which insulation in 30m stud wall??

Hi all.
I've just joined here & this is my 1st post, so just to say thankyou in advance to people who take the time to give me their replies.

Okay.
So I have been carrying out quite a lot of work to a property & the homeowner had decided to have the garage wall taken down & a new stud wall built further back to make the garage bigger & the kitchen/utility smaller.
The building inspector noticed it had been taken down so gave me specs of how he wanted new one built.
He wanted it constructed using 4x2 & boarded either side using fireline boards & 100mm kingspan or similar.
4x2 & fireline boards of course is fine, but the problem I'm having is getting hold of an fr 100mm insulation board.
Getting hold of 100mm celotex, kingspan etc isn't a problem but everywhere I ask (Travis perkins, B&Q, wickes, & all local builders merchants) say that they dont do a fire rated one.
I found a couple of other places that would get some for me but I had to order them by the pallet load & I only need a couple of boards.

So at last I'm getting to the point.
As its 100mm studs with 12.5mm fireline boards either side, I was wondering if anyone has done the same already & just used standard 100mm kingspan or celotex & if this is sufficient for 30m fire protection?
Or if I do it what is the likelihood of the building inspector telling me to take it out & use an fr board?

Thanks for taking the time to read this
Joe

 

There isn't a problem!.
If you put 'Fireline' board each side to 1/2 f.r., you could insulate it with anything suitable to meet Part L.
Come to think of it, I doubt you need 'Fireline' on the kitchen side - really only just on the garage side.

 

Hi Tony.

Thanks for taking the time to reply.
I have noticed from some posts that I have read that there are building inspectors on the forum who have replied to people so thought I might get a 2nd opinion from one, or another builder who has done the same just using standard 100mm kingspan or celotex.
inspector has said he wants it done with kingspan or celotex ect

I thought fire line just one side would cover it too but its been done the way I've been asked & boarding both sides with fireline (it makes no difference to me to be honest as its only the difference of a couple of quid)

I would have thought that standard celotex ect with fireline either side would be sufficient to give more than 30 min, but just didn't want the hastle of being told to remove the standard stuff.
However. the fact that no one stocks a fr board tells me that a standard board must be used by everyone else.

So in your opinion I assume that you agree that 12.mm fireline either side with standard 100mm celotex between is quite sufficient for 30min?

Regards
Joe

 

Just found this old thread that I had forgotten all about.
7 Years is a bit late for an update lol.
But yeah, in the end BC was happy that it had 100mm celotex & that it was fireline boards on "both" sides! A bit ott imo, but at the time speaking to other lads who did that area said he was a bit of a "Belts & Braces" type of bloke, & when it came to spotting anything "Extra" that a client had asked done once work had commenced. I found him a little awkward (Or more appropriately "Thorough") during the work, but actually a Great bloke to chat with once job was complete & he was happy everything had been done correctly.

 

Ah, but what would that constitute exactly? As best as I can recall, the White Book doesn't provide a spec for 30 minutes fireline (only soundbloc)