HELP! Firestops around openings in timber frame

I've a problem. Currently building a timber frame and the block work is half done. I intend to put in the windows afterwards.

Problem is that no fire stops have been put in around the openings, so far. Is there a product out there that will fit into the cavity that can be easily tacked to the frame? Or am I completely screwed.
Engineer is on holidays but he still never mentioned anything to me about this before he went!!

Help.

Firestops ???

cavity barriers are required around opes, and should come as part of the timber frame system. have you contated them??

fire stops are required at party walls or junctions with roof etc.

The timber frame co generally supply several lengths of 40 x 50 treated timbers for cutting and fixing around the window ope. These are set "flush" with the timber frame opes top and two sides. You should then staple a dpc to them. The tricky bit is cutting the two side pieces so they exactly finish flush with the top of the precast concrete cill.

If the block is finished on some window opes already, you can retro-fit the red fire stop bagging into the cavity.

A warning though.. if the block layers are slapping up the block without firestops in place, the chances are that they have omitted the stainless steel wall ties required each course right up each side of the ope...

Thanks for the replies.
I've paused the block layers so I can fit the battens around the opes this weekend. The guy from the timber frame was out today and explained all. The block layers have actually used more than the recommended number of wall ties - which is great.
I'm going to rent a gas nail guun this weekend and do the opes that have been blocked.

Just so I'm 100% - there is no need for a batten under the ope???

Thanks again..... heart rate back to normal.

there is no need for a batton under the ope as the cill will need to go under the window

therer is also a fireproof padding you can use around the opes.
this is available from nearly all good builders providers

regards