Bricks, Masonry, Asphalt and Concrete - Help - garage base cracked down the middle

Hi All,
Need some advice please , We had a garage base put down about 18 months ago this was put down behind our house at the end of our garden big enough for a double garage and a gym, 3 months ago we had all the brick work done and then noticed a crack across the base of the floor, when inspected we have been told the base might be 6 inches thick but the hardcore base was either to thin or non existant, i have spoken to the builder who did the base who said he`s done nothing wrong yet the council who deal with planning permission have said to stop building. what should i do ????? :confused:

Pull the whole thing down and dig up base, and take builder to court ??? even though hell get away with it.
reduce the size of the garage ???
get the base pinned ??? how much will that cost ???
Help.

By "garage base", I assume you are talking about a structural slab. It sounds like you do not know the reason for the crack, so you should first hire an engineer to determine the cause. Since the "council" got involved (more likely a city employee), you will need to get a profesional opinion instrad of guessing about the severity and cause.

If you have not had any equipment on the slab, it probably is not a structural crack. If the crack is in the center it may just be a shrickage crack. It will take having someone examine the slab to determine the likely cause. The type of structure you described puts a minimal load on the slab.

"Pinning" and tearing out the base should not be considered until you know the cause and severity. It could be the slab and base is fine, but you subsoil is not satisfactory to place a building on. - Only a professional investigation will tell what the real situation is.

I assume you had a permit, so you should have had the benefit of some kind of inspection. Your agreement with the contractor should also provide information on the specifications (compaction, control joints) and materials (strength, reinforcement) for the slab.

Good luck!!

Dick

How many crack control joints were tooled or cut into the slab? It sounds like a fairly large area, so if you say there are no joints, then that is the problem. Concrete cracks, period. The reason for crack control joints is to make the slab crack there instead of randomly. If you cut no joints, then you get random cracks, no matter how thick or thin the slab is. On a slab of that size, there should be joints cut roughly every 10 feet each way. The joints should be a minimum of 1/4 as deep as the slab is thick (1" deep for a 4" thick slab, 1.5" for a 6" slab, etc.)
Cracks happen for a variety of reasons, but most cracks in new slabs happen due to shrinkage of the concrete, and usually within a few days of the pour. The wetter the concrete is poured, the more shrinkage you will get, and therefore more cracks. On older slabs, cracks are usually caused by voids under the slab due to ground settlement, excessive weight on the slab, or frost heave.

Pecos

Thanks for the replys at the moment - The Contractor who did the base is not being cooperative at all,i have a dispute now between contractor and the council one saying everything is ok and the other saying building must stop, i re-call the base being dug out some hard core packed down, then damp sheet put down and the concrete poured in from the cement wagon, a apologise for my basic description but i know nothing about building.as it dried out a few very small cracks appeared and was told not to worry it happens normally when done in the summer heat.since the brick work has been done and is winter here in britain the crack appears to be wider.seems ive spent alot of money for nothing, no point carrying on if it could be unsafe , i was told carry on but the garage would need to be smaller or the base needs pinning from the council who control building regulations.what does pinning entail ????