Using Old Slab for Shed Base was (Leveling compound...)

[wytco0]

I have to level a 3.6 x 2.4 meter base for shed, but the leveling is on top of a slightly sloping concrete slab.

The old slab used to be the base of a wooden bungalow. I have just measured the drop and its about 35mm over the 2.4 meters that I need to level.

I was thinking of leveling this with extra leveled concrete on top of the slope but I am concerned that this will be a lot of work as the slope is not very much and I think I will need to make the extra concrete at least 25mm thick or it will be to thin.

Another option is to use some sort of self leveling compound that can be poured and which will self level. Is there such a compound and can it be used outside and can it support the weight of a wooded shed?

I did post a question on this in gardening some weeks ago but didn't get any replies so hopefully someone on here can help me with what to use for leveling.

 

[big-all]

self leveling compound will not self level without you working it
it will act like treacle you need to work it and the final say 3mm will self level but not the whole amount

 

[^woody^]

Self levelling compound is not a wearing coat, and not suitable for external damp conditions

 

[wytco0]

Thanks for comments I did wonder about it and I haven't seen it used outside before plus is expensive.

Anyone got any suggestions for a solution?

Also if I do have to go for the Concrete solution, what is the minimum thickness that I can use that will have decent strength? by minimum thickness I mean for the extra concrete I will be laying on top of the existing Slab.

 

[wytco0]

I have just uploaded a photo showing the slab and with the ladders showing the approximate size of the bit that I need to level for the shed to sit on.

The existing slab slope with the right hand bit in the photo being slightly higher with a gentle slope down to the gully you can see on the left.

I am really stuck for ideas on how to do this so any help and suggestions gratefully received.

Untitled

• wytco0
• 1 Jul 2013
• 1

 

[ivixor]

Why does it have to be exactly level? It's a just a wooden garden shed, right?

If you really care you could level up one side of the shed with some slates or something like that.

 

[wytco0]

Why does it have to be exactly level? It's a just a wooden garden shed, right?

If you really care you could level up one side of the shed with some slates or something like that.

Its a heavy duty shed and I will be keeping ride on etc in it, I want it to be level and supported across the whole width and I don't want it twisting and the doors jamming etc.

 

[wytco0]

I have just updated the first post as I have now measure the drop accurately and over 2.4 meters is 35mm.

 

[wytco0]

Um seems this is a problem, I think I need to use a minimum of about 25mm of concrete if I use 10mm gravel, that means the additional slab will vary between 25 and 60mm. Seem a bit of a waste as its all on top of a decent slab anyway.

Trouble is I can't think of another solution....

Maybe I can just mortar a few bricks along the low side and back-fill them with 10mm gravel and level the gravel.

 

[Deluks]

I agree with previous bloke, it's not a lot of difference, level it up with bit of roof tile, paving slab, etc.

 

[mfarrow]

I know of a perfectly level concrete slab with a shed on it. The shed is slowly getting shorter owing to the sodden, rotten floor and base of the walls.

Raise it up on slabs, then use whatever shims you find appropriate to level it out.

 

[maltaron]

Screed it to level with 6mm to dust granolithic aggregate mixed 5 to 1 with cement. You can lay that to 12mm thick no problem. Put timber formwork around the edges to your required levels and tamp to that. If you are any good with a flooring trowel it will polish to a smooth finish after around 4 hours.

 

[pred]

Has shed got timber joist running across underneath the base?

Are they 2.4m or 3.6m

 

[wytco0]

Has shed got timber joist running across underneath the base?

Are they 2.4m or 3.6m

Yes it does have joists under the base but I am not sure which way they do but I can check in the morning.

Interested in why you ask?

 

[pred]

Probably 2.4m, so if you get say 4 lengths of 3.6m 4X4 and about 16 slabs or concrete blocks set out the blocks in each corner, flat, use sand/cement and the 4X4 to level them through, start at the highest point with a small bed, when you have the 4 corners sorted then put a block circa every 1.2m so you end up with 4 rows, place your 4X4s on the blocks and your shed on the 4x4s, as it's off the ground it wont rot so quick.