Finished height of concrete garage floor above ground level

[megger]

Hello, I am about to put down a 20ftx12ft concrete slab for a timber garage. It is detached from other buildings. The lawn and earth will have to be cut into to get a depth of 200mm for dolomite and concrete slab. I was intending to have the finished height 40mm above the lawn to allow for standing water (should this ever occur) as I don't want rain water flooding in.
Is there a regulation that recommends it has to be higher.

Thanks in advance.
megger.

 

[Tigercubrider]

My semi's garage has the garage less than 12 mm higher than the drive
I believe the drive to be original to the house, which is 65 or so years old.

Obviously standards may change. My garage does get wel at the front, due to rain being driven by the wind.
If going for 40mm I would make a gentle slope at the car entry

 

[noseall]

Is there a regulation that recommends it has to be higher.

No. Stand alone garage floor height should be set for practical reasons whilst bearing in mind any building finished height restrictions. If for example the garage was situated at the bottom of a sloping drive, it would make sense to accommodate a rising apron up to the garage door i.e. lowest point of the drive +75mm or so.

When I set the FFL for this double fella I had to juggle ease of access v's flood risk v's finished ridge height (planning).

Garage2

• noseall
• 15 Mar 2019

 

[Scarlet Pimpernel]

I used a concrete ramp, and a linear drain along the bottom of the ramp. The linear drain just diverts water around the sides of the garage. It's not connected to any drain system.

 

[Diver Fred]

Dont think there is any restrictions on Gargae floor 'level above ground level but I do strongly recommend that you do have a 'Fall' on the finished floor draining towards the entrance. Over 20 feet you only need 1 or 2 inches at most with a smothed floor. A little more if the floor is left with the finish from the tamping (i.e. rippled) particularly if that is at right angles to th etamping marks.
That allow the water collected on a car dueing a rain storm to drain away from the car and garage walls.