Have used fast foot and but is expensive, and have heard of people using tyvek, is this a suitable replacement for fast foot, does it hold up to the concrete as well, and does it have the same effect as fast foot. basically is it usable instead of fast foot.
Thanks
N

It does the same thing plus Tyvek is much more readily available to me

I have used Tyvec as well as Fast Foot. Tyvec is much cheaper, more available (can pick it up in most hardware stores) and does the same thing.
Paul Stevens

Good idea, I will have to give it a try. I bet it saves a lot of time.

Saves a lot of money in concrete flowing out under the forms

so if you were doing an 8 or even 10 inch footins as I have to frequently do here, would you still use 2 x 4s and trust the tyvek to hold or 2x6s

yes, it will hold the concrete back on a 8 to 10 inch footing. I still prefer to use 2x8's when building footings that big but I do use the tyvec when I have a lot of steps involved, it is easier that cutting plywood to block in the sides, or when building on rock, Canadian shield, etc. it makes it lots quicker.
Paul Stevens

Does anyone do key-ways in your footings. If so how? I was thinking of putting a 2x4 on the underside of form spreaders.