# Forum Home Renovation Sub Flooring  How make bathroom subfloor lower than bedroom, and sloped?

## jaffakatie

Hello, Him and I are new renovators (he's doing the work, I just come up with the difficult ideas). 
I'm after advice on adjusting subfloor to account for different floor thicknesses and bathroom slopes - or do it all above joists? 
I want the bathroom to be no higher than bedroom - would like them level or bathroom to start say 5 or 10 mm below. (In existing house  bathroom floor has been built onto rest of floor so sits 10 mm higher  and opens opportunity for flooding to come into rest of house). 
(Despite  slope and drain a friend minding my parents house left bath running,  fell asleep waiting to fill, mat on floor over drain blocked it and lots  water came out into bedroom - but that's what insurance is for I guess)   Bathroom is in corner of new extension with hardwood bearers in place (no joists yet).Bedroom hardwood t&g timber floors 19 mm to sit straight on joists.Bathroom, scyon 19 mm plus adhesive plus tiles. Plus a fall in floor.Bathroom 2.8 wide as you go in and 2.9 m away.Bedroom door into bathroom is mid way along bathroom wall. Toilet (left) and shower (right) on opposite (back) wall.Shower about 1300 x 1300 (with cut off corner as door nearest toilet) and a 600 mm long floor grate to go under the right hand shower wall extending from right hand bathroom wall.As such, grate is close to being in middle of room across ways, but extends out 600 toward middle of room from the right wall.Therefore slope from left needs to travel about 2200 to reach grate and 1300 in shower or 1600 from front wall.This needs at least a 22 mm drop from left to right just to the edge of grate to get a 1:100 drop. 
Plan is to put 125 mm high joists in bedroom and robe (both adjoin the bathroom) and then 75 high mm joists on the bathroom part, so they will start 50 mm lower or will be packed up to get bathroom more level with bedroom at doorway. 
What is the best option:
1. Build scyon floor level and use the tile adhesive to make the slope, and tile straight onto the adhesive of different thickness. Does ceramic tile adhesive have the capability to be 25 mm thicker at one end??
2. Build scyon floor level and put a concrete (or other - what???) screed over to make slopes, then adhesive and tile over
3. Build scyon floor with a one way slope (left down to right) using different joist height (or packing), then make other slope adjustments from the side with tile adhesive.
4. Build scyon floor with a one way slope (left down to right) using different joist height  (or packing), then make other slope adjustments from the side with screed (then adhesive and tiles).
5. Build scyon floor with 3 slopes - divide room into 2 halves -1st half closest as you walk in, and back half under toilet and shower. Make both slope a bit from left to right , but also make each half slope to each other (to long grate which would be positioned where the 2 halves meet). Make all this with different joist height/packing. Then tile over.  (sounds very complicated and unlikely that real builders go to this trouble). 
(All assume waterproof seal at joins/edges etc.) 
I'm hoping Option 2 is suitable - but please say so if no best option.
If it is, can you just concrete over the scyon? Or is there some special stuff to use for such an application? 
Also this option would make the wall framing easiest. We'd simply frame the exterior bathroom walls separate to adjoining exterior walls, sitting them straight on scyon, just starting a bit lower than bedroom frame, which needs to go on a base plate on the joists and the hardwood floor gets put in later. 
thank you

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## cherub65

Screed floor to waste with sand and cement mix 1:4, then glue tiles to screed.

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## Master Splinter

If you really want a floor that doesn't have the usual little step-up aluminium lip to a wet area, your best bet is to speak with the company supplying the floor joists and find out what they recommend - often the floors are designed as systems, so adding a spacer to raise the level of the rest of the floor may require the use of extra glue, longer nails and so on to maintain the correct deflection under load.

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## jaffakatie

Thanks Master Splinter, we are doing this ourselves and we already have the joists. They will be 75 mm high in bathroom and so already give a 50 mm drop compared to 125 mm ones in bedroom, though the bathroom floor will be a bit thicker scyon 19 mm, tile adhesive a few mm and tiles probably 8 mm, whereas bedroom is just wood 19 mm.
Cherub65, the level floor and screed to waste as you say seems the most logical choice. we are currently using a similar mortar for a rock feature wall with sharp/washed/plasterers sand (it also has some lime in it and bondcrete)

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