Building walls before floor slab

[SALL2009]

Is it possible to pour concrete floor slab after getting an extension to roof level. I am getting an extension to the right hand side of a current single story wing. I am looking at the possibilities of replacing the current external wall at the right hand side with a stud wall. (It will be an internal wall after the extension)

Would it be better to pour the slab after the wall has been knocked, so the DPM from the old floor can be joined with the DPM for the new floor?

I don’t want to knock the wall before the new extension is build, because the house will be in use throughout the work and I don’t want to cause major disruption for that long.

Or can anyone suggest another work around to what I want to achieve.

 

[Ricke21]

I can't see a problem for when you do the floor. But if it's done before you join the two floors (or take out wall) then just make sure you leave enough dpm to lap over to existing.

 

[r896neo]

It's not a problem at all apart from access. Chuting through a window into barrows can be a little messy just make sure to clean everything on the outside quickly as there is some sort of extra 'slime' other than cement in readymix that leaves awful stains.

As far as the dpm i personally wouldn't worry about trying to lap under eachother as long as both slabs have enough dpm turned up the side and they are tight together you'll have no problem.

 

[RedHerring2]

Would it be better to pour the slab after the wall has been knocked, so the DPM from the old floor can be joined with the DPM for the new floor?

I don’t want to knock the wall before the new extension is build, because the house will be in use throughout the work and I don’t want to cause major disruption for that long.

That's exactly the same situation as I'm in.
I've laid the bathroom and conservatory floor slabs but the kitchen slab will be laid after I've removed the old wall.
The existing slab is dpm'd with something like Synthapruf between the concrete and the screed and there is no insulation.
The new slab will be insulated and dpm under the concrete, so I'll 'lap' the joints vertically as best as possible with judicious use of membrane and Synthapruf.

 

[SALL2009]

Thanks guys. Just wanted to make sure my plan was reasonable.

 

[simonjay]

It's not a problem at all apart from access. Chuting through a window into barrows can be a little messy just make sure to clean everything on the outside quickly as there is some sort of extra 'slime' other than cement in readymix that leaves awful stains.

I think its usually diesel that is used as a lubricant, especially when its being pumped. There's a handy source of it on the truck !
Simon.

 

[noseall]

I don't see why the floor cannot be done conventionally i.e. when access is at its easiest prior to building any walls. The polythene can be tacked up the wall then folded down later on.

The concrete could be kept 75mm lower than FFL and a screed added later after the knock-out to bring all floors level.

...or am i missing summat?