Precast Flooring

pete6296

Hi,
I am putting in hollowcore flooring and company supplying it supply 6 inch for domestic dwellings. However, my engineer wants 8 inch but company say 6 inch is standard and don't understand. Has anyone else seen this.
Thanks,
Peter

smashey

If your engineer has specified 8", tell the supplier that's what is required as the Engineer will have to sign off on it.

muffler

What smashey said.

You could of course ask your engineer for his design calculations and take these to the company concerned or vice versa.

Tails142

The depth of the slab all depends on the span. If its a large span that's why the engineer is specifying 8"

Go with whatever the engineer says or else pass on the info to him/get him to check out the slab manafacturers specs and redo the calculations

muffler

Tails142 wrote: »

The depth of the slab all depends on the span. If its a large span that's why the engineer is specifying 8"

Go with whatever the engineer says or else pass on the info to him/get him to check out the slab manafacturers specs and redo the calculations

The span is one factor only. The other main factor is the loading (self and super-imposed). A general rule of thumb for medium spans up to approx 4500mm is that a 150mm slab will suffice for carrying the upper walls but a trussed roof is needed.

If the upper walls are to be used for supporting the roof then a 200mm slab will be necessary. Again its all down to the design criteria.

ircoha

In addition to the loading requirements which are paramount, another consideration here is the use of structural versus non-structural screeds as a finish.

The 8" option may negate the need for a structural screed, hence one less item for the engineer to worry about.

250882

I think its a bit daft to assume that because the slab is 200mm instead of 150mm that a structural screed isnt needed, it depends on the span, the loading the loor buildup, you cant say that its because the engineer is being lazy. I know theres cost implications as well as issues with floor depths so ask your engineer to contact the pre-cast manufacturer and get them to certify a 150mm floor in that location.

pete6296

I have contacted engineer in the meantime, he is in discussion with manufacturer and i will know in the next few days. I will let board know the outcom.
Thanks

pete6296

Hi,
Hollowcore is 8 inches, block is 9 inches. How would the blocklayer finish with a 1 inch gap. Fill up 1 inch with mortar? Usual is a 6 inch hollowcore or 9 inch. Am i missing something here?
Thanks,
Pete

muffler

pete6296 wrote: »

Hi,
Hollowcore is 8 inches, block is 9 inches. How would the blocklayer finish with a 1 inch gap. Fill up 1 inch with mortar? Usual is a 6 inch hollowcore or 9 inch. Am i missing something here?
Thanks,
Pete

is this a dormer type house or 2 storey and i assume you are talking about the spare inch between the slab edge and the cavity.

pete6296

Its a 2 storey, i am talking about spare inch between slab edge and the cavity, thats true. What do we do?