Hi i have been asked to detail the junction of a compartment wall with a roof in a residential care home. The compartment wall will be constructed of 215mm solid block work and the roof structure will be concrete tiles supported on timber battens and timber roof trusses.

I have been looking at approved document B diagram 30 (a),  but i am a little confused by their mention of "deck of material of limited combustibility". I would have assumed by the deck they were referring to a flat roof membrane supported on a deck of limited combustibility, typical slate or tile roof coverings do not have an underlying deck.

If the gap between the underside of my tiles and the top of my wall is filled with a resilient fire stopping material (rockwool) and my tiling battens are cut over the centre of my compartment wall do i need to protect my trusses for 1.5 meters either side of the compartment wall.

your thoughts and advice are much apprenticed

regards,

Stephen. 

  

I would agree with you "deck of material of limited combustibility" would be the flat roof membrane supported on horizontal joists and would not apply and statement 4 is more applicable to to your situation.

The roof trusses do not pass through the wall so I would think statement 3 does not apply.

Tom.

thanks for your reply

 

Regards,

Stephen.