Questions of all Questions... deflection !

[terry the tiler]

was wondering at wot point of a quotation you would determine there was to much bounce in a floor ? i mean how do i no if i need to quote for taken up floors etc ? is a tiny bit bounce acceptable ? as the addy is flexi ?or is there something you can put down on a floor with slight bounce instead of ripping up floors etc ? the reason iam asking is that ive been to price up a lot of floor jobs , but starting to wonder about how much bounce (if any ) is acceptable ?

[mikethetile]

its difficult to explain, there is a bs standard on this but measuring deflection is difficult, I go to the middle of the floor and bounce on the balls of my feet if the if I can feel movement the floor has deflection, if I cant the floor has minimal deflection

the problem with tiling suspended wood floors is the joists are designed to deflect slightly to absorb shocks and noise and with a tiling system the floor needs to be rigid or cracks may appear across the floor, I have also seen the grout break up from the constant movement

its best to overboard anyway

[whitebeam]

I think the term Flexible adhesive and grout tend to give the wrong meaning to customers who have deflection on there floors.

Have seen a floor with bounce which was ditra'd and nicobond adhesive and grout was used, did'nt crack though

[doug boardley]

excellent question Terry, I feel that if it's a marginal point and the customer really doesn't want the floor ripping up, I can do it with S2 flexi adhesive due to it's enhanced flex properties. This, as a two part adhesive, is more expensive than a S1 type adhesive though. I must stress though, I do recommend replacing floors that have any deflection.

[Ajax123]

guess it depends what causes the deflection. Live Loading,\Dead Loading,\Soft body impact, hard body impact, creep etc etc.

Standard timber joists are designed I beleive to allow no more than L/300 where L is the length of the span and the result should be less than 12mm to meet NHBC standards. When we design timber floors to take Gyvlon Screeds in the soundbar system and other timber separating floors we allow for a design deflection of just 5mm. These are tiled regularly without any issues.

[doug boardley]

guess it depends what causes the deflection. Live Loading,\Dead Loading,\Soft body impact, hard body impact, creep etc etc.

Standard timber joists are designed I beleive to allow no more than L/300 where L is the length of the span and the result should be less than 12mm to meet NHBC standards. When we design timber floors to take Gyvlon Screeds in the soundbar system and other timber separating floors we allow for a design deflection of just 5mm. These are tiled regularly without any issues.

have we got an interpreter available please

[Ajax123]

have we got an interpreter available please

sorry doug.....

[mikethetile]

how do you measure if an existing floor has 5mm deflection

[Dave]

how do you measure if an existing floor has 5mm deflection

A string line diagonally from corner to corner and then measure with a tape when Nelly walks across it.

[doug boardley]

how do you measure if an existing floor has 5mm deflection

L divided by 300 Mike

[mikethetile]

A string line diagonally from corner to corner and then measure with a tape when Nelly walks across it.

[mikethetile]

L divided by 300 Mike

[doug boardley]

...... and then text Stephen Hawking to check

[Scott]

...... and then text Stephen Hawking to check

harsh Doug, he cant text back!