Raised floor in bathroom

Hi all,
could someone please explain to me why bathrooms always seem to have a raised floor even when there is sufficient drainage? I always seem to kick the edge & am trying to understand if we have to have one or it's better to have one or it is just easier for the builder to build it like that. Our csc hasn't been able to explain it to me!
Thanks
Lou

To NOT have a raised step into your bathroom the floor in the bathroom will need to be lower than the rooms it is connected to. The raised step is due to the tile screed and tiles which are much thicker than carpet, timber or normal tiled floors.
So if you are building a new house using concrete slab they would have to make the bathroom area drop down from all other floors by around 50mm to make the finish heights line up with connecting room. Can be done but i think it would be a lot more work & costs for the builder.
But if you have a timber stud floor style house than this can be achieved quite easily by cutting into the floor joists and lowering the floor but you may have to put extra studs in to compensate for the lowering of the floor as joists must be a certain width to support weight.

We don't have a "ledge/step" up or down.

I'd imagine it would be annoying.

For a concrete slab all the builder has to do is set the wet rooms down 40mm or so to allow for the extra sand/cement tile base and tiles plus falls to the floor grates as Splashers mentions however it is not very costly to do this at all.

Stewie

As Stewie said to rebate the wet area floors is not all that hard to achieve.
However it's not simply a case of making a section lower, it does require to be included in the slab design as there's a step down in the mesh that has to be taken into account.

Checked out the new display houses - couldn't believe they had hobs in showers and the ledge talked about above. So easy to do away with them yet they still do it !

100% correct, but it's all part of keeping build costs to a minimum but when you want to change something like that they can charge you for it.
Tis the project industry way.

AND ... they had about 24+ lights in kitchen / family area - where you might have 6 - 8.

Anytime we've done it in the past the engineer has been happy for us to excavate an extra 40mm in that area and simply bend the reo to suit. As long as we maintained the slab thickness and cover for the reo he was happy. I recall him saying though that any step down over 50mm needed the mesh cutting and cranked rods to be used which as you say would have added a bit more to the cost.

Stewie

I'm interested in this topic coming close to signing our final plans to go to the engineer.

I am unsure how to even understand if there is likely to be a set down other than ask the architect or his draftie. We are meeting them this afternoon so I am sure they will explain.

I'm still unsure reading this if it is easier or more difficult to achieve a flush finish on slab or bearers and joists. We are doing the house on bearers. One builder we met up with said bearers is more complicated than slab to achieve this. But we decided not to use him and I think he doesn't prefer to build in that way.

The draftie did ask us to carefully specify the floor finishes - timber, carpet, ceramic tiles to wet. I know this needs to be included in the schema but could this reason also be why she asked?

It's not hard to achieve it using a raised platform ie bearers and joists. Where the wet areas are you simply have those bearers set down 30 -40mm with the corresponding joists sitting on top. Or in those areas depending on the span you may get away with the bearers all the same level and just using smaller joists. As they have asked already, you need to specify what you are having for floor coverings in which rooms so they can pass that info onto the builder when they start building your house.
I should do a detailed section through a floor showing this as this question crops up on a regular basis.

Stewie

We drop down the up stairs wet areas in a lot of houses we build.
It is a fairly easy process but can be an expensive process also.
Its not just a case of making the wet area 60mm lower, it may be you need to increase the joist size of the remaining floor by 60mm.

We're having this done in our new build, bearers and joist flooring, builder very happy to do. As mentioned you just need to let your builder know. We are using a custom builder.

yes we are also having custom.

Does it need to be included at engineering stage?

It should be or at least the engineer should be aware of what you are trying to achieve and it wouldn't matter if you were having a slab or raised timber floor.

Stewie

Yes, engineer aware as is builder, draftsman and anyone remotely involved with the build, I want those floors haha

Thanks stewie and all.

The builder we were originally going with outright said no they would not consider it (pretty common project builder). We changed to another project builder and was easy to arrange. They are doing this in both bathrooms and the laundry and will charge us $750 all up so was happy with that. They determined the flooring height (slab) based on the measurements of the flooring that we are installing. Can't believe how cheap some builders are!