Levelling a cobbled floor

[jagxkr]

Hi everyone - this is my first post (so go easy), and already I'm in awe at some of the projects I've browsed! Nice stuff. I'm fairly handy around wood and metal, not quite at the precision of some of the stuff I've seen here. I made a guitar once, that turned out ok. But I digress!

My garage is a victorian coach house, a bit wider than a standard single garage but nowhere near a double. Space is tight, especially if there's a car in there, so I'm taking to putting most things on wheeled stands if I can. It has a cobbled floor that was optimised for shifting horse excrement out of said building, so not level and also bumpy due to the cobbles. I am toying with the idea of levelling it, as I do work on cars in there, and also moving wheeled things around on the cobbles is not a lot of fun.

It's a nice building and I want to preserve the floor, so pouring anything is out of the question.

I currently have an excess of roofing battens and am thinking about laying them on their flattest side, with a 22mm chipboard on top, and I a noggin-type arrangement between them (apologies, if the continuous batten lengths were joists, perpendicular short lengths between them would be..?),
I also have an excess of roofing membrane which could prove handy under the battens.
Anyway, given that I plan to work on a 2 tonne car in there:
a) am I completely nuts and b) would 12 inch spacing between battens/noggins sound about right? Could I get away with simply fixing the chipboard to battens and not anchoring the battens to the floor?

I am mostly concerned about the load of ~500kgs on each axle stand if a car was up on stands in there. I have had a quick look at a spec for caberboard and can see it is very stiff (high Youngs' modulus) but have no idea what modulus of rupture is and how to figure out if it will take the load I describe..perhaps 18mm ply would be a better (but more expensive) option.

I could go for a herringbone type arrangement between the main "joists" I suppose..

There are other levelling threads in here (that's how I found the forum) but I haven't seen anything along these lines. So very much appreciate your thoughts.. thanks in advance!

 

[RobinBHM]

I think you could lay some dpm down first on the cobbles.

Then lay your battens with something underneath to level them up -Im not sure roofing battens will do, more like 4 x 2 laid flat at 300mm centres. I would suggest temporary screwing a 4 x 2 to your floor battens to connect a load together and then level them up to each other, remove and then screw down your deck

I dont know what you could use to level them up, some sort of mortar?

I would use 18mm plywood for the deck or 18mm OSB. Im not sure chipboard will cope with a point load like an axle stand. I suppose you could sit any axle stands with a square of ply underneath?

 

[sunnybob]

4 inches of concrete, some self levelling compound, and either tiles, vinyl, or concrete paint.

Next?

 

[dynax]

clear resin, not cheap, but will preserve the cobbles, and give a strong clean and level surface,

 

[nev]

Would dry sand spread to a few mil over the highest cobbles to make level and then some sheets of ply doubled up offset and screwed/ glued to give a floating 1 piece floor work?

 

[AJB Temple]

If you want to be able to remove the flooring, but wheel things over it easily and also achieve some significant insulation, I would use interlocking rubber drain through stable tiles for equestrian use. You can buy these at various thicknesses up to about 50mm though 30mm should be enough for you. They are usually a metre square. Can be cut with a jig saw. This flooring is quick to lay, warm and gives an exceedingly durable surface as they are intended for horses shod with steel shoes. Very easy to remove. You could easily sell them on as well I expect.

 

[sunnybob]

Oh boy, perforated rubber mats would be heaven to sawdust. youd never get it clean.

 

[jagxkr]

4 inches of concrete, some self levelling compound, and either tiles, vinyl, or concrete paint.

Next?

It's a nice building and I want to preserve the floor, so pouring anything is out of the question

 

[jagxkr]

I think you could lay some dpm down first on the cobbles.

Then lay your battens with something underneath to level them up -Im not sure roofing battens will do, more like 4 x 2 laid flat at 300mm centres. I would suggest temporary screwing a 4 x 2 to your floor battens to connect a load together and then level them up to each other, remove and then screw down your deck

I dont know what you could use to level them up, some sort of mortar?

I would use 18mm plywood for the deck or 18mm OSB. Im not sure chipboard will cope with a point load like an axle stand. I suppose you could sit any axle stands with a square of ply underneath?

This sounds sensible. Why take the risk with chipboard. I may as well bite the bullet and use ply, if nothing else for piece of mind. Thanks!

 

[jagxkr]

If you want to be able to remove the flooring, but wheel things over it easily and also achieve some significant insulation, I would use interlocking rubber drain through stable tiles for equestrian use. You can buy these at various thicknesses up to about 50mm though 30mm should be enough for you. They are usually a metre square. Can be cut with a jig saw. This flooring is quick to lay, warm and gives an exceedingly durable surface as they are intended for horses shod with steel shoes. Very easy to remove. You could easily sell them on as well I expect.

Hmmm this is actually pretty interesting. I was imagining the perforated matts ( definite no as I'd be losing stuff all the time in the holes) but there are a variety of surface finishes. Would be interesting to know how stiff they are. Thanks for he food for thought!

 

[jagxkr]

Would dry sand spread to a few mil over the highest cobbles to make level and then some sheets of ply doubled up offset and screwed/ glued to give a floating 1 piece floor work?

Not a bad idea at all. I think i'd probably lean toward mortar underneath the battens (but on top of a membrane) to reduce the risk of water ingress washing away my levelling. That is not too likely but I think I'd be worrying about it. Thanks though!

 

[AJB Temple]

The thicker rubber mats are very stiff and heavy. I put them in four big stables at my former house.

 

[Terry - Somerset]

Don't know if he floor is level or slopes towards/away from the door but bear in mind if door opens inwards it would need to be trimmed, and any extra floor level over (say) 30mm may need some for of ramp in the doorway. So a 4 x 2 frame under chipboard or ply will create a very noticeable step.