minimum thickness of concrete

[JohnDeere8530]

I have an old building with an old concrete floor in it in poor/average condition. It gets damp, so I want to lay DPM on it and re-concrete. Would I get away with 50mm thickness do you think, bearing in mind that the access is by a pedestrian door only, so will never take any vehicular traffic? It also never has any sun on it so wont be subject to thermal movement either.

Thanks in advance

 

[RWG Contracts]

I'd say it's to thin, but someone else will come along and say it's fine

 

[RWG Contracts]

100mm is the thinnest I'd ever consider going

 

[Lufin]

Wouldn't you be better screeding it instead?

 

[bobk]

50mm in your situation could be ok

 

[Lincs Lass]

Tarmac slurry

 

[RWG Contracts]

50mm in your situation could be ok

Could be

 

[bobk]

Could be

May have meant should

 

[JohnDeere8530]

might go 75mm then. I have around 75bags of cement about to go off given to me, so needs using up.. Just a faff laying it thats all

Someone suggest sharp sand, is the right stuff to use?

floor is 7.9 x 7.9m so at 75mm, I'll need 4.6m3 of concrete or at 50mm I'll need 3.12m3 of concrete,

How much cement in weight/volume ?

6bags (20kg) to a m3 ??

 

[Lufin]

Sharp sand and cement is a screed

 

[Lufin]

http://www.concretecentre.com/Building-Elements/Floors/Floor-Screeds.aspx

 

[Dry Rot]

How thick are paving slabs? They seem to do the job OK.

 

[Pond digger]

You need a sand & cement screed over bitumen emulsion damp proof coat.

 

[JohnDeere8530]

dpm aka double thickness silage sheet do ? ;-)

 

[Frodo2]

What is causing it to get damp and deteriorate? If the old concrete has broken down due to not being sufficient spec why repeat the mistake?

 

[BobGreen]

might go 75mm then. I have around 75bags of cement about to go off given to me, so needs using up.. Just a faff laying it thats all

Someone suggest sharp sand, is the right stuff to use?

floor is 7.9 x 7.9m so at 75mm, I'll need 4.6m3 of concrete or at 50mm I'll need 3.12m3 of concrete,

How much cement in weight/volume ?

6bags (20kg) to a m3 ??

250 to 300 kg cement /m3

 

[Forever Fendt]

If you can not afford or justify to put concrete down min 6" don't do it

 

[RWG Contracts]

If you can not afford or justify to put concrete down min 6" don't do it

Do it right, do it once

 

[SilliamWhale]

If you can not afford or justify to put concrete down min 6" don't do it

For goodness sake, for pedestrian use that is over the top

 

[JPM]

We do our cubicle beds at 3" deep concrete and never had any problems. 5" on scrape passageways and 6" on feed passageways