Would this be a job for Dita to be used?

[kickkick]

Hi Guys.

I have a small bathroom floor about 5 square metre. The problem is this.
The house is a chalet bungalow and the bathroom up in the roof space along with the bedrooms etc.

The chip board flooring is fixed to the roof trusts. Then the floor has been over boarded with the correct size plywood with expansion gaps and screwed down in the correct fashion. Now because the roof trusts are prone to normal building movment I have a concern that the plywood is also screwed to the chipboard floor then there final finsh would result in cracked tiles etc etc. I was wondering if this sort of problem would be solved but using Ditra Matting over the plywood and thrust avoid the problems that the roof trusts can bring.

Many Thanks
Karl.

[Dave]

Is the floor deflection free...if it is then Ditra will be useful against lateral stress cracks...transfering to the tiles..

[LM Ceramics]

agree with dave on this one

[doug boardley]

but if the roof trusses move the floor up and down it would, imo, be a job for 6mm hardiebacker

[Dave]

If it moves up and down doug....then no tiling it, till it's sorted...

[Gazebo]

If it moves up and down doug....then no tiling it, till it's sorted...

not even rubber tiles.?

[doug boardley]

If it moves up and down doug....then no tiling it, till it's sorted...

senior moment

[kickkick]

Nah the roof turst done move up and down thank god. Just normal side to side movement of a few mm.

Thank you for your great input. I must really post hear more often and get involved as I have been reading the forum for a few years with no input.

[Dave]

All input is great.....a lot of good lads/lasses on here

[mikethetile]

have i understood you right

the floor is laid direct on the ceiling joist of the roof truss.............surely not

"joists dont deflect up and down but deflect sideways by a couple of mm"

im hoping youve got this wrong mate and the floor isnt laid on the cross ties of trada trusses

your floor joists should be around about 200mm x 50mm at either 400 or 600 centres depending on span

if they are 100 -150 they are ceiling joists only and not intended to take a floor

if you fit out a fully tiled and fitted bathroom in the loft it will only be a matter of time before you have a new downstairs bathroom

please check the dimensions of the joists before going any further, many chalet bungalows were intended to have the loft floored and used for occasional use and storage of light items they were never intended to be used as living space

im sorry to be like this with you mate but i dont want to see you coming unstuck in the future

hoping you have got floor joists

mike

[kickkick]

have i understood you right

the floor is laid direct on the ceiling joist of the roof truss.............surely not

"joists dont deflect up and down but deflect sideways by a couple of mm"

im hoping youve got this wrong mate and the floor isnt laid on the cross ties of trada trusses

your floor joists should be around about 200mm x 50mm at either 400 or 600 centres depending on span

if they are 100 -150 they are ceiling joists only and not intended to take a floor

if you fit out a fully tiled and fitted bathroom in the loft it will only be a matter of time before you have a new downstairs bathroom

please check the dimensions of the joists before going any further, many chalet bungalows were intended to have the loft floored and used for occasional use and storage of light items they were never intended to be used as living space

im sorry to be like this with you mate but i dont want to see you coming unstuck in the future

hoping you have got floor joists

mike

Yes you are correct. I did forget to mention that there is indeed joist spanning across the building between the roof trusts, and the upstairs floor is indeed fixed to the joists and not the roof trusts.

Do you still think there would be alot of movement then if the floor it fixed to joists?

[doug boardley]

any chance of some scaled pictures kickkick, it's sounding dubious to say the least

[mikethetile]

you had me extremely worried there karl

to the point of ringing building control

you have no trusses in your chalet bungalow , which is a relief, you have what we call a cut roof

which basicly means cut and fitted in situ

the floor joists act as the lower tie and the ceiling joists over your head act as the collar or upper tie

so treat the floor as any suspended wooden floor

youve got very little deflection which is good , theres going to be some deflection on a suspended wood floor, but where does the sideways movement come in

if your floor joists have sideways movement you will need to lift the flooring and add noggins to take out the movement and relay the flooring

at the same time dump the chipboard floor and scew 18mm ply direct to your floor joists