Thoughts on this

[Stef]

This is interesting as this was the way I was going to do my bathroom floor to keep the height to a minimum.
I was going to fix 4x2 or 5x2 along side the original joists, think they are 6x2, to strengthen the full floor.
Fix Marmox/Wedi on top, Ditra then heat mat, SLC, then tile.
Do you think this would be a viable option? 8/9m2 in total.

 

[charlie1]

This is interesting as this was the way I was going to do my bathroom floor to keep the height to a minimum.
I was going to fix 4x2 or 5x2 along side the original joists, think they are 6x2, to strengthen the full floor.
Fix Marmox/Wedi on top, Ditra then heat mat, SLC, then tile.
Do you think this would be a viable option? 8/9m2 in total.

no plywood? What will be your primary subfloor robby?

 

[Alan M]

we did a job a while back like this.
there was 9x 2 floor joists. we had to lower the floor by 2" for ply, tiles etc.
the span wasnt that big
we glued ,screwed and bolted 7 x 2" s to the side of the 9x 2"s then put noggings in every 3 feet and 2 layers of 18mm wbp overlapped , glued and screwed to everything
we got an engieer to give the ok. he said it was more than strong enough for anything they could put ontop of it.

i would want to see the builders work as they go along . and get a copy of the engieers report to cover yourself

 

[Stef]

no plywood? What will be your primary subfloor robby?

I would fit the ply between the joists.
The top if the ply would be flush with the top of the joists.

 

[Ajax123]

too much information !

Ooops!

 

[charlie1]

I would fit the ply between the joists.
The top if the ply would be flush with the top of the joists.

Imo, the plywood would loose a significant amount of its strength and would flex considerably more. Imagine the cross section of plywood on suspended timber floor, now focus on the section directly above the joist, when you apply pressure here, the floor us solid, now imagine the same section but pressure applied the span next to the joist, if you could focus right in then you would see the top of this section of ply would be in 'tension' thus giving the section across the span more strength and less flex.

maybe it could be done Robson with plenty of noggins.