Concrete slab - Need advice

RobinBanks

Hello All,

I am thinking of putting in a new concrete slab in front of the slatted house. The idea is to raise the floor where the cows put there heads out to eat by 4" and slope this down to the existing concrete slab. We have a problem in that with a single bay shed any rain that blows into the opening of the shed will lie on the ground where the silage is and then I find we end up dumping allot of silage.

Could I put a new slab on top of an existing one? Will I need to break the existing concrete and will it bond/join to the existing floor at the thinnest point i.e. at the bottom of the slope. The idea is to drain off as much water as possible and also to have the outside slab higher than where the cows are standing so no muck can be pushed out under the gates onto the silage. This happens allot in the middle pin as there is no wall, only one long gate. Would it be a waste of money and would it be too expensive to justify doing? It will mean I will have to re-hang the gates but that shouldn’t be a big deal. By the way, the shed is a 3 bay and the width of the slab would be approx 7ft.

See attached sketch which shows what I am thinking of.

locky76

Personally Robin i don't see the benefit in doing this, you're going to find it vary difficult to bond the old and new concrete and it's going to flake away out at the edge, just my tuppence worth:rolleyes:

RobinBanks wrote: »

Hello All,

I am thinking of putting in a new concrete slab in front of the slatted house. The idea is to raise the floor where the cows put there heads out to eat by 4" and slope this down to the existing concrete slab. We have a problem in that with a single bay shed any rain that blows into the opening of the shed will lie on the ground where the silage is and then I find we end up dumping allot of silage.

Could I put a new slab on top of an existing one? Will I need to break the existing concrete and will it bond/join to the existing floor at the thinnest point i.e. at the bottom of the slope. The idea is to drain off as much water as possible and also to have the outside slab higher than where the cows are standing so no muck can be pushed out under the gates onto the silage. This happens allot in the middle pin as there is no wall, only one long gate. Would it be a waste of money and would it be too expensive to justify doing? It will mean I will have to re-hang the gates but that shouldn’t be a big deal. By the way, the shed is a 3 bay and the width of the slab would be approx 7ft.

See attached sketch which shows what I am thinking of.

JohnBoy

As locky says you'll have issues making it work.

at a minimum you'd want to drill a series of holes in the original slab and drive in short lengths of rebar, do them at angles for maximum effect.

Then out at the front you need to cut a channel, or extend the sloped bit out beyond the existing slab, and maybe break the corner off the existing slab to give a bit of thickness at the edge. it's possible, but a share of work, helped out on a very similar job for a friend years ago, but his sloped section was only extending around four foot into a 12 foot passageway. we cut the line along the edge of the slope with a consaw and then kango'd out the original slab. the work had the desired effect and solved the same problem you're having.

RobinBanks

locky76 wrote: »

Personally Robin i don't see the benefit in doing this, you're going to find it vary difficult to bond the old and new concrete and it's going to flake away out at the edge, just my tuppence worth:rolleyes:

Hello Locky,

After I wrote this message I thought about a friend of mine who is an engineer with coffeys. He sent me a plan on how to do it and how to avoid flaking and create a bond between the old and new concrete. I will work out the costings and if relatively cheap I will consider doing it. I am not adding any real value though so its hard to justify carrying out the work alright.

vincenzolorenzo

Surely for all the concrete you'd need to make a small wedge like that it wouldn't be very expensive. Hire out kango/consaw/whatever you need for a day or two and then pour the concrete? Seems like a reasonably straightforward job to me? If you're losing much silage from it sitting in water then you wouldn't be long getting your money back

RobinBanks

JohnBoy wrote: »

As locky says you'll have issues making it work.

at a minimum you'd want to drill a series of holes in the original slab and drive in short lengths of rebar, do them at angles for maximum effect.

Then out at the front you need to cut a channel, or extend the sloped bit out beyond the existing slab, and maybe break the corner off the existing slab to give a bit of thickness at the edge. it's possible, but a share of work, helped out on a very similar job for a friend years ago, but his sloped section was only extending around four foot into a 12 foot passageway. we cut the line along the edge of the slope with a consaw and then kango'd out the original slab. the work had the desired effect and solved the same problem you're having.

That was the same advice my friend gave me! He also mentioned that i should use a scabble to roughen up the old surface

Dupont

lets say you choose to rip it up.2 men for a day 160.air compressor,kango,consaw for one day 200. 2men for a day getting ground ready and then concrete 160. 50 for stone if needed. 4 metres of concrete if going 4" deep(i would recommend 6") 30n20 at 64 a metre. bull float or maybe magic screed 50. shouldnt cost more than 900-950.providing other concrete is not 9" deep layed on top of mesh:eek:

blue5000

I'd suggest put mesh in the new stuff too. Also wet the old stuff just before you lay the new concrete, it will help it to bond.