lower to accomodate it ? Also have you allowed for the finished floor level on top of the concrete which could be wooden flooring, vinyl, rubber gym mats etc... as you could make that point flush with the slab around the electric point and then there is no need to reduce it ?

 

[jj4091]

I would also use rebar mesh to reinforce it and stop cracking. https://www.google.com/search?q=reb...EGNEDGMcBGAqYAwCSBwMwLjWgB_JA&sclient=gws-wiz Also is that an air brick to the right of the electric cable. If it is and it goes through under a suspended floor then I would clear that out while you are there.

 

[ZorgTheDestroyer]

That was interesting about the insulation slabs,just saw this youtube where this person was putting down kingspan on top of concrete and then putting 22mm plywood on top of that.
https://www.youtube.com/watch?v=I7GD0MB8SzY


I think I've got about 140mm to play with (depends on the what the whacka-plate can do as the floor is all this cinder material - maybe more).

I'm thinking that could get 100mm of cement, then put DPM sheet then 20mm kingspan board, then 18mm plywood.

If I put a rebar mesh in there, could I go less than 100mm thick for the concrete I wonder?

 

[Tigercubrider]

Is fibre reinforcement suitable for a floor?

 

[jj4091]

You need the DPM on top of the sub-base not the concrete. The rebar would not decrease the thickness required. I would not recommend fibre reinforced concrete either as that cracks over time. There is no need for Kingspan for a floating floor just use 50mm polystyrene underneath 18mm moisture resistant T & G chipboard flooring.

 

[ZorgTheDestroyer]

Another question around this, do I need to put in shuttering?
I'm going to box off the area with the electric coming in with wood and expanding foam. For the rest of the area I'm going to put DPM down, which will go up the wall 20cm (I'm only doing 10cm depth). Because all this will be below the level of the door/garage threshold I can't see the point of creating a wooden form.

For laying concrete from a ready-mix truck, can anyone point me in the direction of any tips about laying concrete generally and from a truck?

I can see people doing an amazing job floating the cement on youtube but I don't think I need to worry about this since I'll be covering it with insulation, chipboard and then gym-mats.