Will weeds cause cracking and deterioration? - Weeds between flagstones, cracking

[lomographic]

I have some flagstone paving laid directly onto a foundation- what kind of foundation I don't know- without cement and some cement dust between the flagstones to keep out weeds. Someone told me that the weeds that are growing there have caused cracking (that I thought had always been there) and will cause a lot more cracking and deterioration if I don't get rid of them soon.
Have you heard if weeds between loose-laid flagstones cause any cracking? And if so what do I do to take care of it, because getting in those cracks is hard? Do I have to get out the roots from under the flagstones?

[lutonlagerlout]

ideally yes
but you can always use a weedkiller first
I dont really understand this concept of loose laid flags
we have people in britain that lay flags like this,we call them cowboys :;):
cheers LLL

[Tony McC]

Weeds can only crack stone that is already weakened, and generally speaking, we don't use weak stone for paving (Fossil Fissile Mint excepted), so I can't understand how someone can suggest weeds will be the cause of amy cracking.

Do as LLL says: treat with a weedkiller and then look to get the flags professionally laid on a proper bed and with a good jointing medium.

[ringi]

I dont really understand this concept of loose laid flags
we have people in britain that lay flags like this,we call them cowboys :;):

Given that for many years all pavements were laid that way with the flags just on sand and no jointing, are you saying all pavements in my childhood were laid by cowboys?

[lutonlagerlout]

PCC slabs AKA council greys weigh between between 45 and 65 kg each,and are laid with edge restraints
so basically there is no where for them to go

the shed biscuits weigh around 5-10kg each and when laid on sand on grass or mud with no edge restraints are a sure fire fail

LLL