expansion joint

[howard]

I'm starting a job on monday 36sm2 floor half the floor is concrete half is floorboards the problem i have is where they meet they dont run in a straight line some of the floorboards have been cut around a concrete block so there is no chance of putting an expansion joint there what can i do
cheers
Howard

[Turkish]

Hi Howard, i think you will have to have an expansion joint ptherwise trouble looms! You can buy pre made joints from Schluter i think that you can place and cut tiles up to. Hopefully someone with more experience will be along soon to either back me up or shoot me down in flames. Never had to do an expansion joint yet.

Turkish

[brian c]

hi howard,without seeing the job it sounds like you might need some ditra matting or some overboarding to do m8,you might however also need an expansion join aswell better safe than sorry m8.

[Dave]

Howard ...post a pic of the joint.....then we can decide which way to go.....you will need a movment joint but need to see what you are up against.......

[JEC-CTD]

A picture would be very helpful.

Its not just the expansion but also the differing stiffness in the two materials that you have to contend with.

[howard]

hi lads i dont have a picture the best way to describe it is the concrete has been laid like the letter F hope this makes sense

concrete this side of it F then floorboards this side

[howard]

any advice guys ?

[JEC-CTD]

I think Ditra matting would be good for this application but ask here technical@schluter.co.uk

[Dave]

If you have any movement between the timber and the concrete the an isolation membrane won't work......Ditra is designed to isolate lateral movement and not deflection. Howard i would try and straighten the joint up by cutting the timber side straight ( i.e removing the " F " from the floor) and infill with concrete.
Then put the movement joint where they meet and then use Ditra to isolate the stress between the floors , but still continue the joint through the substrate / Ditra and tiles........

good luck......

[JEC-CTD]

It would be good if you can do as Dave suggests but I suspect that replacing the timber section with concrete will not be easy if the timber section is a typical suspended floor. If it is suspended then how big is the gap underneath, overboarding may be one solution but as Dave said I believe it is the deflection that is your biggest problem.

Pictures really would help to give an informed opinion rather than us all guessing at the construction of the floor.

[howard]

already thought of that guys but the gap between the floorboards and under floor is about 2ft customer says just tile it what will be the consequences if i do i want to do this right despite what he says

[JEC-CTD]

Not easy that.

Peoples memories get short when they have aproblem with work you've done and they suddenly seem to forget that they said "just do it as cheaply as possible"

You want the work but you don't want a customer giving you a bad reputation, bad news travels faster than good.

Who is the customer, will they accept a disclaimer written into the price etc.

You could point them here I suppose.

[Dave]

If its that big a gap underneath ...then it is one of those jobs that's not to be done.......Don't take it on .......we are just clutching at straws here without seeing it.....

[JEC-CTD]

If the timber floor is very well supported then it may be OK for a while but I really would not trust it for long with a solid material like tile or stone.

I would be honest with them and say I'd only tile it if they accept in writing that you cannot be responsible for settlement or deflection between the two floor types.

If they say no then you have your answer.

Just my opinion.

[howard]

i have been honest with the guy hes a doctor bye the way he tells me he just doing his house up so he can sell it so as long as the tiles stay ok before he sells it i dont think hes arsed so should i take the same view as him even though i know its not right